What Is a Smart City?

Smart cities use innovative technologies to improve operations, expand access to goods and services, and get things done more efficiently. At the center of it all, transportation data is changing how cities make decisions that impact how people move.

smart city aerial view - NYC lights at night

Today, nearly everything has become “smart,” from phones to fridges, doorbells, and cars. And cities are no exception. Across the globe, cities large and small are adopting new technologies to improve quality of life, automate essential services, and integrate with the digital world.

So how exactly are “smart city” technologies changing how we live? And what role does transportation data play in making our cities “smarter”?

In this article, we’ll discuss:

What is a smart city?
Smart city technologies in use today
How smart cities use transportation data
Real-world examples of smart city transportation projects

What Is a Smart City?

A smart city is a city that uses data to optimize operations, planning, and governance. Data collected from residents and visitors, electronic devices and systems, and the broader Internet of Things is analyzed to understand patterns, monitor how things are going, communicate with constituents, and more.

If this all sounds incredibly broad, it is. Most cities today are smart cities, because data collection and analysis have become ingrained in just about everything we do.

Still, the extent and sophistication of data usage varies greatly from city to city. Below, we’ll explore some of the common ways smart cities are using this data.

*Ride hailing apps for taxis, microtransit, and rideshare services are common in today’s smart cities.*

Smart City Technologies

There are many types of smart cities technologies in use today. Some common examples include:

Real-Time Transit Tracking – GPS data from buses, subway cars, etc. are used to calculate wait times for public transit, communicated via mobile apps or station signage.
Energy & Utilities Optimization – usage data for electric grids, water, and more can be monitored and in some cases automatically adjusted to prevent service disruptions, detect leaks, anticipate the need for infrastructure improvements, or aid conservation efforts.
Smart Lighting – light detection technology can be used to automatically turn on overhead lights for roadways, parking lots, and more during poor lighting conditions (not just at nighttime).
Smart Traffic Signals – smart traffic lights use real-time data on the volume and speeds of vehicles approaching an intersection to automatically adjust the timing of signals to reduce idling time, improve traffic flow, or prevent unsafe conditions.
Air Quality Monitoring – sensors may be deployed throughout the city to monitor air quality, detect potential sources of pollution, communicate current conditions with the public, and inform air quality improvement efforts.

These and other technologies are becoming more and more common in cities across the globe. But one of the most frequently used forms of smart city technology is transportation intelligence. Below, we’ll discuss some of the key ways smart cities are using transportation data to improve mobility, air quality, climate impact, and more.

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How Smart Cities Use Transportation Data

Data on how people and vehicles move can help cities plan roadway infrastructure improvements, make land-use decisions, plan for special events, reduce traffic fatalities, monitor public health, boost economic activity, reduce commute times, mitigate greenhouse gas emissions, and so much more.

In many cases, cities will install physical sensors on the road that capture data on vehicle volumes, speeds, turning movements, and more. But these sensors are too expensive to install on every roadway, and they may not capture non-vehicle traffic such as bikes and pedestrians.

To get more comprehensive and cost-effective insights on how people move, cities often supplement physical roadway sensors with big data analytics. Big data platforms like StreetLight collect, process, anonymize, and validate massive numbers of datapoints from connected devices and the Internet of Things to make precise inferences about how people move.

Data privacy assurances are crucial when collecting big data on mobility. That’s why StreetLight’s Route Science® algorithm anonymizes and aggregates all datapoints, to ensure individuals can never be identified or tracked.

smart city traffic light above a snowy intersection — *Sensors connected to traffic lights help smart cities automatically synchronize smart traffic signals.*

In addition to smart traffic signals (mentioned above), which typically use data on vehicle volumes and speeds, there are many other ways cities are using transportation data. Common examples include:

Vehicle volumes to fix traffic jams, ensure smooth traffic flow during special events, and prioritize infrastructure investments
Speed data to understand where congestion or unsafe speeds are impacting mobility for residents and visitors
Turning movement counts to help time traffic signals
Origin-Destination and Routing patterns to measure tourism and plan detours, bus routes, or new EV charger locations
Annual Average Daily Traffic (AADT) counts to anticipate the need for repairs and inform safety planning
Bike and pedestrian activity to figure out where to install bike lanes, implement traffic calming measures, or add crosswalks
Truck activity and routing data to move goods efficiently, highlight emissions hotspots, or reduce dangerous cut-through traffic in residential areas

Real-World Examples of Smart City Transportation Projects

Cities across the globe are using transportation data to make smarter decisions. Here are just a few examples of smart city transportation projects in the U.S. and Canada.

Temecula Retimes Traffic Signals

After securing safety funds for new smart signals, Temecula, California needed intersection data to understand which signals were most in need of synchronization.

They used StreetLight’s turning movement counts to diagnose congestion across 40 intersections within a few hours, saving at least three months on data collection and analysis, and deploying funds effectively to optimize signal timing.

Vancouver Makes the Case for Bus Infrastructure

Multimodal transportation options help reduce congestion, improve climate impact, and ensure equitable access to essential goods and services. But with many transit agencies facing exceptionally tight budgets, proving the value of bus infrastructure investments is crucial to getting improvements implemented.

In Vancouver, city analysts used big data to reveal that bus mode share was much higher than previously understood, helping them gain political buy-in for new bus lanes and rapid lines to provide commuters accessible alternatives to personal vehicle use.

Richmond Measures Equitable Access to Multimodal Transportation

Transportation equity is gaining more attention, with grant programs like Reconnecting Communities and Safe Streets and Roads for All incentivizing projects that expand equitable access. But getting reliable measurements of transportation access is often a barrier to diagnosing and addressing existing inequities impacting city residents, especially among communities of color, low-income households, and people with disabilities.

In the video below, Alex Bell of Renaissance Planning explains how data from StreetLight helped city planners for Richmond, Virginia develop measures of multimodal accessibility and understand who was most underserved by existing infrastructure. This analysis revealed where infrastructure investments were most critical to improve transportation equity throughout the city.

To learn more about how big data transportation analytics can make your city smarter, download our free eBook, Any Road, Any Mode: Your Guide to the Transportation Data Revolution.

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How Can a Road Diet Improve Safety for Everyone on the Road?

How Can a Road Diet Improve Safety for Everyone on the Road?

road diet blog header - new york street with center turn , bike lane, and parking

America’s roads just keep getting wider. According to a Washington Post report, over a third of U.S. states spent more than $19 billion on expanding existing highways and road infrastructure in 2019. [1]

It’s a common way to attempt to curb the traffic congestion plaguing U.S. cities, but many transportation buffs say it’s the wrong approach. In fact, America’s road safety troubles may be directly related to its bloated urban corridors. The data appears to indicate that, in many cases, our roads don’t need to be fed more pavement — they need a diet.

The Federal Highway Administration (FHWA) points out that undivided four-lane roads — so ubiquitous in American cities — play host to a wide range of dangerous collisions, from lane-changing side swipes to bike and pedestrian crashes. These crashes are directly related to the volume and speed of traffic, but they’re also tied to the width and layout of the road. And, while it may seem counterintuitive, the path to increased safety without worsening congestion often lies in reducing lanes, rather than adding them, through a method called road diets. [2]

In this article, we’ll explore how road diets work to increase safety not only for vehicles, but also for pedestrians and cyclists. We’ll tackle the following:

What is a road diet?
Key safety considerations
How effective is a road diet?
Considering the alternatives
Finding the best approach with big data

So, What Is a Road Diet?

A road diet, or lane reduction, is a type of traffic calming measure designed to reduce speed and traffic congestion on an existing undivided roadway. Instead of expanding the existing road width with additional lanes, planners reduce the number of standard traffic lanes to make room for other types of lanes or road features.

Road diets are most common on four-lane highways. Typically, planners exchange the existing four driving lanes for a center left-turn lane flanked by two standard driving lanes and bike or pedestrian lanes. Other road diet examples include replacing two lanes with a tree-lined median or adding parking on the sides and narrowing existing lanes.

VDOT road diet example — *Photo source: Virginia DOT, reprinted in the U.S. DOT’s Road Diet Informational Guide*

Whatever the specific approach, the overarching goal of a road diet is simple: to lower traffic speed and thus reduce the number and severity of crashes. In the process, this measure can also enhance the overall quality of life and appeal of an urban area by making more room for cyclists and pedestrians, expanding common areas, and even adding more green space to popular thoroughfares.

Key Safety Considerations

Understanding the value of road diets first requires an appreciation of just how threatening many of our busy four-lane, undivided roadways are. These popular road layouts are riddled with safety concerns for drivers, passengers, pedestrians, and cyclists alike. Before making any change to an established roadway, it’s essential to understand the dangers of the existing layout.

For Vehicles

In urban and suburban areas, four-lane, undivided highways are hot zones for vehicle-to-vehicle crashes. There are simply too many potential collision points for drivers to track. Such corridors are commonly home to all sorts of collisions:

Rear-end collisions from sudden stops or vehicles waiting to turn
Sideswipe crashes during lane changes
T-bone or angle collisions from cars turning left across oncoming traffic
Multi-car crashes at intersections

These collisions occur due to a range of factors, many of which can be addressed through road diets. High speed differential between lanes or intersecting streets can lead to sudden stops or miscalculations that result in collisions. Left turns across multiple lanes are also inherently dangerous. [2]

The specific traffic patterns and risks vary by location. When assessing the potential benefits of lane reductions, planners need data that allows them to analyze metrics like average speed, speed differentials, average traffic volumes, and typical turn counts at intersections.

For Pedestrians

As problematic as four-lane roads are for vehicle-to-vehicle crashes, they’re even more hazardous for pedestrians. Drivers hit and killed more pedestrians in 2022 than in any year since 1981, and these types of roads are at the center of many such collisions. [3] As one recent study revealed, 97% of the hot spots for pedestrian deaths in the U.S. are multi-lane roads. [4]

pedestrians crossing multilane highway — *Pedestrians cross a multilane roadway.*

Crashes on such roads occur for many reasons, from a lack of sidewalks to pedestrians misjudging oncoming vehicles when crossing multiple lanes. However, the central problem on wide urban streets is vehicle speed. Studies show that pedestrians are five times more likely to die from crashes when cars are traveling at 40 miles an hour than at 20 miles an hour.

Here again, data is crucial for determining the right solution. Understanding vehicle speeds, the volume of pedestrian traffic, and the frequency of pedestrian collisions can help planners assess whether a road diet — and which type — would provide an effective solution.

For Cyclists

According to the National Safety Council, more than 850 cyclists died in collisions with vehicles in 2021. [5] Many of these incidents were linked to unsafe road conditions. [6] The FHWA reports that the simple addition of a bike lane could reduce bike crashes by 49% on four-lane roads. [7]

Beyond being an argument for bike lane additions, this is a strong point in favor of considering road diets on cyclist-heavy city roadways. Road diets are designed to reduce traffic speed, and they can make room for more extensive road modifications such as protected bike lanes, which are physically separated from vehicle traffic.

See how dangerous traffic speeds impact walking and biking in your region

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How Effective Is a Road Diet?

Overall, the data shows that road diets are often highly effective at increasing safety. Based on broad studies, the FHWA states that road diets can reduce crashes by between 19% and 47%. [2] In Seattle, a 2008 road diet reduced pedestrian collisions by 80%. The same project saw a 35% increase in cyclist traffic without any increase in bicycle-involved crashes.

To project the impact in a specific area, planners must account for various factors, particularly existing traffic volume. Lane reductions tend to be most effective on roads with between 8,000 and 20,000 average daily vehicles. [8]

Despite these benefits, many people are skeptical of road diets. In Los Angeles, the firefighters union recently launched a campaign against proposed road diets, claiming they would hinder emergency vehicles by increasing congestion. [9] Others argue they would slow down public transportation or simply divert heavy traffic elsewhere. [8]

Broadly speaking, the evidence to support these claims is slim. Although lane-reduction projects occasionally get pulled back, research shows that these road diet failures often occur due to a disconnection between public perception and reality. In other words — the project accomplishes its goal, even if the public thinks it’s not working.

That’s not to say these tactics are the right solution for every safety or traffic congestion problem. However, the evidence does indicate that when planners closely evaluate the many variables of a situation and decide to implement a road diet, the resulting safety enhancements are usually significant. [10]

Finding the Best Approach With Big Data

As noted, road diet success is much more likely with a deep analysis of traffic patterns. Understanding metrics like turning movement counts, average daily traffic volume and speed, speed differentials, and stopping frequency is essential for an accurate assessment of any potential project.

Big data platforms like StreetLight InSight® can expedite data collection when evaluating a potential road diet, providing detailed visualizations of traffic patterns and trends to help planners conduct a thorough road safety audit before making any decisions. This approach also makes the data collection itself safer because agency staff need not put themselves at risk to take manual counts along dangerous roadways. Furthermore, big data can provide a more complete view of roadway conditions than manual counts, which are usually limited to a small snapshot of traffic during peak driving hours on a particular day or a few days.

Many agencies are already using big data to evaluate potential road diets, as well as the success of past road diets. As the video below explains, Maine’s Department of Transportation used Streetlight tools to conduct a detailed analysis of its Bangor Street road diet proposal, filling in critical data gaps to understand turning movement counts, side-road traffic, and complex roundabout traffic flows.

Similarly, a StreetLight analysis of roadway capacity, vehicle speeds, routing patterns, and pedestrian activity suggested that a road diet on Oakland’s Grand Avenue could help address safety concerns without causing major congestion.

potential road diet locaiton on Grand Avenue in Oakland — *Grand Avenue, part of Oakland’s High Injury Network, could be a good candidate for a road diet treatment.*

After implementing a road diet, big data transportation analytics also allow planners to easily measure any changes in traffic volumes, routing, safety, and critical metrics like Vehicle Hours of Delay (VHD). These insights simplify the process of assessing project potential and outcomes so planners can do their work more effectively.

For more information on how big data can help you find the best safety solutions for your streets, check out our Safety Data Handbook.

The Washington Post. “Infrastructure plan calls for fixing the nation’s existing roads. Some states are still focused on expansion.” https://www.washingtonpost.com/transportation/2021/05/23/highway-funding-infrastructure/
U.S. Federal Highway Administration. “Road Diet Informational Guide.” https://safety.fhwa.dot.gov/road_diets/guidance/info_guide/ch1.cfm
Governors Highway Safety Administration. “Pedestrian Traffic Fatalities by State: 2022 Preliminary Data.” https://www.ghsa.org/resources/Pedestrians23
Journal of Transport and Land Use. “United States fatal pedestrian crash hot spot locations and characteristics.” https://jtlu.org/index.php/jtlu/article/view/1825
National Safety Council. “Bicycle Deaths.” https://injuryfacts.nsc.org/home-and-community/safety-topics/bicycle-deaths/#:~:text=In%202021%2C%20most%20deaths%20occurred,for%20Health%20Statistics%20mortality%20data
NPR. “More cyclists are being killed by cars. Advocates say U.S. streets are the problem.” https://www.npr.org/2022/05/25/1099566472/more-cyclists-are-being-killed-by-cars-advocates-say-u-s-streets-are-the-problem
U.S. Federal Highway Administration. “Bicycle Lanes.” https://highways.dot.gov/safety/proven-safety-countermeasures/bicycle-lanes
AARP. “Road Diets: A Livability Fact Sheet.” https://www.aarp.org/content/dam/aarp/livable-communities/livable-documents/documents-2014/Livability%20Fact%20Sheets/Road-Diets-Fact-Sheet.pdf
Los Angeles Times. “Firefighters launch campaign against Measure HLA, saying ‘road diets’ threaten safety.” https://www.latimes.com/california/story/2024-02-14/firefighters-launch-campaign-against-measure-hla
Scientific Research. “A Comprehensive Study of a Road Diet Implementation in the US and Abroad.” https://www.scirp.org/journal/paperinformation?paperid=127799#:~:text=The%20road%20diets%20were%20implemented,were%20implemented%20across%2066%20projects

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Better Budget Planning with Big Data: 4 Ways Transportation Agencies Use Data to Build Budgets, Secure Funds, and Save Money

blue background with U.S. dollars, credit card, and hand holding stopwatch

With transportation agencies across the U.S. facing a dreaded “fiscal cliff,” budget challenges are top of mind for many StreetLight users. Thoughout the year, but especially as fall approaches, transportation professionals are under pressure to make next year’s budget as efficient as possible, and find last-minute ways to use remaining funds effectively before they’re lost in the budget rollover.

Recent years have introduced added complexity to the budgeting process. While the Bipartisan Infrastructure Law (BIL) passed in November 2021 offered billions in new funding opportunities, the traffic disruptions of the pandemic also introduced added difficulty in anticipating travel demand, planning projects, and following through on existing plans.

But budget concerns didn’t end in 2021. Agencies of all sizes are facing limited funds while working to address a pedestrian safety crisis, returning traffic congestion, urgent emissions reduction efforts, a growing EV revolution, and lots more.

Amid these challenges, big data–powered traffic analytics are helping agencies with a few key budgeting needs:

Planning and prioritizing next year’s projects to build effective, justifiable budgets
Save money over traditional data collection methods with validated, on-demand data
Secure additional funding with data-supported grant applications
Use leftover funds quickly and effectively, before they are lost in the fiscal year turnover

Below, we’ll explore specific examples collected from panels and discussions that illustrate how shrewd practitioners are using Big Data analytics to meet these budgeting challenges.

1. Prioritizing Projects for Next Year’s Budget

At our 2020 StreetLight Summit, when many projects were in limbo, transportation professionals told us they were ramping up on planning. That way, when budgets were settled and projects could begin again, planners would be confident they’d analyzed and prioritized the most important work.

Although this was top-of-mind during the disruptions of the early COVID pandemic, this insight is evergreen. When agencies have the data to effectively prioritize next year’s projects, that data can also be used as evidence to justify next year’s budget and support its approval.

At the 2020 StreetLight Summit, planners shared examples of running multiple analyses for each project, and studying before-and-after results to measure impact of existing projects.

For example, FDOT needed to decide where to install 11 continuous bike and pedestrian counters along thousands of miles of bike trails and lanes in Florida. Planners instinctively felt that the University of Florida in Gainesville would be a prime location, and took the time to verify that instinct.

“If we are going to invest in putting up count stations that cannot be moved, we need to be confident there will actually be activity at that count station,” explained Eric Katz at FDOT.

Figure 1: A Zone Activity analysis marking potential location for a continuous bike counter on University Avenue in Gainesville, Florida.

Katz confirmed a steady stream of bike/ped travel in the area, plus trip duration and trip speed, by running a StreetLight Zone Activity analysis. The study pinpointed additional Florida locations for short-term counters, including a popular bike trail in the Panhandle.

2. Save Money Over Traditional Collection Methods

To operate effectively, agencies rely on data-informed project planning. But answering key questions about existing mobility conditions can often strain budgets.

Access to on-demand traffic data is often far more cost effective than sensors or surveys, allowing agencies to operate with a more comprehensive understanding of mobility in their communities.

For example, understanding routing — where trips start and end, and the path they take along the way — often requires costly surveys that may also face sampling limitations.

But big data can provide O-D analytics at larger sample sizes without the delay or cost of surveys.

At the 2020 StreetLight Summit, Lucile Kellis of Steer shared an origin-destination analysis designed to help a transit client size unmet travel demand. First, Steer used StreetLight to identify where transit users were ultimately going to and coming from, to highlight strategic travel corridors.

Then they went further by gleaning additional insights about the travelers themselves. But rather than incur what would be an additional survey expense, Steer leveraged the StreetLight InSight platform.

“Typically our clients have a good understanding of who their customers are, but not the people who they want to attract,” Kellis explained. “Surveys are a good tool to collect that information, but we all know that good surveys are expensive and they return results with low sample size and biases. StreetLight helps us solve these issues at a much cheaper cost.”

Figure 2: Using demographic information from StreetLight InSight Steer’s analysts built a dashboard capturing transit persona data.

Similarly, when MnDOT wanted to understand sources of traffic on Dodd Road, on-demand traffic analytics helped them avoid prohibitive survey costs.

Figure 3: MnDOT’s analysis confirmed that Dodd Road’s traffic was primarily made up of local trips, not cut-through traffic.

“We normally wouldn’t answer this community question because the survey spend wouldn’t be cost effective,” says Michael Corbett at MnDOT. Corbett’s team was receiving complaints about cut-through traffic in a particular neighborhood. But with unlimited analyses via the agency’s StreetLight InSight subscription, MnDOT was able to identify the source of neighborhood traffic, and share results with constituents.

Budget limitations often demand that some concerns remain unaddressed, even for well-funded state DOTs and large MPOs. Meanwhile, small to medium-sized cities may have an even tougher time addressing resident reports of cut-through traffic, congestion and delays, or unsafe vehicle speeds.

Access to big data can allow these cities to investigate and validate resident complaints more affordably, shifting funds that would have been spent on data collection to actually implementing solutions. Plus, with information on the entire transportation network, and the ability to evaluate the impact of past projects with before-and-after analyses, cities can more confidently choose the most effective solutions and ensure funds are not wasted.

Other traditional data collection methods — such as automatic traffic counters or manual field observation — can also drive up costs. In 2019, one DOT ran a cost-benefit analysis to compare StreetLight’s platform to traditional methods and found a 50:1 benefit-cost ratio (click here to learn more about cost-benefit analyses).

3. Secure Grant Funding

Data-supported grant applications help agencies stretch their budgets and fund projects that might otherwise end up on the chopping block or face considerable delays.

To tell a story grant administrators want to hear, agencies need evidence that their proposed project will significantly benefit their community. But as we’ve explored above, traditional data collection can be costly and time-consuming, leaving agencies with a catch 22.

Big data can help build a compelling grant application with clear visualizations and benefit-cost analyses using recent, validated data on existing conditions.

For example, when ODOT sought funding for Phase 4 of a multi-year, $1.3 billion highway restructuring project, they used StreetLight metrics and visualizations to secure a $25 million Infrastructure for Rebuilding America (INFRA) grant.

Big data has also been pivotal in securing funds for safety projects. Agencies that have leveraged StreetLight for Safe Streets and Roads for All (SS4A) applications have won ~$8 Million in SS4A grant funding.

4. Use Funds Effectively Before It’s Too Late

Because many agencies have use-it-or-lose-it funds, the end of the fiscal year often adds urgency to fund implementation. How can agencies use leftover funding effectively for their communities, with limited time left in the year?

Because big data analytics don’t face the same delays that traditional data collection methods do, they can allow agencies to quickly identify optimizations on existing roadways and allocate funds for quick fixes like signal retiming or optimizing bus schedules.

Big data can also help agencies funnel these leftover funds into planning for next year.

For example, when planners in the Shreveport, Louisiana area had concerns about traffic congestion and safety, they used StreetLight to get a comprehensive look at regional traffic, pinpoint congestion hotspots, and quickly build a data-supported mitigation plan.

This approach also relieves budget stress by allowing managers to use their staff resources more efficiently. Chris Petro, AICP, of the Northwest Louisiana Council of Governments (NLCOG) put it this way:

What Is a Stroad, and Why Is It Dangerous?

Part road, part street, the all-too-common stroad creates dangerous conditions, especially for non-motorists like pedestrians and cyclists. But what makes them so deadly, and how can data on traffic conditions help find and fix them?

In our increasingly suburbanized North American landscape, stroads are a cornerstone of the car-centric transportation paradigm. These bare-bones high-speed roadways are often devoid of any pedestrian- or bike-friendly infrastructure, subjecting drivers and non-motorists alike to dangerous conditions when commuting, shopping, or accessing essential services.

The drawbacks of the stroad stem from its hybrid nature: it attempts to connect people with key destinations (goods, services, city amenities) while also getting people from point A to B as quickly as possible. Far from being the best of both worlds, stroads often fail to accomplish either of these goals particularly well.

So what exactly is a stroad, and how can we make them less dangerous? In this article, we’ll discuss:

What is a stroad?
The problem(s) with stroads
How to fix stroads
Data to improve safety on stroads

What is a stroad?

The term “stroad” was first coined in 2011 by Charles Marohn to describe a roadway that combines elements of a street and a road.¹ So what is the difference between a street and a road?

Streets are destinations — they provide access to goods, services, and recreation. They are often found in dense urban cores, especially downtowns, where shops, restaurants, parks, salons, doctors’ offices, and more dot every corner. These kinds of roadways typically have fewer lanes, slower traffic, and signalized crosswalks to accommodate plenty of foot traffic.

*Streets typically have low speed limits, a low number of narrow lanes, ample sidewalks, and provide access to businesses, housing, and recreation.*

Roads, by contrast, connect destinations to one another, prioritizing efficient traffic flow to get people from point A to point B. Consider a highway between cities, or between a downtown core and a suburb or exurb. These types of roadways typically have more lanes, higher-speed traffic, and limited to no access for non-motorists like walkers and bikers.

*Roads typically have a larger number of wider lanes, higher speed limits, and limited to no access to non-vehicle traffic. They act as efficient connectors between destinations.*

Stroads combine elements of both, acting as both destination and thoroughfare, which results in wide, high-speed roadways with sparse walking and biking infrastructure that are nevertheless crucial access points for goods, services, and recreation. These kinds of roadways are common around malls, strip malls, and other suburban hubs, but also frequently cut through urban cores — many downtown Main Streets are also stroads. Wherever they crop up, they usually feature speed limits between 20 and 50 miles per hour.²

When stroads manifest in the suburbs, it’s often because roads that were once used to connect suburban residents to the downtown core become attractive places for new shopping centers, restaurants, movie theaters, and more, boasting plenty of cheap space for sprawling supercenters and parking lots. Thus, roads that become host to these kinds of destinations are often doomed to morph into the dangerous stroad hybrid.

Stroads are also common in urban cores, especially where priority is placed on accommodating the high vehicle throughput that is common in these areas.

example of a stroad — Stroads typically provide access to business and recreational destinations while featuring multiple wide lanes, higher traffic speeds, and minimal infrastructure for non-motorists.

The problem(s) with stroads

In addition to being dangerous, stroads also have other negative impacts on public health and the local economy.

Why are stroads dangerous?

As mentioned above, stroads lack many of the necessary features that make streets safe for walking and biking, such as signalized crosswalks, protected bike lanes, slow vehicle speeds, and short crossing distances.

But it’s not just Vulnerable Road Users who experience dangerous conditions on stroads. These roadways are also difficult for drivers to safely navigate due to high-speed traffic across multiple lanes with many entry and exit points from driveways and parking lots providing access to roadside destinations.

Stroads often subject drivers to unprotected left turns to cross multiple lanes of high-speed traffic, or right turns where they could easily collide with cyclists and pedestrians traveling in the same direction across unmarked driveway crossings.

How do stroads impact emissions?

Stroads incentivize vehicle travel over lower emission forms of transportation like walking and biking. This, compounded by the fact that high-speed travel produces more emissions than slower driving, makes stroads emissions hotspots.

This not only contributes to climate-harming greenhouse gases, but also worsens air quality for those who live near these hybrid roadways.

Are stroads bad for the economy?

Although stroads connect consumers with shopping centers and other businesses, many are also unattractive and costly, compromising their ability to support the local economy.

Vast, undifferentiated expanses of asphalt and concrete are common to stroads, multi-lane roadways and parking lots dominate the landscape. Coupled with poor safety, this creates an uninviting environment, disincentivizing frequent trips and extended visits.

These factors also make stroads costly. While these high-volume, high-speed roadways must undergo expensive maintenance due to considerable wear and tear, they also often generate less economic activity and property tax revenue than true streets do.³

See how dangerous traffic speeds impact walking and biking in your region

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How to fix stroads

Fixing a stroad isn’t always simple, because they represent a confluence of competing land use and transportation goals: promote efficient vehicle travel while also facilitating economic opportunity and access to goods, services, and recreation.

A stroad usually evolves because land use practices have already allowed for business developments along an existing roadway, at which point it is too late to prevent the evolution of a stroad, but not too late to fix it.

Can stroads be prevented?

But it is possible to prevent the creation of a stroad in the first place through intentional land use practices. This would involve restricting new development along existing roads and allowing for more dense development along more people-friendly streets. Restricting the expansion of existing roadways (through lane widening or added lanes) can also help prevent street-to-stroad evolutions.

Similarly, reducing or eliminating parking minimums can allow for denser, less car-dependent hubs of development while also incentivizing non-vehicle modes of travel.

Preventing stroads could also involve converting roads into streets when new developments are proposed along existing roads. Below, we’ll explore some strategies for turning roads or stroads into streets.

Turning stroads into roads

Because stroads already have businesses, services, and/or city amenities in residence, fixing a stroad usually means turning it into a proper street. Turning a stroad into a road is not always possible, because it might require removing existing destinations and potentially relocating them elsewhere — a costly, unpopular, and time-consuming prospect for businesses and residents alike.

In cases where stroads are converted into roads, this means prioritizing vehicle throughput, minimizing entrance and exit points along the road (e.g. reducing the number of driveways leading to shopping centers and other roadside destinations) and eliminating pedestrian and bike access to the road (potentially creating separated bikeways and pedestrians paths).

Turning stroads into streets

To make stroads safer, more sustainable, and better for the economy, cities can explore redesigning roadways to implement more street-like elements.

One powerful tool for turning stroads into streets is the road diet. Road diets remove or repurpose existing lanes of traffic in order to create safer, lower speed corridors. While this tactic is sometimes controversial due to concerns that removing lanes will increase congestion, careful traffic analysis often reveals that road diets do not create significant delays in travel time, especially if they make roadways safer for non-vehicle modes of travel or reroute a portion of traffic to other high-capacity roads.

*A road diet may repurpose existing vehicle lanes to create space for buffered bike lanes (highlighted in green) or other multimodal infrastructure.*

Similarly, adding multimodal infrastructure, especially infrastructure focused on bike and pedestrian safety such as protected bike lanes, signalized crossings, and pedestrian islands can help eliminate the common dangers of stroads. A Complete Streets policy can establish helpful guidelines for turning stroads into streets that accommodate all road users.

In addition to road diets, other traffic calming tactics such as reducing speed limits, narrowing lanes, or adding street art and landscaping can protect vulnerable road users from one of the top factors contributing to high traffic fatality rates: dangerous vehicle speeds. While street art and landscaping have been shown to reduce average driving speeds, they also help beautify stroads, making them more inviting and better for business. Adding lighting and benches can also further these goals.

Reducing parking, especially in locations with vast parking lots such as shopping centers, also helps disincentivize vehicle use and encourage other modes of travel like public transit, walking, and biking. Furthermore, eliminating parking can also free up space for housing, parks, dining courts, or other developments that give people reasons to visit more frequently and for longer periods of time, boosting economic activity.

In any case, converting a stroad into a street often takes time and may involve multiple strategies, so cities should focus on incremental improvements.³

parking lot with hundreds of spots empty

Data to improve safety on stroads

To find and fix stroads effectively, analyzing current traffic conditions is crucial. The following metrics can help planners and engineers understand where stroads are putting people at risk and determine the best strategies to address them:

Vehicle speeds – to pinpoint which roadways may qualify as stroads and monitor risk for Vulnerable Road Users like pedestrians and cyclists
Biking and Walking activity – to understand where Vulnerable Road Users contend with dangerous conditions and where to prioritize infrastructure to improve their safety and connectivity
Vehicle volumes – to understand roadway capacity and help assess whether a stroad should be converted into a road or a street
Routing and Origin-Destination patterns – to evaluate the potential for stroad-to-street conversions and where traffic could be rerouted or shifted to other modes like public transport
Turning Movement Counts – to determine where traffic lights, signalized crosswalks, or signal retiming can keep traffic flowing while improving safety

For a comprehensive guide to transportation safety analytics, download our Practitioner’s Guide to Transportation Safety.

Ben Abramson. Strong Towns. “5 Telltale Signs You’re on the Stroad From Hell.” January 19, 2023. https://www.strongtowns.org/journal/2023/1/19/5-telltale-signs-youre-on-the-stroad-from-hell
Strong Towns. “What’s a STROAD and Why Does It Matter?” March 2, 2018. https://www.strongtowns.org/journal/2018/3/1/whats-a-stroad-and-why-does-it-matter
Reliance Foundry. “Bad Urban Design: How do you fix a stroad?” https://www.reliance-foundry.com/blog/how-to-fix-a-stroad

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What Is Congestion Pricing, and Is It Always the Right Choice?

congestion pricing scenario in Manhattan, NYC

In the nation’s busiest urban areas, transportation planners are faced with the urgent task of finding the best way to solve traffic congestion. According to data from Texas A&M, commuters in America’s largest cities lose 84 hours per year, on average, to congestion. In sprawling cities like Los Angeles and Washington, D.C., the problem is particularly egregious, with drivers losing more than two hours per day to slow-moving traffic. [1]

In the past, planners would have turned to the obvious but unreliable solution of expanding highways and adding lanes to address this problem. However, as that approach has often been shown to make congestion worse, planners are now expanding their array of potential solutions. Chief among them, in many cases, is congestion pricing.

This method of addressing traffic congestion pushes more of the cost of maintaining the busiest roadways onto those who use them. Ultimately, it aims to reduce traffic and speed up the commute for those who lack other options. Congestion charges can be an effective way to reduce congestion and support other transportation and public health goals, but it’s worth analyzing other solutions to determine the best route for your city and to make sure you can make a compelling case for any pricing strategy.

In this article, we’ll explore the following:

The critical issue of traffic congestion
What is congestion pricing?
Perks and drawbacks of a price-based approach
Other options to consider
How to know if congestion pricing is right for your city

The Critical Issue of Traffic Congestion

For many U.S. drivers, unmitigated traffic congestion may just seem like an irritating fact of life. However, its economic implications are far more serious, and its environmental consequences much more dire than a mere daily nuisance.

In cities with some of the worst congestion, the daily lurch of traffic amounts to billions of dollars in annual losses. From the expense of wasted fuel to the cost of increased accidents, congestion takes a severe economic toll. In high-traffic cities like Chicago, Los Angeles, and New York, these costs range from $7.6 billion to $11 billion every year. [2]

The price may be even greater when it comes to pollution and its adverse health effects. For instance, research has shown a direct correlation between traffic volume and the concentration of nitrogen oxides and other pollutants. Regular exposure to these high concentrations during daily rush hour traffic has been associated with increased risks of health problems and even death. [3]

The rise in pollution in conjunction with congestion isn’t merely a function of a higher number of cars. Studies have shown that slower-moving, stop-and-go vehicles produce higher levels of pollutants, exacerbating poor air quality for those who sit in traffic every day or who live and work near congested highways — people who are often members of already disadvantaged communities. [4]

Such immediate costs and public health concerns make traffic congestion a top concern for transport planners in America’s most populated areas.

What Is Congestion Pricing?

Congestion pricing is an increasingly popular way to address traffic problems in busy areas. This approach can take various forms, but they all work in basically the same way — they charge drivers to use busy roadways. This is designed to encourage drivers to carpool or consider alternate routes or methods of transportation.

These tollways may operate at all times or only during certain high-traffic periods. They may apply to all drivers on a specific route or, for instance, only to those using high-occupancy vehicle (HOV) lanes without meeting the occupancy requirements. Others may apply road pricing to those who use express lanes to bypass busy corridors. Whatever the specifics, the idea is to apply a “congestion tax” to those who contribute to the clogging, rather than levying a road or fuel tax against all drivers in a given region. [5]

Perks and Drawbacks of a Price-Based Approach

Are congestion fees the best way to address the problem? That depends on several factors, which we’ll detail below.

Proven Benefits

In the right context, congestion charges bring several important benefits, from reducing traffic to supporting broader transportation initiatives.

Congestion Fees Are Effective at Reducing Traffic

In many cities that have implemented congestion pricing, the effect on traffic volume has been dramatic. In Orange County, California, the tactic doubled vehicle throughput while increasing speed in free lanes three- to fourfold. [5] When London instituted road pricing two decades ago, it reduced congestion by 30%. [6] Stockholm, which introduced its congestion tax a few years after London, saw a net drop in traffic of 20%. [7]

But achieving these outcomes requires a detailed analysis to ensure it will be implemented effectively.

Road Pricing Has Health Benefits

As expected, these drops in traffic are accompanied by reductions in pollution. During the first year of London’s congestion pricing program, the city saw nitrogen oxide emissions drop by 13.5% and particulate matter in the air diminish by 15.5%. Research estimates this has added nearly 1,900 years to the lives of London residents over the course of the program. In Stockholm, meanwhile, hospital visits for childhood asthma have dropped by nearly 50%. [8]

It Supports Other Transportation Goals

Congestion pricing can also be introduced in conjunction with other forms of traffic engineering to support a comprehensive strategy for reducing traffic in overloaded areas. London’s system shifted 10% of commuters toward walking, cycling, or relying on public transportation. In the city center, bus travel increased by a third. [6]

Cities can use the revenue generated by congestion fees to directly support other transportation initiatives, whether that involves renovating bus stops, adding bike lanes, or supporting forms of micromobility. While congestion pricing programs do bring their own expenses, even a small boost in revenue from these programs can be beneficial for cash-strapped planning departments. Again, it’s essential to delve into traffic data and project the impact of any changes before implementing any specific program.

Criticisms and Limitations

Despite these benefits, congestion pricing garners its fair share of criticism, most of which falls into one of three categories.

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The Model Is Unfair

Many critics have raised legitimate concerns over where congestion pricing can be implemented equitably. After all, drivers with lower incomes will find the tolls more difficult to manage than those with more resources.

However, it’s important to note that many models are structured to address these potential inequities. San Francisco’s proposed pricing model, for example, would offer a sliding scale for congestion charges based on income level or disabilities. Likewise, the proposal offers to put some of the revenue from fees toward boosting transit service to underserved locations and even offering free transit to low-income riders. [9]

Congestion Pricing Is Unconstitutional

In some cases, opponents of this type of traffic engineering have gone so far as to question its legality. New York City’s Metropolitan Transportation Authority is now facing a lawsuit from New Jersey claiming that its current plan for congestion pricing violates the U.S. Constitution, which doesn’t allow states to enact laws that may place undue burdens on interstate commerce. [10] It’s not clear whether the suit will stand up in court, but it’s safe to say there is precedent for states enacting tollways, even where it affects out-of-state residents.

Other Options to Consider

Where there are significant barriers to successful implementation, it’s worth exploring alternatives that can be deployed in conjunction with (or as an alternative to) congestion pricing.

Road Diets

Road diets take a counterintuitive approach to solving congestion issues, but they can be quite effective. Instead of adding lanes, this method seeks to remove or repurpose existing lanes to slow down traffic, reduce demand, and increase safety.

For instance, Santa Monica, California, was able to reduce crashes by 65% in one corridor simply by converting a four-lane road into three lanes with a shared left-turn lane and outer bike lanes. [11]

Adjusting Traffic Flow

Planners can also look for ways to modify the existing flow of traffic in busy corridors. For instance, this might involve rerouting trucks to free up space or making more proactive plans for when and where roadwork is done. Signal timing adjustments can be particularly helpful in this regard.

However, as city planners found in Temecula, California, this often requires extensive data on turning movement counts (TMC) for various intersections. Fortunately, that’s no problem with the right tools on hand.

Multimodal Transportation

Finally, planners should also consider how they can facilitate more diverse forms of transportation. This is especially necessary if they implement congestion pricing, as it’s critical to have alternative modes of transport for people to choose if the tolls are cost prohibitive.

A multimodal transportation approach expands these options by adding more public transit, bike lanes, pedestrian routes, micromobility, and more. In the same vein, Complete Streets policies can help ensure accessibility for non-motorists, and counteract the equity concerns that are often raised by congestion pricing.

How to Know if Congestion Pricing Is Right for Your City

As with any approach to solving congestion problems in your city or region, there is no definitive solution. Before implementing congestion pricing, it’s essential to conduct a deep analysis of traffic data in congested areas so you can project how any proposed adjustments might affect the flow of traffic.

StreetLight InSight® makes such a deep analysis possible by providing traffic data from virtually every angle. In Napa Valley, data on commute origins helped planners realize that focusing on public transportation could significantly reduce congestion. In Temecula, TMC metrics facilitated a revamp of signal timing. In Atlanta, data on driver demographics and rush hour volume is shedding light on whether congestion fees will improve traffic flow.

To learn how you can use data to determine the right congestion solutions for your city, download Everything But Highway Expansion: Better Data for Faster Congestion Mitigation.

Or, watch how quickly you can analyze local congestion with StreetLight’s Congestion Management solutions in the 3-minute demo below.

Texas A&M Transportation Institute. “2021 Urban Mobility Report.” https://static.tti.tamu.edu/tti.tamu.edu/documents/mobility-report-2021.pdf
Forbes. “Traffic Congestion Costs U.S. Cities Billions Of Dollars Every Year [Infographic].” https://www.forbes.com/sites/niallmccarthy/2020/03/10/traffic-congestion-costs-us-cities-billions-of-dollars-every-year-infographic/?sh=3af966ea4ff8
National Library of Medicine. “Air pollution and health risks due to vehicle traffic.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4243514/
Research Journal of Chemistry and Environment. “Urban traffic congestion: its causes-consequences-mitigation.” https://www.researchgate.net/publication/367208770_Urban_traffic_congestion_its_causes-consequences-mitigation
U.S. Federal Highway Administration. “What Is Congestion Pricing?” https://ops.fhwa.dot.gov/congestionpricing/cp_what_is.htm
Transport for London. “Congestion Charge marks 20 years of keeping London moving sustainably.” https://tfl.gov.uk/info-for/media/press-releases/2023/february/congestion-charge-marks-20-years-of-keeping-london-moving-sustainably
University of Illinois at Urbana-Champaign. “Downtown congestion pricing in practice.” https://www.researchgate.net/publication/331152719_Downtown_congestion_pricing_in_practice
Natural Resources Defense Council. “What is congestion pricing?” https://www.nrdc.org/stories/what-is-congestion-pricing
San Francisco County Transportation Authority. “Downtown Congestion Pricing.” https://www.sfcta.org/downtown
Bloomberg. “NY Congestion Pricing Plan Violates US Constitution, NJ Governor Says.” https://www.bloomberg.com/news/articles/2024-01-16/ny-congestion-pricing-plan-violates-us-constitution-murphy-says
Federal Highway Administration, Road Diet Case Studies. “Santa Monica, California – Ocean Park Boulevard: Road Diet Improves Safety Near School.” https://highways.dot.gov/safety/other/road-diets/road-diet-case-studies/santa-monica-california-ocean-park-boulevard

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What Is a Vulnerable Road User?

As the transportation industry grapples with the deadly impacts of vehicle-centric infrastructure, new requirements could shift focus onto road users outside the vehicle — vulnerable road users. But what is a vulnerable road user, and can this safety classification actually help agencies save lives?

vulnerable road user blog header with cyclist crossing road

When it comes to road safety outcomes, it’s no surprise that some road users are more vulnerable than others. While drivers are protected by vehicle safety standards and road design that is tailored to their mode of travel, those who walk, bike, or use other forms of transportation often face dangerous roadway conditions, contributing to record high fatality rates for cyclists and pedestrians, even though walking activity is down nationwide. [1]

This safety disparity is nothing new, nor is the term “vulnerable road user,” but up until recently, much of the emphasis on road safety was placed on vehicle safety standards and making roads safe for drivers. Now, transportation professionals are beginning to pay special attention to vulnerable road users as they seek to create safer mobility systems for those outside vehicles.

In a move that underscores the growing attention toward Vulnerable Road Users (VRU), the Federal Highway Administration (FHWA) on February 21, 2024 proposed a change to the Highway Safety Improvement Program (HSIP) regulations, which would require each state to perform a vulnerable road user safety assessment as part of their Strategic Highway Safety Plan (SHSP). And some states, such as West Virginia, have already created Vulnerable Road User risk assessment tools to predict where VRU-related crashes are most likely to occur.

So what exactly is a vulnerable road user, and how can we make them less vulnerable? In this article, we’ll discuss:

What are vulnerable road users?
What is a vulnerable road user safety assessment?
How to make streets safer for vulnerable road users
Data to support vulnerable road users

What Is a Vulnerable Road User?

The National Safety Council (NSC) broadly defines a Vulnerable Road User as anyone not protected by an outside shield (such as the body of a car) while on the road. [2] This definition highlights the increased risk of injury and death road users face in collisions when they are not protected by a vehicle or other “shield.”

More narrowly, the term Vulnerable Road User is typically used to refer to pedestrians and cyclists, but may also apply to motorcyclists, road workers (who are also considered pedestrians), and other road users not inside a vehicle such as a car, truck, or bus.

This classification isn’t merely conceptual. According to data from the National Highway Traffic Safety Administration (NHTSA), VRUs account for a growing and disproportionate share of all traffic fatalities in the U.S., increasing by roughly 1% between 2017 and 2021. [3] This increase happened even while the number of average daily walking trips declined by 36% nationwide between 2019 and 2022, based on StreetLight’s data, underscoring just how dangerous U.S. roadways are for nonmotorists.

cyclists and pedestrians on a shared use path

What Is a Vulnerable Road User Safety Assessment?

A Vulnerable Road User Safety Assessment is a study conducted by a transportation agency — usually a state DOT — to measure safety performance with respect to vulnerable road users. Chiefly, it quantifies fatality and injury rates for VRUs and compares this to overall fatality and injury rates. [4]

A Vulnerable Road User Safety Assessment also requires agencies to identify a set of projects and strategies aimed at mitigating the safety risks faced by vulnerable road users, which could include adding bike and pedestrian infrastructure or reducing speed limits on high-risk roadways. We’ll explore potential safety improvements for vulnerable road users in more detail below.

How to Make Streets Safer for Vulnerable Road Users

To make streets safer for VRUs, it is necessary to go beyond the car-centric paradigm that dominates transportation in the U.S. and build people-first transportation networks that support safe access to all modes of travel.

There are many ways to work toward this paradigm shift and ensure safer streets for all road users, but policy and infrastructure improvements are critical to address the systematic dangers of our transportation networks that make road users vulnerable in the first place.

A Complete Streets policy can encourage planners to identify and address infrastructure gaps that not only impact Vulnerable Road Users, but other groups that face dangerous disadvantages on the road, such as people with disabilities.

Safe Infrastructure for Pedestrians and Cyclists

Safer road infrastructure can take many forms, but a multimodal focus is essential to make streets safer for Vulnerable Road Users. Pedestrian and cycling infrastructure are obvious starting points, since Vulnerable Road Users are primarily walkers and bikers.

Some common infrastructure improvements proven to make streets safer for cyclists and pedestrians include:

Pedestrian islands, widened sidewalks, and bulb-outs
Protected bike lanes, bikeways, and shared-use paths
Signalized crosswalks
Daylighting
Reduced speed limits
Traffic signal retiming
Lane narrowing and lane reductions

For example, in the video below, transportation professionals from Pittsburgh explain how they rebuilt Fern Hollow Bridge to be safer for walkers and bikers after its headline-making collapse in 2022. They did this by adding the city’s first jersey barrier protected bike lanes, lowering the speed limit, and simplifying a complex intersection where drivers were taking risky turns that endangered Vulnerable Road Users.

Similarly, when North Kansas City, Missouri installed a new protected bike lane on Armour Road — a principal thoroughfare running through the city’s downtown and adjacent commercial area — a before-and-after analysis confirmed that the new bike lane boosted bike ridership and reduced vehicle speeds without causing congestion, leading to a safer corridor for Vulnerable Road Users.

Traffic calming measures such as road diets and reduced speed limits can also help address one of the primary factors leading to serious injury and death for Vulnerable Road Users: dangerous vehicle speeds. When ranking speed conditions for the top 30 most populated U.S. metro areas, StreetLight found that among the bottom 25 (those with the most dangerous speeds), 33% of roadways have average vehicle speeds above 35 mph. At these speeds, pedestrians are roughly five times more likely to die from collisions, according to data from the AAA Foundation.

Armour Road with traffic calming measures — *Safety improvements on Armour Rd, North Kansas City including a protected bike lane and painted crosswalk improved safety for Vulnerable Road Users.*

Safe Infrastructure for Other Vulnerable Road Users

The unique needs of motorcyclists and riders of other powered two- and three-wheel vehicles such as mopeds, e-bikes, and e-scooters often get overlooked, even in the context of Vulnerable Road User initiatives.

In fact, some definitions of Vulnerable Road User specifically exclude motorcyclists, such as that put forth by the FHWA in the Vulnerable Road User Safety Assessment Guidance Memorandum issued in October 2022. However, the World Health Organization (WHO) recognizes motorcyclists as VRUs and offers guidance on how to design safer roads for motorcycles. [5]

Safety programs for these road users have typically focused on education and training around defensive driving and the use of Personal Protective Equipment (PPE) like helmets.

But infrastructure is also key to improving safety for these road users. The WHO identifies road design elements such as lane and shoulder width, surface friction, curve type and radius, sight distances, lighting, and turning provisions, including signal phasing at intersections to have significant impact on the severity of motorcycle crashes. Put simply, whenever road design compromises the stability of a motorcycle (such as on sharp curves) or the visibility of motorcyclists (such as poor sight distances or lighting conditions), the risk of severe crashes increases.

motorcycle navigating a turn with no roadside barriers

Exclusive motorcycle lanes have been proven to improve motorcyclist safety, while protected turn lanes, traffic calming measures, and road surface treatments to increase friction are also identified by the WHO as promising countermeasures to reduce crash rates and crash severity for this group.

Other studies also identify the design of guardrails and other roadside barriers, especially along curves, as particularly impactful to motorcycle safety. Motorcyclists account for a disproportionate number of vehicle-guardrail fatalities in the U.S., but there is some evidence that when existing guardrails are retrofitted with a barrier rail below the main guardrail, this can prevent motorcyclists from hitting the supporting poles of a guardrail, making these impacts less fatal. [6]

See how dangerous traffic speeds impact walking and biking in your region

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Data to Support Vulnerable Road Users

Traditional data collection methods like physical roadway sensors and surveys often do not collect data on Vulnerable Road Users, leaving data gaps that can make it difficult to diagnose and address safety issues for VRUs, measure the impact of past infrastructure changes, or even incorporate vulnerable road users into the planning process. While manual counts and surveys directed specifically at pedestrians and cyclists can help fill these gaps, they can also be costly, time-consuming, and subject to bias and sample size issues while also putting agency staff at risk while they are stationed along busy roadways.

Transportation analytics using a big data approach can often offer a more comprehensive and granular view of VRU activity on roadways, while also providing insights into vehicle speed, volumes, and other factors impacting VRU safety.To diagnose dangerous roadway conditions Vulnerable Road Users face in your region, the following metrics can be helpful:

Vehicle Speeds – to understand where unsafe speeds put VRUs at the highest risk of fatal crashes
Active Transportation Activity – to map and measure VRU exposure and prioritize corridor improvements
Vehicle Volumes – to further contextualize VRU exposure and understand how potential road design changes may impact capacity and congestion
Turning Movement Counts – to understand safety conditions at intersections, where most collisions occur

Before-and-after analyses of each of these metrics can also help evaluate the success of past projects, justify funding requests, and gain public or political support for future improvements.

For example, a StreetLight analysis of Oakland’s Grand Avenue used data on vehicle speeds, pedestrian activity, and routing patterns to show that a road diet could help improve safety on this corridor without causing congestion.

In Pittsburgh, analysts also overlaid bike and pedestrian activity onto crash data to understand the factors that lead to crash severity and prioritize equitable safety improvements throughout the city.

The video below provides a helpful introduction to how agencies can use these sorts of analyses to diagnose dangerous conditions and prioritize safety investments.

For a comprehensive guide to transportation safety analytics, download our Practitioner’s Guide to Transportation Safety.

Insurance Institute for Highway Safety, “Fatality Facts 2021, Pedestrians.” May 2023. https://www.iihs.org/topics/fatality-statistics/detail/pedestrians
National Safety Council. “Position/Policy Statement, Vulnerable Road Users.” https://nsc.org/getattachment/d5babee6-582d-4e66-804f-8d06f9b021a4/t-vulnerable-road-users-147
National Highway Traffic Safety Administration. “National Statistics.” https://www-fars.nhtsa.dot.gov/Main/index.aspx
Federal Highway Administration. “Vulnerable Road User Safety Assessment Guidance.” https://highways.dot.gov/safety/hsip/vru-safety-assessment-guidance
World Health Organization. Powered two-and three-wheeler safety: a road safety manual for decision-makers and practitioners. 9 October 2022. https://www.who.int/publications/i/item/9789240060562
Georgene M. Geary, Infrastructure Measures to Protect the Unrecognized Vulnerable Road User: Motorcyclists. Eng. Proc. 2023, 36, 36. https://doi.org/10.3390/engproc2023036036

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6 Ways to Drive Sustainability in Transportation

bicyclist on trail through lush natural scenery

Sustainability may be a marketing buzzword, but the concept has never been more critical in transportation. As climate change continues to charge forward, shifting our behaviors, habits, and societal systems to preserve and pass on a healthy environment is one of the most pressing challenges of our time.

Rethinking how we get around is a crucial aspect of this challenge. The transportation sector is responsible for more greenhouse gases (GHGs) — a leading driver of climate change — than any other sector in the United States. [1]  Small changes in this area, when multiplied by millions of people in major urban areas, could dramatically reduce emissions and create a more sustainable lifestyle for future generations.

For sustainability to be more than a mere buzzword, however, we must move past using it as a marketing term and find sustainable transportation solutions that can truly move the needle in the fight against climate change. In this article, we’ll cover six key ways to drive sustainability in transportation, including:

Promote electric and hybrid vehicles
Invest in public transportation infrastructure
Prioritize sustainable urban planning
Implement smart traffic management systems
Support active transportation modes
Develop sustainable freight transport systems

Promote Electric and Hybrid Vehicles

The data is clear: Over the full vehicle lifecycle, hybrid and electric vehicles (EVs) produce far lower levels of GHG emissions than gas-powered cars. This is true even when accounting for the varying sustainability of fuel sources used to produce electricity. According to data from the Alternative Fuels Center, the average hybrid vehicle produces 55% as much emissions over its life as a similar gas-powered vehicle. The typical electric vehicle, meanwhile, produces 22% as much emissions as a gas car. [2]

Harnessing these benefits at scale requires significant investment into electric and hybrid vehicle technologies. Altogether, EVs and hybrids represented 16% of U.S. light-duty vehicle sales in 2023 — a significant amount, but far from unseating gasoline as the primary source of fuel. [3]

Federal and state programs provide tax credits or other incentives to encourage EV adoption and EV charger installation, but more programs are needed to overcome consumer concerns about battery range and costs of ownership. Local governments can explore additional incentives and work with utility companies to support rebate programs for EV chargers and bolster the electrical grid to handle growing charging demands. Additionally private and public organizations must step up to lead the charge in electrifying fleets and offering public charging options. More research and investment in other alternative fuels, such as biofuels, propane, and natural gas, could also help cut into the market share of gasoline. [4]

massachusettes EV Charging infrastructure Gaps — *A map of EV charging gaps in Massachusettes highlights where more charging infrastructure may still be needed to meet rising demand.*

Invest in Public Transportation Infrastructure

Public transportation is a multi-faceted sustainable transportation solution. Not only does it reduce GHG emissions — by as much as two-thirds compared to private vehicles — but it also drives sustainability in more holistic ways. For instance, a stronger public transportation infrastructure provides more equitable access to jobs, education, and services, raising the standard of living for some of the most disadvantaged members of society. It also promotes a more active lifestyle and reduces communities’ exposure to pollutants, both of which can improve health outcomes across the board. [5]

Urban planners can use transportation data to find ideal opportunities for enhancing public transportation, whether by adding more light rail or expanding bus routes. For instance, planners with TransLink in Vancouver, B.C. used data comparing commuter reliance on various modes of transportation to demonstrate the strength of existing bus ridership across the metro area. With such detailed data on various urban corridors, planners were able to make the case for greater investment in bus transportation throughout the region.

Support Active Transportation Modes

Active methods of transportation, such as biking and walking, also tackle the sustainability problem from multiple angles. Communities with higher levels of active transportation are happier and healthier, and biking and walking can drastically reduce emissions. Even choosing to ride a bike instead of driving once a day can reduce one person’s emissions by as much as 67%. [6]

However, far too few U.S. cities are designed with cyclists and pedestrians in mind. To see more commuters make these choices, planners must make streets safer and routes more direct for active modes of transportation. That means expanding bike lanes, adding sidewalks and crosswalks, and reducing the width of certain streets. Similarly, cities would benefit from development approaches that increase population density and support shorter commutes by placing essential services within biking and walking distance.

Once again, deciding on the best options for such changes requires an in-depth analysis of available traffic data. Understanding current traffic patterns can help planners pinpoint, for instance, where a road diet may help to divert or slow traffic and make room for a new bike lane. Or, as planners did in Portland, Oregon, cities can examine the data on average trip distance to find opportunities for adding safer active transportation options such as pedestrian bridges or strategic walking paths.

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Implement Smart Traffic Management Systems

Not every transportation improvement requires a major overhaul. Some sustainable transportation solutions are simple, especially with the technology and data available today. Smart traffic management systems leverage tools like signal timing, traffic cameras, and automated speed enforcement to improve traffic flow and reduce pollution from congestion and extended travel times. By reducing both extreme speeds and heavy idling, transportation planners can help improve fuel efficiency and lessen overall pollution. [7] These simple tools can also decrease speeding and related accidents, making transportation more sustainable in other important ways. [8]

Transportation planners and agencies can use detailed traffic data to find the best opportunities for these types of smart traffic solutions. For instance, higher traffic counts or average speeds at a specific intersection could warrant camera-enforced radar or improvements in signal timing methods.

Develop Sustainable Freight Transport Solutions

According to the EPA, large trucks are already the fastest-growing contributor to transportation emissions. On top of that, shipments of U.S. goods are expected to increase by 40% by 2040, pushing the growth of emissions from freight ahead of all other transportation categories over the next 15 years. [9] In other words, you can’t address the sustainability of transportation without considering the role of freight transport.

Transitioning more fleets to electric or alternative fuels could substantially increase sustainability in this sector, especially for delivery vehicles that travel fewer than 200 miles per day. [10] Additionally, a significant portion of freight emissions come from poor route planning and wasted miles — areas that can benefit from data analysis around metrics like trip length, travel time, and hours of delay. By making delivery routes more efficient, large companies can offset some of the impact of this growing portion of the transport sector.

Prioritize Sustainable Urban Planning

Cities account for between 60% and 80% of the world’s energy consumption and 75% of emissions, despite only occupying about 3% of its land. [11] Transportation may be one of the biggest contributors to urban emissions and energy usage, but it’s by no means the only one.

That said, transportation is linked to numerous other aspects of urban planning, and connecting transport and sustainability ultimately requires a broader approach to all aspects of city planning. For instance, transportation planners can think beyond the mechanics of roadways to consider how adding green spaces to urban corridors can enhance quality of life and improve air quality by adding more trees.

Likewise, urban planners must dive into transportation data to understand how a new development would affect traffic patterns and potentially help or harm larger sustainable development goals. Clear data on the traffic volume in a given corridor, for example, may help planners decide whether a road diet will ease or exacerbate traffic and pollution.

What Is the Future of Sustainable Transportation?

Setting the stage for greener transport is a critical component of the environmental movement. Without sustainable transportation, it’s difficult to imagine a sustainable future.

The good news is that there are several ways to make the transport sector more sustainable. And with big data at the center, planners can ensure these efforts achieve their maximum impact by making informed decisions about which initiatives are most urgent for their region.

Big data platforms like StreetLight InSight® provide valuable, actionable data that planners can use to evaluate vehicle emissions and understand how infrastructure changes could transform their area. With access to detailed metrics on origin and destination, vehicle volume, speed, turning movements, and more, you can look at potential solutions from every angle, both in terms of safety and sustainability.

In the video below, you can see how transportation professionals in Maine used these kinds of metrics to measure regional transportation emissions and equip cities and counties with data to inform local emissions reduction efforts.

To learn more about StreetLight’s methodology for measuring GHG emissions, and how StreetLight InSight® can help you capture this key data, check out our recent white paper.

And to see where your city ranks on eight major factors that contribute to transportation emissions, download our free eBook, Transportation Climate Impact Index: How the top 100 U.S. metros rank on core emissions factors.

U.S. Environmental Protection Agency. “Fast Facts on Transportation Greenhouse Gas Emissions.” https://www.epa.gov/greenvehicles/fast-facts-transportation-greenhouse-gas-emissions
Alternative Fuels Data Center. “Emissions from Electric Vehicles.” https://afdc.energy.gov/vehicles/electric-emissions
U.S. Energy Information Administration. “Electric vehicles and hybrids surpass 16% of total 2023 U.S. light-duty vehicle sales.” https://www.eia.gov/todayinenergy/detail.php?id=61344
University of Minnesota Transportation Futures Project. “Alternative Fuels & Vehicle Electrification.” https://www.minnesotago.org/application/files/5614/6376/6119/AlternativeFuels.pdf
World Resources Institute. “3 Ways to Reimagine Public Transport for People and the Climate.” https://www.wri.org/insights/3-ways-reimagine-public-transport-people-and-climate
UCLA. “How Riding A Bike Benefits the Environment.” https://www.wri.org/insights/3-ways-reimagine-public-transport-people-and-climate
Northeast Ohio Areawide Coordinating Agency. “Impacts of Idling.” https://www.noaca.org/regional-planning/air-quality-planning/transportation-emissions/impacts-of-idling
U.S. Department of Transportation. “ITS Fast Facts.” https://www.its.dot.gov/resources/fastfacts.htm
U.S. Environmental Protection Agency. “Why Freight Matters to Supply Chain Sustainability.” https://www.epa.gov/smartway/why-freight-matters-supply-chain-sustainability
Alternative Fuels Data Center. “Electric Vehicles for Fleets.” https://afdc.energy.gov/vehicles/electric-fleets
United Nations Foundation. “5 Statistics on Why Urban Development Matters.” https://unfoundation.org/blog/post/5-statistics-on-why-sustainable-urban-development-matters/

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How Should We Build EV-Charging Infrastructure?

Electric vehicles (EVs) are a critical element of the fight against climate change. Compared to a typical gas-powered vehicle, the average EV produces less than half the amount of carbon pollution over its lifetime. [1] Even at today’s moderate levels of EV sales, electric cars are already reducing crude oil usage by 1.7 million barrels a day. [2]

Yet we have a long way to go to reach the tipping point, when EVs take over as the primary form of individual transportation. In the U.S., 10% of new vehicles registered in 2023 were electric, far from a majority. [3] Tipping the scales requires not only an increase in EV production, but a significant expansion of the nation’s EV charging infrastructure.

As of today, our systems are woefully underprepared for an EV-dominant future. What will it take to catch up? Although federal and state-level funding is essential, building an adequate charging infrastructure largely comes down to smart, data-driven planning.

In this article, we’ll explore what that looks like, covering the following:

How do EV charging stations work?
The current state of EV charging infrastructure
Optimizing charger placement in communities
Promoting sustainable energy sources

How Do EV Charging Stations Work?

Electric vehicle supply equipment (EVSE), as charging stations are commonly called, is fundamentally different from gas pumps. While both types of equipment are designed to refuel vehicles, EV charging stations are far less standardized than gas pumps.

EVSE comes in several different types, from basic (extremely slow) Level 1 chargers to high-speed, Level 3 DC fast chargers. Although the latter can recharge an empty car battery to 80% in less than an hour, most public EVSE consists of Level 2 chargers, which take anywhere from four to 10 hours to achieve a similar charge level. [4]

Not surprisingly, EV charging station costs vary widely based on type. You can plug into your home outlet for Level 1 charging, but it’ll cost anywhere from $1,000 for a basic home Level 2 charger to upwards of $50,000 for a commercial Level 3 charger. [5], [6]

Besides the cost of EV charging stations, planners must consider numerous other factors, including the connection type, interoperability with various vehicles, and the payment network of choice. All of these are critical factors in how to build EV charging station infrastructure.

The Current State of EV Infrastructure

In the U.S., the number of public and private EV charging stations has grown rapidly in recent years, thanks largely to available tax credits and incentives to help reduce upfront costs. However, the nation’s EV charging infrastructure has a long way to go to keep pace with near-term goals for vehicle electrification.

That’s especially true for public EVSE. Recent research by Stanford University sounded the alarm that relying on nighttime, home-based charging would put far too much demand on the electrical grid within the next decade. [7]

Currently, there are almost 10 times more home EV chargers than public ones, and that ratio needs to change quickly. [8] Data from the National Renewable Energy Laboratory (NREL) further supports the need for a massive uptick in public charging station installations. As of 2023, there were just over 168,000 public charging ports available in the U.S., but NREL research calls for nearly 1.2 million public ports to match EV demand by 2030.[9], [10]

It’s not just a numbers game, either. If electric vehicles are to become the norm, EV charging station infrastructure must be more accessible to everyone. That means charging equipment must become more interoperable with all types of EVs, stations must be available where people can conveniently use them, and EVSE must be reliable and easy to use.

Overall, reaching this level of accessibility requires more investment in both public and private (workplace) charging, along with a commitment to eradicating “charging deserts” in underserved communities. [11]

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Optimizing Charger Placement in Communities

The long-term goal may be accessible, reliable charging for everyone, but we are still many miles from that final destination. Accelerating our progress in the right direction requires near-term prioritization. Where does a given community need EV charging infrastructure next? What locations would make it practical and easy for more existing EV drivers to switch from charging at home overnight to charging at work or while shopping during the day?

To understand that, planners must gather and analyze a host of data. Targeting the ideal location for more EV chargers involves analyzing demographics and demand, accessibility concerns, and mobility patterns in various communities. It also requires an understanding of existing infrastructure and the differing needs of rural and urban locations.

For instance, planners in a dense urban area may need to evaluate traffic patterns in numerous parts of the city to understand how far people commute every day, where they tend to stop and for how long, and where people without driveways tend to park. In a rural area, conversely, data about long-range commutes and the most trafficked freeway corridors may be more relevant. They might also examine data about interstate corridors with heavy commercial freight transit to find ideal hubs for charging heavy-duty vehicles.

In the Silcon Valley, for example, planners used StreetLight InSight® to evaluate Origin-Destination (O-D) data, traveler demographics, and more to help choose locations for 400+ public EV chargers.

Planners must also attack the problem at a broader level, considering factors like how a specific location for EV charging stations will affect electricity demand in a particular area.

To prepare the electric grid for rising EV charging demand, Eversource, New England’s largest utility, used StreetLight to forecast where and when charging demand would be highest to plan substation upgrades and charging rates that would incentivize off-peak charging. Their demand analysis also allowed them to coordinate long-term electrification planning with public agencies.

Promoting Sustainable Energy Sources

Taking a wider scope, examining the best locations to maximize the impact of clean transportation can help planners prioritize where and how to build EV charging infrastructure. Although EVs reduce emissions regardless of where you deploy them, they offer the largest reduction in regions that rely on clean energy sources like wind, solar, or hydroelectric power.

For example, driving an EV in a coal-dependent state like West Virginia results in a 50% reduction in emissions compared to driving a gas car. In Texas, which is a national leader in solar and wind power generation, choosing an EV reduces emissions by over 77%. [12]

Practically, the application here is twofold: On one hand, it may be beneficial to develop more EV charging infrastructure in areas that already rely on clean energy sources. Yet, it’s also likely worth considering policies and incentive programs that will help municipalities and private companies go beyond simply installing EVSE to adding solar panels, wind turbines, or other clean energy sources that increase EVs’ environmental impact.

Get Charged Up With Big Data

EV charging infrastructure has come a long way in the U.S.—but there’s still a long road ahead to add enough EVSE to support a truly all-electric transportation system. Reliable data is crucial at this stage, regardless of where you’re looking to add more charging equipment. The pressing issue doesn’t simply come down to adding more chargers, but knowing where to put them so that they best serve real-world demand efficiently and equitably.

With purpose-built EV metrics and emissions analytics, StreetLight InSight® can help planners, policymakers, and businesses make smart decisions in this crucial sector. This software unlocks access to relevant transportation data, including O-D, vehicle miles traveled, traveler demographics, travel times, and more. This helps pinpoint where people are traveling and when traffic is highest to measure the potential GHG impact of adding EV charging stations to any specific location, while ensuring the grid can handle rising electric demand.

See how it works in the video below.

To learn more about how you can use big data to fight against climate change, download our Transportation Climate Data Solutions handbook.

To start using StreetLight to plan your EV charging infrastructure today, contact us here.

Yale Climate Connections. “Don’t get fooled: Electric vehicles really are better for the climate.”
BloombergnNEF. “ElectricVehicle Outlook 2024.”
International Energy Agency. “Global EV Outlook 2024: Trends in electric cars.”
U.S. Department of Transportation. “Charger Types and Speeds.”
J.D. Power. “What Does an EV Home Charger Cost?”
State of New York. “Exhibit I Cost of charging stations.”
Stanford University. “Charging cars at home at night is not the way to go, Stanford study finds.”
International Energy Agency. “Global Outlook 2024: Trends in electric vehicle charging.”
National Renewable Energy Laboratory. “The 2030 NationalCharging Network: Estimating U.S. Light-Duty Demand for Electric Vehicle Charging Infrastructure.”
Alternative Fuels Data Center.  ”U.S. Public Electric Vehicle Charging Infrastructure.”
World Resources Institute. “Many US Communities Face EV ‘Charging Deserts.’ 5 Strategies Can Help.”
Alternative Fuels Data Center. “Emissions from Electric Vehicles.”

traffic on highway interchange used for aadt calculation

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What Is a Road Diet? The Data Behind How They Work and How To Implement Them

By removing or repurposing one or more lanes of traffic, road diets promote positive mobility outcomes from improved safety to reduced emissions. But despite proven success, some find the approach controversial.

What is a Road Diet header image - two-lane street with bike lanes

Since the 90s, road diets have become a popular tactic to calm traffic and implement multimodal transportation options. But planners and advocates often face resistance from those who are worried that fewer lanes will lead to more congestion.

A road diet reconfigures an existing roadway by removing or repurposing lanes devoted to vehicle traffic. The overall impact is typically fewer cars on the road and reduced travel speeds, often for the relatively low cost of restriping.

The most traditional version of a road diet reduces the total number of lanes on a roadway by converting one or more lanes into a central turn lane that both traffic directions can use to make left turns.

Other types of road diets might convert one or more existing lanes into bike lanes, bus-only lanes, medians, sidewalks, or landscaping.

And in spite of the concerns often raised by public and political stakeholders, road diets have stood the test of time. According to the FHWA, they have been in use for more than three decades, with one of the first installations dating back to 1979 in Billings, Montana. Since then, they’ve improved safety and mobility outcomes for roads in Charlotte, Chicago, New York, San Francisco, and many other cities across the U.S. [1]

Road diets have been gaining more attention since the pandemic as biking activity increased. Simultaneously, speeds have also increased, creating dangerous conditions for those in vehicles as well as those on foot or bike. According to the National Highway Traffic Safety Administration (NHTSA), there were over 6,000 pedestrian fatalities in 2020, a 3.9% increase from 2019, while pedestrian injuries rose 28% from 2019 to 2020. [2]

Meanwhile, the Bipartisan Infrastructure Law (BIL) has put a special focus on safety infrastructure, establishing grant programs like Safe Streets and Roads for All (SS4A). The U.S DOT webpage on the SS4A grant program lists road diets under their examples of eligible low-cost safety treatments for Implementation Grant funding. [3]

But why do road diets work, and what makes them a popular tactic for many DOTs, MPOs, and other public agencies? In this post, we’ll cover:

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How Does a Road Diet Improve Safety?

Speed is among the primary factors in road safety, with higher speeds leading to more severe crashes. That’s one reason why road diets are so effective in improving safety for all road users.

With multiple lanes in each direction of travel, drivers are quick to speed up and pass other vehicles, hoping to get to where they’re going as quickly as possible. Adding to the problem, roads with little to no multimodal infrastructure signal to drivers that there is no need to slow down for more vulnerable road users such as pedestrians, cyclists, or road workers.

According to the FHWA,

Four-lane undivided highways experience relatively high crash frequencies — especially as traffic volumes and turning movements increase over time — resulting in conflicts between high-speed through traffic, left-turning vehicles and other road users. FHWA has deemed Road Diets a proven safety countermeasure and promotes them as a safety-focused design alternative to a traditional four-lane, undivided roadway. [4]

In fact, FHWA studies of road diet projects have found that reducing the number of lanes dedicated to cars reduces crashes by 19 to 52% due to reduced speeds and fewer opportunities for collisions. [5]

When a road diet repurposes the existing space for multimodal or more accessible infrastructure such as widened sidewalks, bike or bus lanes, or pedestrian safety islands, they also use Complete Streets principles to make the roadway safer for all road users, regardless of their mode of travel.

The overall effect of reducing vehicle lanes and reclaiming space for non-vehicle modes is traffic calming. By encouraging slower driving and less vehicle throughput, road diets reduce exposure for Vulnerable Road Users and lessen the severity of crashes that do occur.

How Does a Road Diet Reduce Vehicle Traffic?

People often worry that removing lanes will just make driving more miserable. After all, fewer lanes means less road capacity for cars, creating bottlenecks where traffic could once flow freely. At least, that’s the concern.

But in reality, road diets rarely lead to increased congestion. There are a few reasons why.

The first has to do with reduced demand. You may have heard that increasing the number of lanes on a highway often has the paradoxical effect of increasing congestion. That’s because adding lanes induces demand, leading more people to choose to drive on that roadway. By the same token, removing lanes actually reduces demand. But where do those travelers go?

Some traffic may reroute to nearby roadways while other drivers may choose to travel via other modes. After all, with fewer cars and lower travel speeds, the road is now safer for pedestrians and cyclists. Especially so if the lanes have been repurposed for multimode infrastructure like bike lanes or sidewalks. Likewise, a road diet might repurpose an existing lane for bus-only traffic, incentivizing more travelers to use public transit options that reduce the number of vehicles on the road.

In one road diet example on Ocean Park Blvd in Santa Monica, California, the city restriped 4 lanes of roadway into 3 lanes including a central left turn lane, plus added bike lanes in both directions. While there was public concern that traffic would reroute to nearby roadways like the I-10, a study of traffic counts showed volumes on nearby roadways remained relatively stable. Meanwhile, there was a 65% reduction in crashes after the road diet was implemented. [6]

a bus-only lane on an urban road — *A bus-only lane incentivizes more travelers to choose public transit in NYC.*

How Does a Road Diet Cut GHG Emissions?

By reducing the number of cars on the road, road diets also reduce overall Vehicle Miles Traveled (VMT), leading to local reductions in greenhouse gas (GHG) emissions.

The potential for a road diet to reduce emissions is enhanced when lanes are repurposed for multimodal infrastructure that encourages climate-friendly travel options like walking, biking, and public transit.

Plus, when road diets are used as a traffic calming measure — i.e., to reduce overall traffic speeds — they may also reduce fuel consumption and thereby reduce emissions. This is because cars are less fuel efficient and produce more CO2 per mile traveled when traveling at higher speeds.

For example, in the video below, the Southern Maine Planning & Development Commission explains how they used VMT and Origin-Destination analyses in StreetLight InSight® to measure local GHG emissions. What they learned helped them plan regional reduction strategies, including multimodal infrastructure that would reduce VMT.

Real Road Diet Examples and the Data Behind Their Success

To plan an effective road diet, you first need to get the full picture on travel behaviors. Traditional data collection methods like sensors and surveys can help planners measure existing conditions like roadway volumes, travel speeds, and turning movements.

But many roads lack permanent sensors, and temporary sensors and manual counts only get a snapshot of roadway conditions, so planners may miss how conditions change over the course of the day, week, or year. Likewise, surveys suffer from low sample sizes and can be expensive and time-consuming.

Pairing traditional data collection methods with on-demand transportation analytics gathered through connected vehicles and the Internet of Things can help fill data gaps to not only plan new road diets but also evaluate the success of existing road diets, offering historical data for before-and-after studies.

For example, in the video below, Maine DOT explains how they used StreetLight’s traffic data including Turning Movement Counts, Origin-Destination analyses, and roadway volume in their modeling efforts to help evaluate safety and mobility outcomes for a proposed road diet on Bangor Street that would reduce traffic to one lane in each direction.To find good candidates for road diets, Annual Average Daily Traffic (AADT) and Vehicle Miles Traveled (VMT) can be used to identify high-volume roadways and segments where road diets may be the most impactful.

Pairing these insights with travel speeds, crash reports, and pedestrian and cyclist activity is a crucial next step to illuminate where volume is high and safety is low, revealing high-priority locations for potential road diets that could save lives.

Turning Movement Counts (TMC) at intersections along a corridor can also help determine whether a traditional road diet (turning existing lanes into a center, two-way left-turn lane) may ease traffic flow.

To understand how a road diet may impact traffic on nearby roadways, Origin-Destination and Top Routes analyses can help pinpoint where cars and trucks may reroute, giving planners the opportunity to ensure sufficient capacity on nearby roads, especially if the road diet does not include plans to add multimodal infrastructure.

To evaluate the impact of a road diet, before-and-after studies measuring changes in overall roadway volumes, safety outcomes, and congestion metrics like Vehicle Hours of Delay (VHD) can help ensure a road diet is achieving its desired outcomes and provide justification for future road diet projects.

Since road diets often face resistance, quantifying the success of past road diets and showing how you will measure traffic impact can help answer constituent concerns around travel time impact.

For example, in 2019, Armour Road in North Kansas City, Missouri underwent a series of improvements, including the addition of a new protected bike lane and pedestrian refuges. A before-and-after study by StreetLight shows a significant reduction in dangerous vehicle speeds, double the biking activity, and a negligible increase in travel times (around five seconds on average) along the corridor.

Metrics to Measure Traffic Volume and Roadway Capacity

– AADT, VMT

To find good candidates for road diets, Annual Average Daily Traffic (AADT) and Vehicle Miles Traveled (VMT) can be used to identify high-volume roadways and segments where road diets may be the most impactful.

Metrics to Diagnose Road Safety Risks

– Travel speeds, crash rates, pedestrian & cyclist activity

Pairing traffic volume insights with travel speeds, crash reports, and pedestrian and cyclist activity is a crucial next step to illuminate where volume is high and safety is low, revealing high-priority locations for potential road diets that could save lives.

Metrics for Planning Road Diet Implementation

– TMC, O-D, Top Routes

Metrics to Measure Road Diet Success

– Changes in VHD, AADT, VMT, travel speeds, crash rates, O-D, Top Routes, bike and pedestrian activity, and more

To evaluate the impact of a road diet, before-and-after studies measuring changes in overall roadway volumes, traffic routing, safety outcomes, and congestion metrics like Vehicle Hours of Delay (VHD) can help ensure a road diet is achieving its desired outcomes and provide justification for future road diet projects.

Since road diets often face resistance, quantifying the success of past road diets and showing how you will measure traffic impact can help answer constituent concerns.

When road diet proposals spark public outcry, congestion and travel time are typically peak concerns, but residents may also cite safety concerns like increased emergency response times or economic impacts on nearby businesses due to reduced traffic and parking availability. In these cases, analyzing multimodal activity that could boost visits to businesses and nearby road capacity that can accommodate emergency services rerouting could also help assuage concerns.

armour road travel speed data after road diet — A visualization from StreetLight InSight® of average speed on Armour Road in the 2021 study period shows how the bike lane curtailed speeding. There are very few instances of vehicles traveling above 40 mph (shown in green) when that proportion was much higher before, about one in every 20 trips.

To learn more about how on-demand transportation data can enhance safety planning, download our free Safety Data Handbook.

U.S. DOT Federal Highway Administration. “Road Diets (Roadway Reconfiguration).” October 25, 2022.
NHTSA. National Pedestrian Safety Month 2022 Resource Guide. October 2022.
U.S. DOT, “Safe Streets and Roads for All (SS4A) Grant Program.” April 26, 2023.
U.S. DOT Federal Highway Administration. “Road Diets (Roadway Reconfiguration).” October 25, 2022.
Andrew Keatts, Rice University Kinder Institute for Urban Research. “What Are ‘Road Diets,’ and Why Are They Controversial?” September 10, 2015.
Federal Highway Administration, Road Diet Case Studies. “Santa Monica, California – Ocean Park Boulevard: Road Diet Improves Safety Near School.”

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What’s the Quickest Way to Solve a City’s Traffic Congestion?

What's the Quickest Way to Solve a City's Traffic Congestion?

Traffic congestion is one of the most persistent problems facing modern drivers. According to the Texas A&M Transportation Institute, the typical U.S. driver loses 54 hours a year (about an hour each week) to congestion. This costs the average commuter over $1,100 annually. [1]

These losses, along with safety concerns associated with increasing urban congestion, make finding solutions for traffic congestion a critical task for transportation planners and community stakeholders. As populations grow and commute distances increase, the problem only promises to grow worse without intervention.

Once you begin to dig into the causes of traffic congestion, however, it quickly becomes clear that this is a complex issue. Although adding lanes to roadways has often been treated as a silver bullet to address limited capacity, this has often been shown to compound existing congestion in the long term by inducing demand. In reality, there’s no quick fix for overcrowded urban roadways, and effective congestion reduction often requires a multi-pronged approach. Nonetheless, when planners and agencies can analyze a range of data and uncover the real causes of congestion in their area, they can pave the way for more free-flowing and safer roads.

Below, we’ll explore this challenge in detail, covering:

What can cause city traffic congestion?
Narrowing down causes case by case
Traffic congestion solutions
Fixing traffic congestion problems with a multi-pronged approach
Undoing urban congestion with big data

What Can Cause City Traffic Congestion?

Finding adequate traffic congestion solutions first requires a thorough understanding of the potential causes involved in any given region, and these vary by the type of area — urban or rural. For a broad overview of these contributing factors, planners often refer to the Federal Highway Administration’s (FHA) “sources of congestion” estimates, which break down the primary causes for urban and rural areas as follows: [2], [3]

These are national averages, and the specifics vary significantly from one urban or rural area to another. The Texas A&M Transportation Institute has conducted extensive research on traffic congestion causes in several urban areas, and the data shows that the prevalence of specific causes can be quite different even within the same region. For example, roadwork is responsible for 26% of urban traffic congestion incidents in Pittsburgh’s 11th District, but only 17% of incidents in Philadelphia’s Sixth District. [2]

Moreover, focusing only on these categories would severely limit our understanding. Traffic congestion is exacerbated by uniquely 21st-century issues, some of which aren’t yet reflected in the FHA data. For instance, research points to six additional factors that contribute to congestion:

Economic expansion
Demographic changes and urbanization
Transportation disruption from ride hailing and Transportation Network Companies
E-commerce and on-demand delivery
Insufficient infrastructure investment
Mixed effectiveness of current congestion solutions [4]

Given that each of these factors is multifaceted in its own right, it’s safe to say that congestion is a complex problem requiring a diverse array of solutions.

The Consequences of Congestion

If the causes of congestion are difficult to sort out, its consequences are even more so. Some results are more obvious than others. As previously noted, it’s easy enough to extrapolate the costs of congestion on an individual level. When U.S. drivers spend about an hour each week dealing with traffic jam problems or other slowdowns, the costs add up in terms of time and fuel.

Even more troublesome is the connection between congestion and accidents. Research results vary, and the exact relationship between the two isn’t entirely clear. However, the best data seems to support a bell-shaped curve, where accidents occur most frequently in low-traffic and high-traffic situations. The former is likely due to higher speeds on open roadways, while the latter is likely related to the volume of traffic. [5]

More research is needed to better explain these connections, but it’s clear that congestion and accident volume are related, making congestion not merely an issue of cost and convenience but also road safety.

Narrowing Down Causes Case by Case

To gain a more precise understanding of the causes and consequences of traffic congestion, planners and other stakeholders need a clearer picture of what’s happening on the roadways in their regions. No two regions are the same, and finding unique solutions requires a granular analysis of how each factor is shaping outcomes in a particular area.

The Role of Data

Leveraging data allows planners to get to the underlying issues creating traffic congestion. It encourages a deeper exploration of potential causes, such as:

Sources and destinations of traffic
Participants in the traffic jam and their reasons for being on the road
Daily and weekly time trends
Alternative routes or transportation options

Armed with tools for collecting traffic data, planners can find more precise reasons for congestion — and plan better solutions to the problem. Only with detailed analysis can the discussion move from generalities to actionable specifics and avoid falling back on tired, ineffective traffic congestion solutions.

time lapse of super bowl traffic congestion — *A time lapse showing traffic congestion near Allegiant Stadium in Las Vegas, NV during the 2024 Super Bowl. Higher volumes appear in red, while lower volumes are in blue.*

What Doesn’t Work to Decrease Congestion?

Historically, urban planners resorted to a one-size-fits-all solution for traffic congestion: Add more lanes. It seems obvious — more space for cars should lead to less cramped corridors, right?

Ultimately, the answer is no. Adding lanes has often been shown to induce even greater demand, inviting more traffic in the long run. Rather than targeting what’s pushing traffic into the area, this approach makes room for even more drivers to flood the congested space. Without a more obvious alternative, drivers will simply gravitate toward the expanded roadway.

Additionally, expansion is expensive  — $15 million per lane on average as recently as 2014, according to the Highway Economic Requirements System. Lane construction also causes additional congestion, resulting in significant delays during the project. Ultimately, this approach falls short of addressing larger concerns of public health, safety, and equity, because it fails to ask deeper questions about why heavy traffic is present to begin with.

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Traffic Congestion Solutions

When they’re able to conduct a robust analysis, planners often find that the answers are entirely different than what they anticipated. While there are many potential courses of action, data points to five particularly effective solutions for urban congestion.

Improving Traffic Flow

There are numerous ways to improve traffic flow, and the right options depend on the nature of the congestion problem at hand. The Texas A&M Transportation Institute provides several solutions, including intersection improvements, loop ramps to reduce left turns, and designated lanes for high-occupancy vehicles or public transit. [6]

The key to choosing the best option is to explore traffic data to find out where the bottlenecks are coming from. For example, planners in Shreveport, Louisiana, were able to leverage data to find precise solutions to congestion problems in their region. By closely examining 158 miles over six corridors, they determined where the greatest speed reductions were occurring and pinpointed six miles with severe congestion. This information led them to tangible solutions, such as intersection signage, highway on-ramp signaling, and expanded capacity in select corridors.

Road Diets

Another highly effective way to manage traffic congestion is to implement what are known as “road diets.” This is the opposite approach from adding lanes — instead, it reduces available driving lanes in favor of center turn lanes, bike lanes, bus lanes, landscaping, or other uses.

While this may seem counterintuitive, road diets have been shown to reduce traffic and accidents when properly implemented. To find good candidate corridors and choose the right solution, city planners must examine key metrics such as Annual Average Daily Traffic (AADT), Vehicle Miles Traveled (VMT), and Turning Movement Counts (TMC), in addition to measurements of pedestrian and bicycle activity. By understanding the exact nature of area traffic flows,  planners gain invaluable insights into what road diet approach would be most effective.

Travel Demand Management

In many cases, the ideal way to address traffic jam problems is to reduce car travel demand in the affected area and increase the use of other methods such as public transit or cycling (this is part of why road diets that add infrastructure for cyclists, pedestrians, or transit can be effective congestion mitigation tactics). This approach examines the sources of traffic and readily available alternatives that may redirect, reduce, or replace it.

One region, in particular, provides a pointed case study for this solution. Napa Valley planners were surprised when traffic data revealed that congestion was a result not of tourists and pass-through commuters, but of employees driving into the area for work. This information transformed their approach to congestion mitigation, directing them to focus on optimizing bus routes and building affordable housing for workers to move to the area.

Congestion Pricing

Congestion pricing involves the use of tollways to discourage some drivers from using certain roadways. An effective — albeit controversial — option for solving traffic problems, tollways transfer more of the responsibility to those who use the roadways. It invites them to consider whether the convenience of the route is worth the extra cost. Unlike fuel taxes, which penalize all drivers indiscriminately, tollway pricing charges drivers for the miles they drive in highly congested areas. Similarly, high-occupancy vehicle (HOV) lanes can charge vehicles with low occupancy to use them while allowing HOVs to pass free of charge.

Before implementing congestion pricing, deep data analysis is required. Planners should evaluate area demographics, traffic sources and destinations, public transit options, and more. When done correctly, such a program can reap big rewards for the region. After implementing a form of congestion pricing (and making other improvements) along IH-10 and IH-110, Los Angeles saw bus ridership increase between 27% and 37% in those areas, reducing the proportionate number of cars on the road.7

Expanded Transportation Options

Transportation planners must also think more broadly about the transportation options in their region. Multimodal transportation, for instance, is a critical solution for traffic congestion issues. This focuses planning efforts not merely on reducing traffic, but on creating and expanding alternative options for transportation. It emphasizes people over cars by adding measures like more bike lanes, pedestrian corridors, and forms of micromobility such as e-bikes and scooters.

Planners in Northern Virginia found that traffic data pointed them toward precisely this solution to their congestion conundrum. They analyzed the numbers to discover corridors with the highest proportion of short trips. This allowed them to focus on improving bicycle and pedestrian routes, expanding bike-sharing options, and adding more shuttles, eliminating as many as 3.8 million vehicle trips annually.

Public transportation is another facet of multimodal mobility, and it’s a congestion solution in its own right. Investment in public transit involves more than merely adding more buses or increasing the number of light rail trains, however. Creative solutions can involve adding more bus lanes or adjusting bus schedules to better match commute schedules and encourage more ridership.

bus and cyclist in multimodal non-vehicle lane

Fixing Traffic Congestion Problems With a Multi-Pronged Approach

Addressing traffic congestion requires a careful, nuanced approach to the problem. As you can see from just a few examples, the causes of congestion are as diverse as the regions that deal with it. Solutions must be tailored to specific causes to truly be effective.

In most cases, this will require a multi-pronged approach rather than a single solution. Like the planners in Napa, Shreveport, and Northern Virginia, you may find that your city’s busiest corridors require a few adjustments to bring congestion down to more manageable levels. Congestion pricing may not work in your area, but perhaps combining road diets with a multimodal approach will do the trick.

What is Traffic Congestion Analysis?

Transportation planners and engineers often gather data existing roadway conditions to identify congested road segments, diagnose the causes of delays, and determine the best solution to improve traffic flow.

Metrics used to measure congestion and evaluate solutions often include:

Vehicle Hours of Delay – to understand where and when traffic delays occur, and how severe they are
Vehicle Speeds – to understand where and when traffic slows to below free-flow conditions
Vehicle Volumes – to determine whether roadway capacity is sufficient to support actual vehicle activity, and where traffic could potentially be rerouted
Turning Movement Counts – to understand how traffic patterns at intersections impact congestion on the nearby road network

Transportation analysts may combine data from physical traffic counters, manual counts, surveys, and big data platforms to create a comprehensive picture of congestion causes and potential solutions.

Undoing Urban Congestion With Big Data

As with any complex issue, there is no quick fix to traffic congestion. But having big data at your fingertips can put congestion mitigation in the fast lane by avoiding the delays and sample size challenges with traditional data collection methods such as manual counts and surveys.

StreetLight’s Congestion Management Quickview, a feature of StreetLight Insight®, is specifically designed to help planners and engineers quickly access detailed data on congestion trends for their region. It enables easy analysis of important metrics like hourly traffic volume and throughput, and you can use it to compare data across different metro areas.

To learn more about how it works, check out this step-by-step walkthrough. And for more info on big data solutions to traffic congestion, check out our Congestion Solutions page.

congestion management quickview gif — *StreetLight subscribers can use the Congestion Management QuickView (pictured above) to see regional congestion trends and investigate congestion on individual corridors.*

Texas A&M Transportation Institute. “2021 Urban Mobility Report.” https://static.tti.tamu.edu/tti.tamu.edu/documents/mobility-report-2021.pdf
Texas A&M Transportation Institute. “Support for Urban Mobility Analysis.” https://static.tti.tamu.edu/tti.tamu.edu/documents/TTI-2021-2.pdf
Federal Highway Administration. “Traffic Congestion and Reliability: Trends and Advanced Strategies for Congestion Mitigation.”  https://ops.fhwa.dot.gov/congestion_report/executive_summary.htm
PwC. “Mobility insights: Tackling the growing issue of congestion in urban areas.” https://www.pwc.com/us/en/industries/industrial-products/library/mobility-insights-tackling-congestion.html
National Library of Medicine. “Current Understanding of the Effects of Congestion on Traffic Accidents.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6766193/
Texas A&M Transportation Institute. “How to Fix Congestion.” https://policy.tti.tamu.edu/congestion/how-to-fix-congestion/
Texas A&M Transportation Institute. “Variable Pricing.” https://static.tti.tamu.edu/tti.tamu.edu/documents/policy/congestion-mitigation/variable-pricing.pdf

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What Is a Smart City?

What Is a Smart City?

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What Is a Smart City?

Smart City Technologies

See how data can help you fix traffic jams, speeding, and more

How Smart Cities Use Transportation Data

Real-World Examples of Smart City Transportation Projects

Temecula Retimes Traffic Signals

Vancouver Makes the Case for Bus Infrastructure

Richmond Measures Equitable Access to Multimodal Transportation

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How Can a Road Diet Improve Safety for Everyone on the Road?

How Can a Road Diet Improve Safety for Everyone on the Road?

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So, What Is a Road Diet?

Key Safety Considerations

For Vehicles

For Pedestrians

For Cyclists

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How Effective Is a Road Diet?

Finding the Best Approach With Big Data

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Better Budget Planning with Big Data: 4 Ways Transportation Agencies Use Data to Build Budgets, Secure Funds, and Save Money

Better Budget Planning with Big Data: 4 Ways Transportation Agencies Use Data to Build Budgets, Secure Funds, and Save Money

1. Prioritizing Projects for Next Year’s Budget

2. Save Money Over Traditional Collection Methods

3. Secure Grant Funding

4. Use Funds Effectively Before It’s Too Late

What Is a Stroad, and Why Is It Dangerous?

What Is a Stroad, and Why Is It Dangerous?

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What is a stroad?

The problem(s) with stroads

Why are stroads dangerous?

How do stroads impact emissions?

Are stroads bad for the economy?

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How to fix stroads

Can stroads be prevented?

Turning stroads into roads

Turning stroads into streets

Data to improve safety on stroads

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What Is Congestion Pricing, and Is It Always the Right Choice?

What Is Congestion Pricing, and Is It Always the Right Choice?

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The Critical Issue of Traffic Congestion

What Is Congestion Pricing?

Perks and Drawbacks of a Price-Based Approach

Proven Benefits

Congestion Fees Are Effective at Reducing Traffic

Road Pricing Has Health Benefits

It Supports Other Transportation Goals

Criticisms and Limitations

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The Model Is Unfair

Congestion Pricing Is Unconstitutional

Other Options to Consider

Road Diets

Adjusting Traffic Flow

Multimodal Transportation

How to Know if Congestion Pricing Is Right for Your City

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What Is a Vulnerable Road User?

What Is a Vulnerable Road User?

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What Is a Vulnerable Road User?

What Is a Vulnerable Road User Safety Assessment?

How to Make Streets Safer for Vulnerable Road Users

Safe Infrastructure for Pedestrians and Cyclists

Safe Infrastructure for Other Vulnerable Road Users

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Data to Support Vulnerable Road Users

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