What Is a Road Diet? The Data Behind How They Work and How To Implement Them
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.
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.
Photo source: Virginia DOT, reprinted in the U.S. DOT’s Road Diet Informational Guide
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:
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.
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 incentivizes more travelers to choose public transit in NYC.
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.
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.
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
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.
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.
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.
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.
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.”
Take action on unsafe streets with speed data, bike/ped metrics, and more
Explore the resources listed above and don’t hesitate to reach out if you have any questions. We’re committed to fostering a collaborative community of transportation professionals dedicated to building a better future for our cities and communities.
As concerns around productivity, sustainability, efficiency, and social equity have grown across the U.S., so has the importance of mobility. And though transportation infrastructure has been advanced and codified over centuries under the formal governance of federal and state-level Departments of Transportation (DOTs), Metropolitan Planning Organizations (MPOs), local municipalities, and certain commercial bodies, there is still a long way to go to ensure safe, accessible, and equitable mobility for all.
To make progress, it helps to understand the difference between mobility as a holistic term and transportation as a narrower focus. Mobility is a more comprehensive topic, and moves beyond physical transportation into the whole ecosystem. An analysis of mobility issues may show that some Americans have only limited access to transportation modes, thus limiting their mobility. Some legacy transportation modes only work independently of others and contribute to growing sustainability worries.
This article explores why local authorities and enterprise companies must pay close attention to mobility in transportation. It also suggests ways to take advantage of the tremendous wealth of data that’s now available to help with planning and growth.
We’ll focus on the following areas:
Defining Transportation and Mobility
Why Does Mobility Matter?
What’s the Difference between Mobility on Demand and Mobility as a Service?
Smart Transportation and Mobility
The Data Behind Better Mobility
Defining Transportation and Mobility
Transportation refers to how goods and people move from point to point. It includes elements such as infrastructure, vehicles, fuel, regulation, logistics, and technology. For example, planners need to decide if roads, highways, bridges, and public transit systems have sufficient capacity or efficiency.
Mobility looks beyond the “nuts and bolts” of transportation to assess how systems offer good access and ease of movement to people and things. The distinction may seem subtle, but focusing on how much people have the ability to move helps highlight factors of accessibility and equity.
A transportation system might provide the opportunity for people and things to move from place to place in one way or another, but a person may still be immobile within this system due to factors like disability, poverty, racial profiling and discrimination, or an inability to understand the language of roadway signs or public transit instructions.
Mobility systems help make transportation more efficient, minimize congestion, reduce travel times, and ensure a good flow of people within an area. Good mobility systems also offer a variety of transportation options catering to various needs like walking, cycling or public transport, as well as shared mobility services.
What’s an Example of Good Mobility?
When a community has good mobility solutions, its people have access to various transportation services, some of which cater to the individual needs of those on low income, the elderly, or people with disabilities. When new infrastructure or policy is added to the community, efforts are made to ensure it is equitable and inclusive. This in turn means people can use the transportation network to easily access essential services like recreation, education, healthcare, and employment.
Why Does Mobility Matter?
Mobility issues affect the economy, the environment, safety, and social equity in many ways.
Productivity and the Economy
While transportation networks are built to enable to movement of people and goods, mobility focuses on the factors that impact people and things’ ability to move. Therefore, while the movement of goods via freight, aircraft, and ships is one key way transportation systems impact the economy, a focus on mobility will further highlight the human elements of a well-functioning economy.
We’ve already noted that a good mobility system ensures people can access places of employment, the healthcare that keeps them well enough to work, and education systems that can help prepare them for specialized labor and teach financial literacy. In addition, when mobility systems are efficient, commute times are reduced, delivery drivers arrive quickly, and customers have easy access to goods and services.
Studies confirm that when mobility is compromised, retail businesses suffer. For example, when vehicle and pedestrian traffic dropped during the pandemic, retail vacancies also spiked. As people regained some of their mobility and traffic began to recover, so did retail vacancy rates, though the impact of COVID still lingers in many cities.
Social Equity and Quality of Life
Mobility improves the quality of life within communities, giving access to careers, healthcare, education, and recreation. Likewise, mobility supports social inclusion, giving people convenient access to spaces of shared community, governance, care, culture, and more. Public transportation is a key part of creating convenient, accessible access to these facets of social life, yet 45% of Americans have no access to it. [1]
If people do not have equitable access to transportation modes, this inevitably leads to disparity and social injustice. [2] Planners can consider topics like “spatial mismatch,” where there’s a lack of connectivity between employment centers and communities. They may investigate countermeasures such as reverse commuting, to connect low-income city areas to a suburban job center.
Meanwhile, extreme weather events are in the news, and mobility systems need to become far more resilient in the face of climate change. [3] For example, rising sea levels and extreme storms cause flooding and storm surges, which damage roads and bridges. Over time, this can also weaken roadway materials, leading to higher repair bills and traffic congestion.
Excessive heat could also damage rail tracks and cause cracks to appear in roads, posing safety risks for travelers and transportation workers.
As the climate crisis causes more extreme weather events like wildfires, floods, and landslides, the ability to evacuate also becomes all the more critical to saving lives. Access to safe modes of transportation and evacuation routes with enough capacity to support mass travel out of an affected area can become major factors to survival, as well as the ability to return, recover, and rebuild after disaster strikes.
Congestion and Commuting
The economic cost of congestion is significant, especially in large cities. It can lead to wasted time, energy, and fuel as commute times stretch and people take more time on the way to work. To relieve congestion, transportation agencies might add separate bus or bike lanes, or completely redesign a busy intersection to improve flow. For example, they may convert the intersection into a traffic light-controlled operation or install a roundabout.
Get your Guide to the Transportation Data Revolution
Safety and mobility are intrinsically linked. When people do not have access to safe means of travel, their mobility is dramatically reduced. Vice versa, if someone is not mobile, they will likely lack access to resources that keep them safe.
For example, if someone who relies on public transit to get around does not have a safe pedestrian path that can take them from a bus stop to a healthcare facility, they may be forced to miss doctor’s appointments because they cannot travel without putting themself in danger. Simultaneously, this lack of access to medical care also makes them vulnerable to disease, disability, and death.
The danger people face on U.S. roads mustn’t be understated. Although there was a slight decrease in road fatalities across the US in 2022, these deaths represent a rate of 1.35 fatalities per 100 million vehicle miles traveled.4 In addition, pedestrian fatalities actually increased over this period, even as pedestrian activity plummeted.
Although vehicle safety regulations in the U.S. have improved over the years, they still leave much to be desired, and fail to take into account the safety of those outside vehicles such as cyclists, pedestrians, and road workers. Our Transportation Safety Data Handbook has more information on how transportation professionals can assess road safety and move toward safer infrastructure and operations.
What’s the Difference between Mobility on Demand and Mobility as a Service?
While infrastructure and policy are critical to mobility, recent technological developments also hope to advance urban mobility. Two key developments in this area have been the emergence of mobility-on-demand (MoD) and mobility-as-a-service (MaaS) technologies.
MoD provides on-demand access to a range of transportation systems throughout the community. These could include micro-mobility (small, low speed, electrically-powered transportation options) or ride-sharing solutions such as Lyft or Uber.
On the other hand, MaaS has a more integrated and broader focus involving a range of transportation modes. These might also include ride sharing, but extend to public transit and more, providing an end-to-end and seamless transportation experience for a range of users.
For example, apps can be used to deliver real-time information about public transportation, including train and bus schedules as well as info about ride-sharing options so people can plan their journeys.
MoD and MaaS are part of a larger ecosystem of smart transportation technologies that are advancing mobility, which we’ll explore next.
Smart Transportation and Mobility
Smart transportation solutions help to create more sustainable, efficient, and convenient mobility systems. These solutions rely on cutting-edge technology and connected infrastructure. Efficient services depend on the collection and analysis of data from various sources with the aim of optimizing systems and enhancing mobility. These data sources can include road sensors, mobile apps, GPS, traffic lights, connected vehicles, and more.
Because smart transportation systems often use data from personal devices like smartphones and connected vehicles, strong data privacy practices are key to ensuring positive impact. For example, you can learn how StreetLight anonymizes and validates traffic data here.
For example, smart transportation systems can support mobility by:
Delivering relevant and up-to-date data to help travelers make better or more informed decisions. Travelers might reference public transit schedules and real-time vehicle positioning, traffic conditions, or parking availability. This can improve mobility by reducing travel time and congestion as well as boosting transit ridership.
Creating more seamless integrations between different modes of transportation. For example, smart transportation systems might help travelers plan a route that allows them to bike safely to the nearest bus stop, and which stop to get off so that they can use a protected bike lane to travel the remaining distance. This seamlessness encourages people to rely less on private cars and plan point-to-point journeys through these multi-modal solutions.
Providing transportation professionals with the data they need to adjust traffic signals and optimize daily operations based on real traffic patterns, leading to safer travel with less congestion.
Minimizing human mistakes for safer roadways through collision avoidance systems and other in-vehicle smart tech.
The Data Behind Better Mobility
As noted in the section above, advancing mobility effectively relies on having actionable data about how people and vehicles move, whether they are walking, biking, busing or driving — or even using multiple modes in a single trip. Transportation professionals often rely on automatic traffic counters, manual counts, or surveys to collect this data, but these traditional methods each have limitations.
More and more, transportation planners and engineers are supplementing these traditional methods with online, on-demand traffic data platforms, which use big data methods to deliver more information for more roads and more modes, for any time of the day or year.
For example, in the video below, Xinbo Mi, a Senior Transportation Engineer at Evansville MPO explains how the agency uses big data analytics from StreetLight to understand real traveler patterns, such as the top routes people use to access a major regional hospital, and who is actually using existing infrastructure.
Explore the resources listed above and don’t hesitate to reach out if you have any questions. We’re committed to fostering a collaborative community of transportation professionals dedicated to building a better future for our cities and communities.
In the United States, transportation planning goals and existing road design are often out of sync. In many U.S. cities, roads were built first for vehicles, with little thought given to other types of transportation.
This imbalanced approach has far-reaching effects, impacting public health and well-being in many ways. In 2022, there were over 7,600 pedestrian deaths in the U.S., more than 17% of all traffic-related fatalities. [1] Meanwhile, the transportation sector is responsible for more than 25% of all pollution-related deaths each year. [2] Not only that, but the existing road infrastructure in many cities fails to account for the 9% of U.S. households that don’t have a car [3] or the 45% of Americans who lack access to public transportation. [4]
Solving these problems requires a different approach to transportation. Instead of putting the majority of public and private resources into one mode of transportation (i.e., vehicles), cities can expand multimodal options, investing in infrastructure that supports a wide range of transportation modes, from public transit to pedestrian traffic. By shifting to multimodal transportation, we can make our roadways safer and more accessible for all — and move the needle in the fight against climate change.In this post, we’ll cover:
Multimodal transportation definition
Multimodal vs. intermodal transportation
Benefits of multimodal transportation systems
Building complete streets
Understanding multimodal movement through data
What Is Multimodal Transportation?
In one sense, the definition of multimodal transportation is straightforward: It’s an approach to transport that incorporates all modes people use to get around. These may include:
Automobiles
Commuter railways
Buses
Bicycles
Walking
Micromobility modes such as e-bikes and scooters
A fully multimodal transportation system features not only roadways that can support a variety of transport methods, but also a well-integrated public transit system. In other words, the entire mobility infrastructure must be designed to support a variety of ways for people to get around, along with easy commuter access to public transit and ease of transition between modes.
For example, when placed near every bus stop or subway access point, sidewalks and crosswalks can enhance safety and accessibility for cyclists and pedestrians. Public transit can also be designed to allow for easy transportation of bikes, and transit stations equipped with benches and shelter. Many American cities lack these infrastructural features, instead featuring mostly multilane roads without bike lanes, few crosswalks, open-air transit stops, and lots of land dedicated to vehicle parking lots.
Bus riders with skateboards wait at a bus stop, combining multiple modes of transportation in one trip.
Multimodal vs. Intermodal Transportation
A fully multimodal system is also intermodal, meaning that it facilitates a seamless flow of commuters across the various methods of transit. It also prioritizes pedestrians and other non-vehicle commuters in a way our current systems often do not.
For instance, if someone wants to visit the grocery store or the barber, intermodal design makes it possible for that person to safely choose non-vehicle options for getting there, such as walking or biking. If the trip is far, it might also ensure that person can easily bike to the nearest bus stop, bring their bike onto the bus, and then safely disembark and securely park their bike at their destination.
In a city that prioritizes intermodal design, a commuter can easily look up public transit stops and schedules online or on a mobile app. They can even find available e-bikes in the same app and plan their route accordingly. In one fluid process, they can walk to the e-bike, rent it, ride to the bus stop, wait in shelter and safety, and get to their destination on time, regardless of where they live or their socioeconomic status. True multi- and intermodal transportation systems dissolve the boundaries between different modes of travel.
While this vision is far from realized in any American city today, there are encouraging signs of transformation. While denser cities like New York and Chicago are frequently cited, Memphis also offers a promising model for more typical American cities. Memphis city planning agencies have invested heavily in multimodal transportation, such as bike paths, carpool lanes, trolleys and even water taxis. [5] These investments have also positioned Memphis as one of America’s leading cities for freight and logistics operations. [6]
The Benefits of Multimodal Transportation Systems
Transitioning to a multimodal transportation system brings a wide range of advantages, but we can summarize them in terms of their equity, environmental, and economic benefits.
How Multimodal Transport Is More Equitable
Multimodal transportation is more equitable than a single-mode system, both in terms of transportation access and public health.
As noted above, roughly 9% of American households have no access to a vehicle. However, that lack of access is skewed heavily toward minority communities. A full 18% of Black households lack vehicle access, for example, while the same can only be said for 6% of White households. [3] Many minority communities also find it harder to access efficient means of public transportation. In some cities, Black commuters take 25% longer than White commuters to reach their workplace destination. [7]
These inequities extend beyond race and class and also cut across age lines. One AARP study revealed that 48% of Americans over age 50 don’t have a comfortable place to wait for the bus, while 47% can’t access crosswalks to cross main roads safely. [8]
The effects of such inequities are multifaceted, but perhaps none illustrates the disparity more than health outcomes. Pollution from transportation has an outsized impact on low-income communities, minorities, and young children. [9] Meanwhile, access to active forms of transportation like biking and walking has been correlated with increased physical activity, resulting in a 12% decrease in mortality and an 11% drop in cardiovascular disease. [10] Finally, deaths involving vehicles disproportionately affect pedestrians, children, older adults, and Black Americans. [11], [12]
Poor air quality from pollution results in 100,000–200,000 annual deaths in the U.S. [13] However, the transportation sector’s effects on air quality extend beyond immediate public health concerns to threaten the environment as a whole. Currently, transportation accounts for 29% of all greenhouse gas (GHG) emissions in the U.S., more than any other sector. [14]
On a global scale, the United Nations has set a target of a 50% reduction in transportation-related carbon dioxide emissions by 2050, citing this as a critical target to help reach larger goals for mitigating climate change. [15] While many of these initiatives focus on the transition to electric vehicles — and they should — there is also a case to be made for a broader focus on multimodal transportation.
For instance, one study showed that cyclists produced 84% fewer greenhouse gas emissions than those who used cars or public forms of transit. [16] Making cycling, walking, and e-mobility more accessible and safe could have a substantial effect on GHG emissions. Even moving more Americans from cars to public transit would go a long way.
How Multimodal Transport Boosts Economic Prospects
It’s no secret that automobiles are expensive. Depreciation, maintenance, and rising fuel expenses are all costs of ownership, and the purchase price of vehicles has risen steadily in recent years. [17] On top of that, today’s high interest rates make financing a car an even more costly proposition.
One of the simplest solutions to this cost burden is to make cars less of a necessity. When more Americans can choose alternative forms of transportation, they can allocate less of their budget toward getting around. For instance, shifting from vehicle to public transportation would save the average American $13,000 a year, according to the American Public Transportation Association. [18]
However, a multimodal system does more than simply reduce expenses — it also creates an onramp for upward economic mobility. Studies have shown a strong correlation between shorter commute times and economic mobility. [19] Yet, many high-paying jobs or better opportunities remain out of reach for low-income and minority communities, simply because the commute is too long and costly. By expanding access to efficient and affordable public transport, adding more forms of micromobility, and making transit stops easier to reach by bike, multimodal systems can help to bring these jobs within reach.
This impact extends beyond individual citizens to impact the local economy as a whole. Although more research is needed to secure concrete data, numerous studies have shown positive impacts on local business revenues when cities invest in making their roads more pedestrian- and bike-friendly. [20]
Building Complete Streets
Ultimately, to advocate for multimodal transportation is also to advocate for what are known as “Complete Streets.” Although true multimodal logistics and planning must account for more than just street design, no multimodal system is sufficient without considering this critical component.
A Complete Streets approach considers accessibility and safety from every angle when it comes to street layout. From adding bike and bus lanes to upgrading traffic signals for the visually impaired, Complete Streets policies aim to make roadways safe and user-friendly for everyone.
Designing Complete Streets has been shown to slow down traffic even without substantially increasing congestion. For instance, one StreetLight study of a bike lane installation in North Kansas City, Missouri, showed that the bike lanes nearly eliminated traffic traveling over 40 miles an hour while only increasing the average vehicle trip by five seconds.
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.
Understanding Multimodal Movement Through Data
Effectively implementing a multimodal transportation plan always begins with understanding the current traffic patterns and modes of transportation in your area — and data access is essential for that understanding. What percentage of people use vehicles as opposed to public transit, cycling and walking? How many of the cars on the road are electric? Where is public transit readily accessible? Data offers answers to these important questions.
For example, when a Vancouver transit agency, TransLink, needed to gain political buy-in for investments in multimodal infrastructure, they combined StreetLight’s vehicle volumes data with their own ridership counts to show that bus usage was much higher than previously understood, helping them make the case for new bus lanes and rapid bus lines.
Transportation data can also help evaluate existing multimodal infrastructure for equitable impact. For instance, in the video below, Alex Bell of Renaissance Planning explains how they used StreetLight’s multimodal metrics to help Richmond, VA develop measures of accessibility for walking, biking, and transit modes. This data allowed them to reveal the causes and impacts of low access, including who is most underserved by existing infrastructure.
Governors Highway Safety Association. “Pedestrian Traffic Fatalities by State.”
Environmental Science and Technology Letters. “Reducing Mortality from Air Pollution in the United States by Targeting Specific Emission Sources.”
National Equity Atlas. “Car access: Everyone needs reliable transportation access and in most American communities that means a car.”
American Public Transportation Association. “Public Transportation Facts.”
Explore the resources listed above and don’t hesitate to reach out if you have any questions. We’re committed to fostering a collaborative community of transportation professionals dedicated to building a better future for our cities and communities.
In the United States, a transportation safety crisis is leading to record numbers of fatalities: 38,680 people were killed in motor vehicle crashes in 2020, and by the end of 2021, nearly 43,000 more people had died on U.S. roads, marking a 10.5% overall increase in deaths — and the highest death toll recorded since 2005.
Among these fatalities, about 13% were pedestrians — that’s 7,388 people who died while walking, the highest number recorded in decades.
At the same time, the rate of fatalities per 100 million vehicle miles traveled (VMT) has also worsened, increasing significantly in 2020, likely due to high rates of speeding during early COVID lockdowns that led to empty streets. But this increase held steady in 2021.1
Faced with these fatal statistics, the need for safer roadway infrastructure is clear. To address the problem, transportation professionals must diagnose the factors that make roads so fatal and implement countermeasures that are proven to work. But not every road needs the same safety improvements. So how do you ensure safe transportation infrastructure?
In this post, we’ll examine:
What makes public roads safer for various modes of travel
The Safe System Approach to transportation safety
Ways to improve transportation infrastructure safety
The data behind safer infrastructure
What Makes Roads Safe for Each Mode of Travel?
There is no single factor that makes all roads safer or more equitable. Each road and mode of travel may benefit from different types of infrastructure and policy, making a data-informed approach key to effective safety interventions.
It should be acknowledged that non-infrastructural factors — such as vehicle design and driver education — also impact road safety and should be considered as part of a holistic approach to reducing fatalities and injuries on the road.
However, in this article, we’ll focus specifically on transportation infrastructure and road design strategies that boost transportation safety. Below, we’ll explore some of the ways you can make public roads safer for various modes of travel.
Public Transport Safety
Public transport safety has to address a couple of overarching concerns: First, modes of public transportation, like city buses or streetcars, need safe roadways. Second, access points like bus stops must give riders safe ways to wait, embark, and disembark.
Riders wait at a bus stop with ample seating, good lighting, and textured curb edges that improve accessibility for those with visual impairments.
Road Safety Infrastructure for Public Transport
Bus lanes are one excellent option for improving the safety of public transport. Not only do they improve travel times, but they also give buses a safe lane for stopping without interrupting car traffic. In a 2019 study by the Maryland Department of Transportation, bus lanes reduced bus-involved crashes by 12%.2
Raised medians can also help keep transit users safe from oncoming traffic as they get on and off a public transport vehicle.
Railway crossings are also an essential tool in making roads safer for public rail.
Safer Spaces for Public Transport Users
To make public transit access points safer for riders, these tactics can be helpful:
Placing bus stops consistently along routes to make them easier to find.
Placing useful crosswalks near transit stops to prevent unsafe crossings.
Using apps, mobile webpages, and other methods to reduce wait times and make schedules, route maps, and other important information accessible.3
Ensuring that bus stops, stations, and other transit hubs are well lit.
Ensuring transit hubs are accessible to people with disabilities, providing ample seating and spaces for wheelchairs, strollers, baby seats, groceries, and so on.
Establishing more frequent service to ensure that people don’t have to wait alone at stations or stops.4
Cyclist Safety
Cycling activity boomed during the pandemic, increasing 37% across the U.S. between 2019 and 2022. But many roads are still unsafe for cyclists and in need of safety interventions to ensure increased biking doesn’t result in increased road deaths for these cyclists.
For example, early in the pandemic, Walk Bike Nashville (WBN) heard resident concerns about increased rates of speeding. They analyzed traffic volume and speed, and discovered that motorists took advantage of empty streets to drive much faster. In June 2022, 22% of drivers were traveling 30 mph over the speed limit on one key roadway.
Additionally, while bike lanes can improve safety for cyclists by increasing their visibility and giving them dedicated space on the roadway, not all bike lanes are created equal. While an unprotected bike lane is usually better than no bike lane at all, some bike lanes can still leave cyclists in the path of opening car doors, swerving vehicles, or improperly parked cars that block the bike lane entirely.
Bike lanes that are protected from vehicle traffic or dooring by central hatching, raised medians, various types of barriers, or even street art can keep cyclists much safer than unprotected bike lanes.
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.
Pedestrian Safety
Unlike bicycling, walking activity has plummeted since the pandemic. An analysis of pedestrian activity in the top 100 U.S. metros and 48 states (excluding Hawaii and Alaska) between 2019 and 2022 revealed declines in every region, ranging from 23 to 49 percent.
Even with these declines, pedestrian road deaths reached a 40-year high in 2022, according to the Governors Highway Safety Association.5
As noted above, safe vehicular speeds are a crucial component of pedestrian and cyclist safety. Speed reduction tactics like road diets (see section below), widening sidewalks, narrowing lanes, and reducing speed limits can have huge positive impacts on pedestrian safety.
Increasing the visibility of pedestrians, especially at intersections, can also dramatically impact pedestrian safety. Tactics like daylighting — where the sides of the road near an intersection are kept free of parked cars and other visual obstructions — ensure drivers can see pedestrians and vice versa, reducing the risk of pedestrians being hit as they cross the street.
Reducing crossing distance also helps keep pedestrians safe by reducing the amount of time spent crossing vehicle lanes. Pedestrian refuges and bulb-outs are common ways to accomplish this goal. Signalized crosswalks and synchronized signal timing are also key to intersection safety for pedestrians.
Vehicle Safety
Many of the tactics explored above also promote vehicle safety. Slower speeds, attentive driving, and smooth traffic flow help keep drivers out of accidents. Reduced speed limits, clear signage, daylighting, and optimized traffic signals are just a few of the tactics discussed above that can also improve these safety factors.
Some additional tactics like rumble strips, median barriers, and roadside design improvements at curves specifically target improved road safety for vehicles.
Rumble strips are milled or raised pavement elements placed along the edge of a travel lane that cause vibration when driven over, alerting drivers when they are veering outside the travel lane.
Median barriers help separate opposing directions of traffic along a roadway, and help avoid head-on collisions on two-way roads.
Horizontal curves account for 27% of all fatal crashes, according to the FHWA.6 Improved signage, clear zones, slope flattening, shoulder widening, and various types of barriers and guardrails can all help improve these dangerous roadway segments. Clear zones and wide shoulders give drivers a safe place to regain control of their vehicle, while barriers and guardrails help keep them from veering off the roadway or into oncoming traffic.
What Is the Safe System Approach to Transportation Safety?
The Safe System Approach is a holistic strategy aimed at reducing road deaths to zero. This approach was originally inspired by the Vision Zero movement, which began in Sweden and has since gained traction across the globe.7
The goal of the Safe System Approach is to make the entire transportation system safer — from roadway infrastructure to vehicle design, driver education, and emergency response — so that no one is killed or injured while using roadways. It recognizes that people make mistakes and vehicles malfunction. Thus, roadways need to be designed in a way that accommodates human and mechanical errors to help prevent crashes, injuries, and fatalities.8
Part of what makes the Safe System Approach effective is that it focuses on making proactive safety improvements. For example, city planners may discover an area that experiences recurring safety issues, and set out to fix those issues. Under a Safe System Approach that relies on proactive safety planning, officials would also be able to flag sites that share the same design as the one experiencing safety challenges. They can then flag these similar areas, making improvements to prevent safety issues before problems arise.9
StreetLight’s Safety Prioritize tool helps planners and operations managers diagnose safety concerns and identify the best countermeasures based on the most up-to-date mobility data.
Top Ways to Improve Transport Infrastructure Safety for All
Beyond the safety interventions explored above for each mode of travel, there are a few common safety tactics that can benefit all road users. In step with a Safe Systems Approach to road safety, these tactics often achieve holistic changes to how roadways are traversed, rather than addressing safety concerns piecemeal.
Building Complete Streets
The “Complete Streets” approach builds on Safe Systems by focusing on roadway infrastructure that equitably addresses the needs of all road users — not just vehicles. This includes bikers, drivers, public transit users, pedestrians, and even roadside diners.
Just as importantly, the Complete Streets approach also takes into account all ages and abilities. That means designing features for potentially disadvantaged groups like the elderly, people who use wheelchairs or walking aids, or people with hearing and vision impairments.
Thus, most Complete Streets policies include provisions to add bike and bus lanes to roadways so that municipalities can improve safety and access for these modes. For pedestrians, Complete Streets improvements may include curb extensions, audio traffic signals for the vision impaired, safer crosswalk designs, or daylighting.
Road Diets
Road diets are a proven safety solution that can often be implemented at very low cost. In many instances, the only expense is the cost of restriping a roadway.
Roads on a road diet take one or more lanes of general vehicle traffic and transform them into something else: bike or pedestrian lanes, bus lanes, or even central turn lanes that can be used by vehicles traveling in both directions. In some cases, municipalities may also use the space from removed vehicle lanes to install or widen existing medians, sidewalks, or shoulders.
Road diets often work to lower vehicle speeds for improved cyclist and pedestrian safety, or even to promote public transportation options like busing. This often comes with added advantages, like reducing greenhouse gas emissions while creating more walkable spaces—or spaces that are more accessible to underserved populations who rely on public transit.
Temporary road diets can also be created using jersey barriers, traffic cones, or portable pylons — a tactic many cities used during the COVID pandemic to calm traffic. In Waterloo, Ontario, for example, authorities put up black-and-orange construction barrels along 30 kilometers of roadway to convert space previously devoted to vehicles into temporary bike lanes. A study by StreetLight confirmed that the new bike lanes increased bike activity by 39% while reducing vehicle speeds by 12%.
Although proposed road diets often raise concerns that reducing lanes could lead to increased congestion and longer travel times, studies often show that travel times do not significantly increase after the implementation of a road diet.
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.
A painted crosswalk along with temporary pylons and traffic cones help calm traffic and protect cyclists on Armour Road in North Kansas City, Missouri.
The Data Behind Safer Transportation Infrastructure
As we’ve explored, there are many ways to promote safer transportation infrastructure — and identifying the best safety interventions for a given intersection, roadway, or community requires a deep understanding of existing conditions and the potential impact of various approaches.
Transportation data like vehicle volumes, bike and pedestrian activity, turning movement counts, vehicle speeds, and more can help transportation professionals choose the right countermeasures, anticipate their impact, and measure before-and-after success.
Planners and engineers often rely on data from permanent traffic counters, manual counts, or surveys to understand existing conditions and anticipate impact — but not all roads have counters installed, and manual counts and surveys can suffer from sample size issues and bias.
Online transportation data analytics can help fill data gaps and avoid putting staff in harm’s way to collect reliable information on how people and vehicles move. The video below shows how DOTs, MPOs, and other agencies can leverage online analytics to perform safety studies and choose the right countermeasures for their region.
For a deeper dive into key safety metrics and how to use them to diagnose dangerous roadways, choose countermeasures, secure funding, and measure success, download our Practitioner’s Guide to Transportation Safety.
1. U.S. Department of Transportation, “The Roadway Safety Problem.” Feburary 2023
2. Maryland Department of Transportation. “Dedicated Bus Lanes Before and After Study.” February 2019
3. Rural Health Information Hub. “Models that Increase Access to Public Transportation.”
4. New York University Rudin Center for Transportation. “The Pink Tax on Mobility: Opportunities for Innovation.” February 2022
6. U.S. Department of Transportation Federal Highway Administration. “Roadside Design Improvements at Curves.”
7. U.S. Department of Transportation Federal Highway Administration. “Zero Deaths and Safe System.” August 2023
8. U.S. Department of Transportation Federal Highway Administration. “NHTSA’s Safe System Approach: Educating and Protecting All Road Users.” Winter 2022
9. U.S. Department of Transportation Federal Highway Administration. “The Safe System Approach: How States and Cities Are Saving Lives.” Winter 2022
Balancing Road Safety and Congestion in Oakland: Big Data Analysis Reveals Potential Solutions for a Dangerous Corridor
Balancing Road Safety and Congestion in Oakland: Big Data Analysis Reveals Potential Solutions for a Dangerous Corridor
Part of Oakland’s High Injury Network, Grand Avenue was slated for a safety overhaul, but a 2023 plan for the roadway prioritizes vehicular throughput over traffic calming measures. Big data analyses can help planners and advocates maintain traffic flow and make streets safer for walking and biking.
In 2021, traffic fatalities in the U.S. reached a 16-year high with nearly 43,000 people killed, a 10.5% increase from 2020. In my hometown of Oakland, the Department of Transportation Director called traffic fatalities an ‘epidemic’, citing 35 deaths in 2022 — the highest number of fatalities in the last 10 years.
To address this, Oakland, like many state and local governments across the country, set in motion an effort to reduce these tragedies in their 2023 Strategic Plan, citing the following safety strategies:
Adopt a Vision Zero policy and pledge to eliminate traffic injuries and deaths
Inform safe designs and infrastructure decisions with data and analysis
Incorporate safety and Complete Streets policies into road design processes
OakDOT’s Multimodal High Injury Network map highlights Grand Ave. among Oakland’s 6% of street miles that account for 63% of severe and fatal crashes.
Grand Avenue is among Oakland’s most treasured corridors. It serves as a major connector between Downtown and residential neighborhoods, hosts major commercial businesses and destinations, and border’s Lake Merritt, Oakland’s most prominent recreational park. But it’s also on Oakland’s High Injury Network, a group of roadways that represent only 6% of street miles but account for 63% of severe and fatal crashes.[1] As a traffic safety advocate and lifetime resident in the East Bay, I was excited to learn a plan was underway to redesign Grand Avenue with safety in mind.
But in June 2023, a new plan for Grand Avenue was published — one that prioritizes vehicle throughput at the potential expense of non-vehicle road users like cyclists and pedestrians.[2] Confused by this new direction, I wanted to use my experience as a Product Manager of Data & Metrics at StreetLight to see if the data could support safety improvements that would still assuage concerns over congestion on Grand Avenue.
Below, I’ll share what my analyses uncovered, and explore how DOTs can use multimodal data to navigate the difficult job of aligning stakeholders and negotiating competing priorities. But to contextualize these findings, it’s important to first dive a little deeper on the history of Grand Avenue.
2018 Grand Avenue Mobility Plan Prioritizes Safety and Traffic Flow
In 2018, Oakland’s Department of Transportation (OakDOT) published the Grand Avenue Mobility Plan, a comprehensive study that used a collection of data sources — including community engagement surveys and StreetLight’s Trip Speed, Roadway Volumes, and Origin-Destination Metrics — to take stock of the mobility, economic, and demographic conditions along Grand and present various redesign options.
The report states that the top two local goals are to “Serve existing residents’ transportation needs, and to improve the safety and comfort of those walking and biking along and across the corridor.” Taken together, these two goals speak to a nuanced and challenging balancing act that urban transportation professionals are constantly navigating: Should a corridor’s design prioritize the movement of vehicles or the safety and comfort of those not in vehicles?
These two goals can often seem at odds, but they don’t have to be.
While infrastructure and operations that benefit walkers and bikers — like bike lanes and reduced speed limits — can raise concerns over congestion and traffic delays, a deeper understanding of existing conditions can often reveal road design options that benefit both drivers and those outside vehicles.
But planners and engineers need robust, multimodal data to weigh all the options.
Existing Conditions on Grand Avenue: Broadway to Grand Lake Theatre
Of the corridor’s four sections, the stretch that connects Uptown to the Grand Lake Theater, which defines the northern border of the lake and park, is the first that will undergo a redesign. This section serves restaurants, businesses, visitors to the park, and the residents of the Adams Point neighborhood. It also connects downtown Oakland to the Hills neighborhoods and highway 580.
As of June 2023, the plan is at the 35% stage, and construction could begin as soon as 2024. [3]
A cross-section of Grand Avenue shows existing infrastructure on the corridor segment between Harrison and MacArthur. Image Source: OakDOT’s Grand Avenue Mobility Plan.
Existing conditions along the corridor feature two multi-use travel lanes, a center turn lane, as well as unprotected bike lanes and parking on each side. There are signalized crossings, but they are spaced far away and do not feature pedestrian islands at the median. Meanwhile, there are also very few curb bulb-outs, which function to improve safety by reducing crossing distance.
Importantly, the existing two travel lanes allow cars to travel quickly and unpredictably, making conditions unsafe for bicyclists and pedestrians. In San Francisco, a 2023 study from SFMTA showed that while 4+ lane roads were only 14% of the network, they constitute 53% of the collisions with bicyclists.[4]
The 2018 Grand Avenue Mobility Plan proposes multiple redesign alternatives, most of which include traffic calming measures that would reduce the number of vehicle lanes and repurpose roadway space for non-car travel such as bus and bike lanes or protected pedestrian medians. This type of roadway treatment is commonly referred to as a road diet — a traffic calming tactic that is proven to improve road safety, though it often prompts concerns over traffic congestion.
Corridor cross sections show four alternatives for a Grand Avenue redesign, which could include lane restriping and roadway construction to make room for medians, protected bike lanes, or dedicated bus and bike lanes.
Given the documented dangers of 4-lane roads and scarcity of existing infrastructure on Grand protecting pedestrians and cyclists, it makes sense that in the 2018 Plan, the most popular option was the Bicycle/Micromobility focus.
However, while earlier design stages maintained this emphasis on calming traffic and improving bike and pedestrian safety, the 35% designs published June 2023 focused on Vehicular Throughput instead.
There are many competing pressures that may have caused this reversal, but the most likely driver of a decision like this is the concern that vehicle volumes are too high for a single lane, resulting in poor Level of Service and congested traffic.
When considering changes to the road design, each corridor needs to be analyzed carefully to balance the needs of motorists, pedestrians, bicycles, transit, and other roadway users. This is where having access to better data can help practitioners pinpoint problem areas and determine how to create a design that avoids gridlock, but also promotes safety.
See which U.S. regions are recovering from a nationwide decline in walking
Analyzing Grand Avenue’s Current Traffic Conditions With Big Data
Generally, the safety on an urban collector like Grand boils down to pedestrian exposure to vehicles moving at high speeds. In the following analysis, I use StreetLight to examine conditions on Grand with the purpose of illustrating whether a road diet treatment — including reducing the lanes and speeds of vehicles — is appropriate, and how it would impact both pedestrian safety and congestion.
To do so, we must answer these fundamental questions:
Where is pedestrian activity highest?
Are vehicle speeds unsafe and where are vehicle speeds highest?
Do vehicular volumes warrant having two lanes in each direction?
Pedestrian Exposure on Grand
My first step was to identify where the most pedestrians are exposed to high-speed vehicles. To do this, I analyzed pedestrian activity at each intersection and overlayed vehicle speeding patterns. Measuring relative pedestrian activity can help transportation planners know where safety-focused interventions can have the highest impact.
A StreetLight InSight® analysis shows pedestrian traffic volumes on the Adams Point segment of Grand Ave.
In the map above, you can see that the highest pedestrian activity closely aligns with the section of Grand that borders the park. The other outlier is on the east corner of the lake, which is the intersection with the largest distance between crossing features such as curb extensions, center medians, or crosswalks (shown below).
Figure 17 of OakDOT’s Grand Avenue Mobility Plan shows existing infrastructure along the Adams Point segment, including pedestrian safety features like crosswalks and curb extensions.
The second step is to analyze vehicle speeds on the corridor, to determine where and when vehicle speeds are dangerous. StreetLight can be used to analyze the 85th and 95th percentile speeds, the standard method for measuring speeding vehicles.
For this analysis, I’ve zeroed in on weekdays from 8-9am, when families are walking to school and people are commuting, as well as weekend days from 12-1 pm, when people are visiting the park.
A StreetLight InSight® analysis shows average travel speeds along the Adams Point segment of Grand Ave. Higher speeds appear in red.StreetLight data visualized in QGIS shows where pedestrians face the most danger from speeding vehicles along Grand Ave.
Looking at the 95th percentile, the data shows that vehicles are often speeding in excess of 10 MPH above the speed limit during critical hours. Importantly, by overlaying the speed and pedestrian activity, it’s clear that the same areas with the most pedestrian activity also exhibit dangerous speeds.
Exposure analysis like this reveals precisely where the highest value interventions could be made. Pedestrian median islands, bulb outs, and high-visibility crosswalks are among the tools planners use to improve safety with or without reducing lanes.
Beyond these pedestrian safety features, the most effective way to reduce fatalities is to reduce speed, which is where concerns about congestion often surface. That’s because vehicle speeds and roadway capacity are interconnected — a phenomenon that was highlighted during the COVID pandemic, when a drop in vehicle volumes increased the rate of speeding.
To put it simply, when there is excess capacity, drivers will tend to use the extra space to move more quickly. Conversely, when there is less room for vehicles, drivers will tend to slow down.
This is where a deeper dive into vehicle travel patterns on Grand Avenue and adjacent roadways can help evaluate the corridor for lane reduction.
Vehicle Capacity on Grand
When considering how many lanes a corridor should have, traffic engineers will typically look at each direction separately and use the maximum hourly volume to determine the appropriate treatment that avoids congestion. The Federal Highway Administration Road Diet Informational Guide suggests that urban arterial lanes can likely support 750 Vehicles Per Hour (VPH), and possibly up to 875 VPH, but it depends on signal spacing, presence of turning lanes, and other factors.[5]
A StreetLight InSight® analysis shows vehicle volumes along the Adams Point segment of Grand Ave. Higher volumes appear in red.
To study optimal road capacity, first we need to look at how volumes change across the corridor. The image above shows that the corridor can reasonably be divided into two segments with distinct volumes, one along the lakefront, and one from the lake towards downtown. The hourly trends (seen at the bottom of the image) show that traffic peaks on weekdays between 5 and 6 p.m.
Next, the chart below shows how hourly volumes fluctuate during the weekday and weekend day, for each direction.
Data from StreetLight shows hourly directional traffic volumes fall below maximum suggested volumes for a single lane corridor, except during peak weekday evening hours.
The data shows that while most of the day falls below 875 VPH, weekday evening commute hours reach above the threshold recommended for 1-lane corridors. Therefore, according to traditional approaches to capacity planning, with no other changes to expected driving behavior, reducing the travel to one lane would likely cause congestion during those hours.
However, what the capacity benchmark fails to take into account is how traffic would organically reroute to underutilized roadways. Here, Streetlight can be used to understand through traffic behavior, as well as understand nearby capacity and whether it’s likely to help offset capacity changes on Grand.
Data from StreetLight reveals that 25% of Grand Avenue traffic, on average, is cut-through traffic bound for Highway 580.
The charts above show where people on Grand are coming from and headed to. On average, around 25% of vehicles are using Grand to get to Highway 580. During the peak hour, when congestion would occur, that number jumps to 30%. Furthermore, looking at where traffic is coming from, it’s noteworthy that 20% of peak hour traffic on Grand originates as far west as Martin Luther King Jr. Blvd.
During peak hours, 20% of Grand Avenue traffic originates from Martin Luther King Jr. Blvd., according to a StreetLight analysis.
While current conditions indicate that reducing the number of lanes risks congestion during peak hours, there is also evidence that much of this traffic is headed to the freeway and would end up naturally re-routing away from Grand Avenue. Further analysis should be done on the roadways where this traffic is expected to be diverted to determine if they have the capacity to take on the additional traffic.It should be noted that beyond keeping the current number of lanes, there are other ways to manage congestion, like retiming traffic signals or implementing a parking-convertible traffic lane during the heavily trafficked evening commute hour. Finally, and importantly, congestion can be reduced by promoting modeshift to transit and active transportation.
Based on my analysis, there is reason to suspect that a road diet on Grand Ave. could still be a viable solution to safety concerns along this high-injury roadway, and may merit particular consideration on the areas of the roadway where high pedestrian activity and high speeds dangerously coincide.
Although traffic flow and pedestrian safety on Grand may appear to be in conflict, access to robust mobility data for this and adjacent corridors helps reveal road design alternatives that accommodate both.
Vehicle metrics shown here were collected from January to April 2023. Pedestrian activity was collected from November-April 2022.
Explore the resources listed above and don’t hesitate to reach out if you have any questions. We’re committed to fostering a collaborative community of transportation professionals dedicated to building a better future for our cities and communities.
CDC Study Validates StreetLight’s Active Transportation Metrics Against Survey Data
CDC Study Validates StreetLight's Active Transportation Metrics Against Survey Data
StreetLight’s bicycle and pedestrian data offer reliable insights into active commuting behavior, a study by researchers at the Centers for Disease Control and Prevention (CDC) finds.
Physically-active modes of transportation like walking and cycling can make communities healthier and happier. That’s why public health organizations like the CDC are looking for reliable ways to monitor active transportation behavior across the U.S.
Traditionally, collecting data on active transportation behavior has relied on surveys, which presents researchers with limitations. As researchers at the CDC put it,
[Survey data] is often limited to a certain metric or subpopulation (e.g., walking to school among adolescents).1 Moreover, these systems suffer from survey-related biases, coarse geographic resolution, and the intrinsic time lag between data collection and availability.2
So, CDC analysts wanted to determine if StreetLight’s bicycle and pedestrian metrics could provide reliable public health insights instead of relying on survey data alone.
What they found was that StreetLight’s pedestrian and cycling data was particularly useful in measuring active transportation activity in densely populated urban areas, showing strong correlations with findings from the American Community Survey administered by the U.S. Census Bureau.
Even for rural areas, StreetLight’s data also showed moderate to strong correlations for both walking and cycling, providing timely insights for researchers hoping to measure public health factors without the delays and limitations that accompany other data collection methods.
This makes StreetLight’s active transportation data the only bike and pedestrian dataset to be vetted by the CDC. StreetLight’s bike and pedestrian data has also been repeatedly validated and used by agencies across the U.S. since 2019, including MnDOT, the City of Pittsburgh, and VDOT.
According to the CDC study, StreetLight’s historical bike and pedestrian data:
[Offers] public health and transportation professionals an additional tool for assessing walking and bicycling behavior. For example, [it] may be preferable to traditional surveillance data for conducting a time-sensitive project, such as changes in walking patterns during an epidemic, or for assessing the impact of a community design intervention to promote bicycling within a city or town.
1. Fulton et al., 2016; Omura et al., 2021 2. Sallis and Pate, 2021; Whitfield et al., 2015
What Are Complete Streets and How Can Analytics Help Us Build Them?
What Are Complete Streets and How Can Analytics Help Us Build Them?
Focusing on car-centric infrastructure can compromise roadway safety, increase emissions, and leave many without a reliable way to get from A to B. But Complete Streets policies promote safe and equitable outcomes for all road users.
We have a tendency, particularly in the U.S., to design roads for cars and trucks. Decades of vehicle-centric city planning have exacerbated this tendency, as sprawling metropolises make travel by car essential for most Americans.
This focus on car-based travel leaves many people behind. Pedestrians and cyclists face unsafe roadways without bike lanes, sidewalks, or crossings. Those who cannot drive or afford a car struggle to get to work via transit or access essential resources like grocery stores and doctors. People living near congested highways — predominantly communities of color [1] — suffer the effects of both noise and air pollution, impacting health outcomes.
In the face of these realities, we need a paradigm shift in how we design streets. Instead of vehicle-first transportation systems, we need people-first transportation systems. And this new paradigm is already gaining ground through programs like Complete Streets.
What are Complete Streets?
“Complete Streets” is an approach to roadway policy and design that focuses on enabling safe mobility for all road users — drivers, pedestrians, bikers, and public transit riders alike, across the full spectrum of ages and abilities. [2]
For example, a Complete Streets policy may call for the implementation of pedestrian traffic signals that are accessible to those with visual impairments. Policies may also call for added bike lanes and bus lanes to improve safety and access to these transportation modes, or the implementation of curb extensions, crosswalks, and daylighting to provide safer paths for pedestrians.
Many public officials at the local, regional, state, and federal levels are working to build better bicycle, pedestrian, and transit infrastructure through Complete Streets policies. The concept of Complete Streets is now mainstream in transportation, with planners striving to design and build streets that safely accommodate all transportation modes and users. In fact, according to the National Complete Streets Coalition, over 1,700 Complete Streets policies have been passed in the U.S., including those adopted by 37 states, Puerto Rico, and Washington D.C.
In this article, we’ll discuss several benefits to Complete Streets and how we can leverage transportation analytics to build more of them.
Why are Complete Streets more equitable?
Streets with multimode infrastructure offer more ways to travel, increasing mobility for everyone. Whether they drive, bike, walk, or use public transit, Complete Streets give them ways to get from point A to point B. This is especially crucial when point B is an essential resource like food, healthcare, work, or school.
Vulnerable populations, including people of color, people with disabilities, and those who are impoverished or experiencing homelessness are less likely to own or drive a car. Ensuring that non-car travel options exist increases access to mobility for these groups while also benefiting other travelers.
It’s important to note that the existence of non-car travel options doesn’t always ensure the accessibility of these options. Here, we mean accessibility in multiple senses — accessible for people with disabilities and accessible more broadly for all road users. Even when non-car mode options exist, there can be barriers to their use such as inadequate seating at bus stops or English-only signage.
In the video below, Alex Bell of Renaissance Planning explains how he used multimode analytics from StreetLight to compare mode availability to mode utilization in order to diagnose barriers to access for vulnerable populations.
Access to non-car transportation options can also help ensure fewer people suffer from homelessness. According to Jacob Wasserman, a researcher at UCLA who conducted a meta-analysis on transportation and homelessness,
“Homelessness is first and foremost a housing problem, but transportation is so intimately tied into housing. People can only live in places they can afford, which is sometimes really far from [the things they need to reach] because of our transportation decisions.” [3]
And because Complete Streets allow more opportunities for non-car travel, they also reduce overall Vehicle Miles Traveled (VMT), leading to improved air quality and less noise pollution for people living near highways, a group made up disproportionately of communities of color. That brings us to the next question….
Why are Complete Streets more climate-friendly?
Transportation is the top source of greenhouse gas (GHG) emissions in the U.S., at 27% in 2020, according to the EPA. That means the transportation industry has a critical role to play in addressing climate change.
Because Complete Streets reduce our reliance on single-occupancy vehicle (SOV) trips by making it easier to use shared mobility and active transportation options, they also lower total Vehicle Miles Traveled (VMT). By reducing the number of cars on the road, Complete Streets also help reduce traffic congestion, which means less time stuck in traffic with the engine running. With fewer miles traveled and less time spent in cars, emissions drop and air quality improves.
Adding Complete Streets infrastructure to existing roads can also have the effect of calming traffic. For example, road diets — which reduce the number of vehicle lanes and often repurpose the space for multimodal infrastructure — tend to reduce vehicle travel speeds and vehicle throughput without causing the congestion that would lead to increased emissions. Since vehicles are less fuel efficient and emit more CO2 per mile traveled at higher speeds, this means multimodal Complete Streets infrastructure can sometimes double as traffic calming measures that reduce emissions while also improving safety.
In the example below, AEC firm ATCS identified opportunities to invest in multimodal infrastructure on Route 234 Business in Prince William County, Virginia with the goals of reducing congestion, increasing safety, and making travel more sustainable.
Creating these opportunities for mode shift is crucial to decarbonizing our transportation networks, although they are just one strategy we can use to reduce overall emissions. We explore additional strategies in our free guidebook, Measure & Mitigate: Transportation Climate Data Solutions.
Why are Complete Streets safer?
As roads emptied and travel speeds increased during COVID, severe crashes spiked. This made many cities less safe for bikers and pedestrians in particular, highlighting the urgency of infrastructure improvements and traffic calming measures to make streets safer.
Smart Growth America’s map of most deadly vs. least deadly metro areas for pedestrians.
When streets lack multimodal infrastructure like signalized crossings and bike lanes, that doesn’t prevent non-car road users from needing to travel. Many still need to walk, bike, or use public transportation in order to access basic necessities, forcing them to brave streets that lack the infrastructure needed to keep them safe as they travel.
Adding accessible sidewalks, crossings, bike lanes, bus lanes, signage, and other Complete Streets infrastructure helps ensure that not only can people travel, but they can do so safely.
Complete Streets improvements may also mean making streets safer not just for travelers, but also for road workers, outdoor patio diners, and homeless people sheltering under overpasses or asking for help at intersections. In the example below, the City of Pasadena implemented various traffic signal timing techniques to reduce the speed on corridors with outdoor dining, as well as other arterials.
For more strategies to make streets safer, download our free Safety Handbook.
How can we build more Complete Streets?
With all these benefits to Complete Streets, how can transportation professionals make headway on ensuring more of our streets serve all road users?
Implementing official Complete Streets policies can provide the incentive and accountability to get started. In the U.S., the Federal Highway Administration (FHWA) offers guidance for transportation agencies looking to establish Complete Streets policies. [4]
The Federal Transit Administration has also waived the local funding match requirement for Complete Streets planning activities to receive funding through the federal State Planning and Research Program (SPRP) and Metropolitan Planning Program (MPP) through the end of 2026.
Because so many factors might go into making streets “complete,” — bike lanes, bus stops, signage, sidewalks, well-timed traffic signals, and so much more — understanding existing roadway conditions, mode usage, traveler demographics, and the impact of past projects are key. This is where digital transportation analytics come in to help agencies identify high-priority improvements and develop data-supported implementation plans.
StreetLight InSight® allows users to compare bike activity to trip speed info to pinpoint where bikers may face dangerous road conditions.
Transportation analytics for Complete Streets
The right data is necessary to identify and prioritize high-impact roadway improvements, secure project funding, and earn public and political buy-in for your proposed solutions. While traditional data collection methods like sensors and surveys offer helpful data points to support these goals, they often present limitations in scope and sample size. Digital, on-demand transportation analytics fill in the gaps to enrich our understanding of travel patterns and the needs of road users.
Because installing new multimodal infrastructure can be costly and time-consuming, one of the easiest ways to make streets more complete is to evaluate the performance of existing infrastructure and identify opportunities for optimization.
Say you wanted to optimize bus schedules or add stops to an existing route to adapt to shifting travel demand. An Origin-Destination (O-D) analysis using digital traffic data can illuminate where lots of people are traveling between work and home, while the ability to view traffic volumes by time of day can help determine when most people need to travel. Aggregated demographic data can also be overlaid onto travel patterns to understand where vulnerable populations would most benefit from added stops.
For example, when commuting patterns shifted after COVID, bus ridership in San Francisco dropped disproportionately to other modes. On-demand transit metrics helped SamTrans understand shifting travel behaviors and boost bus ridership by 30% after adjusting bus schedules.
When installing new infrastructure such as a bike lane or pedestrian bridge, digital analytics help agencies prioritize high-impact locations to invest in multimode infrastructure. For example, one Parks & Rec group used O-D analysis to determine the daily number of bikeable trips (five miles or shorter) to a target destination, justifying their investment in a new trail and bridge facility.
Similarly ATCS used digital transportation analytics to develop a multimodal scoring system for DC DOT that would help them pinpoint infrastructure gaps and determine where new projects were most needed:
Want to learn more about how digital transportation analytics can power effective Complete Streets initiatives? See how on-demand traffic data supports:
Yoo Min Park and Mei-Po Kwan, “Understanding Racial Disparities in Exposure to Traffic-Related Air Pollution: Considering the Spatiotemporal Dynamics of Population Distribution.” Int J Inviron Res Public Health 17 (Feb 2020): 908.
U.S. DOT, “Complete Streets,” August 2015.
Kea Wilson, Streetsblog USA. “Three Ways DOTs Can Help the Unhoused – On and Off the Road.” February 23, 2023.
Federal Highway Administration (FHWA), “Make Complete Streets the Default Approach.” February 2023.
Make streets safer with data-informed infrastructure planning
Explore the resources listed above and don’t hesitate to reach out if you have any questions. We’re committed to fostering a collaborative community of transportation professionals dedicated to building a better future for our cities and communities.
Corridor Studies Explained: What they are and how analytics make them quicker and cheaper
Corridor Studies Explained: What they are and how analytics make them quicker and cheaper
Corridor studies create crucial insights that keep people and goods moving safely, but they also demand ample resources from agencies already grappling with budget and staff limitations. On-demand analytics streamline data collection, offering a quicker and less costly path to the insights that inform corridor improvements.
When it comes to mobility, not all roads are created equal. That’s why transportation professionals devote considerable time and resources to major corridors — like interstates, state routes, and other major thoroughfares — to ensure people and goods can get where they need to go safely and efficiently.
To understand how mobility can be improved or maintained along these major arteries of travel, corridor studies are essential. They enable transportation professionals to understand existing conditions, project future conditions, prioritize improvement projects, earn stakeholder and public buy-in for these projects, and ensure environmentally-friendly transportation systems.
These outcomes are so important that corridor studies are often required under federal and state regulations before transportation projects can be approved or funded. But these studies are also demanding, unwieldy, and time-consuming for those who carry them out. They typically take several months or even years to complete, which can deplete already-thin agency budgets and frustrate constituents who want to see action.
So what is a corridor study exactly, why are these studies so important, how are they conducted, and how can technological innovations help shorten timelines, lower costs, earn stakeholder buy-in on projects, and deliver a fuller picture of corridor connectivity? We explore all these questions below.
What is a corridor study?
A corridor study is a planning project that aims to characterize existing and future roadway conditions along a major connective roadway (i.e., corridors) used by vehicles, bicycles, transit, and pedestrians. The scope of a corridor study may be hyper-local (a few miles or less) or it may account for dozens of miles of roadway, as is often the case when studying a major interstate.
Interstates and other major connective highways are the most common subjects of corridor studies.
Corridor studies are often multi-purpose projects that support a wide range of transportation goals such as:
Improving Operations
Economic Growth & Stability
Sustainability & Resilience
Safety & Equity
Communication & Public Relations
Meeting Regulatory Requirements
Estimating roadway capacity
Accommodating freight movement
Ensuring resilience against climate change, natural disasters, and general deterioration
Revealing safety concerns and potential improvements
Gaining community buy-in for proposed projects
Satisfying regulatory requirements for a project that is already planned for a funding cycle
Quantifying and minimizing the environmental impact of travel
Addressing inequitable infrastructure
Minimizing impacts to the traveling public during implementation
Estimating costs of maintaining or improving a corridor
Developing a travel demand model to help forecast future travel conditions
Expanding multimodal access and designing Complete Streets
Assisting other transportation agencies like MPOs and RPOs in identifying future projects along a corridor
The outcome of a corridor study is typically a corridor plan, which lays out recommendations for infrastructure projects and operational changes that address concerns revealed by the study. Along with these recommendations, a corridor plan usually includes estimated costs for the proposed measures as well as potential sources of funding to cover those costs.
To encourage a transparent planning process with buy-in from the public and other stakeholders, study findings and recommended projects are typically shared with partners, regional governments, advocacy groups, and the public through a published report.
Long-Range Corridor Plans
This type of corridor plan typically studies a major interstate or other highway and aims to establish justification for upcoming improvements, which may be implemented at a much later date (sometimes 10 or more years after the plan is created). In many cases, the plan is designed to address requests tied to political interests.
Long-range corridor plans are often conducted on a recurring basis (e.g., every 10 years or so) to keep up with shifting travel demand and offer guidance to DOTs, MPOs, RPOs, and other stakeholders who may design or carry out corridor improvements recommended by the plan.
NEPA Corridor Plans
The National Environmental Policy Act (NEPA) requires federal transportation agencies to report on the environmental impact of proposed projects, such as the construction of highways and other publicly-owned facilities. These reports must include an exploration of alternatives to demonstrate why the project proposed is the best available option.
NEPA corridor plans help avoid unforeseen environmental consequences of corridor projects, such as increased risk of erosion.
A NEPA corridor plan is usually established once a project and set of projects along a corridor has been planned for a funding cycle (to be funded within 10 years). As part of the planning process, public review must be sought out and incorporated in order to satisfy NEPA requirements so that funding can move forward and projects can be implemented.
Sometimes projects are put on hold and the NEPA process languishes. In this case, when it is restarted, NEPA needs to be revisited along with any updates to existing conditions and forecasts. This is particularly true when a large funding stream becomes available.
Metropolitan Corridor Plans
MPOs regularly plan for network and corridor improvements in their region as part of their Metropolitan Transportation Plan (MTP). These corridor plans are often ongoing and evaluate many iterations of projects and project portfolios in their MTP.
If a project is not indicated with dedicated funding in a MTP, then it can’t receive federal dollars. MTPs are made for rolling 20-year periods and updated every five years.
While MTPs are typically managed and developed internally by large MPOs, AEC firms may be contracted to assist with planning and coordinating public involvement. AEC firms or research institutes may also assist in modeling and data collection. Project funding and later activities are typically provided by the state.
City/County Corridor Plans
A city DOT or Planning Department will also initiate more localized corridor planning activities. These may be done in coordination with the MTP, federal, and state funding processes or as part of local funding efforts. As with other types of corridor plans, AEC firms are often called upon to help with the planning process and public outreach.
These projects often support goals related to Complete Streets, access management, economic growth, safety, traffic signals, and local transit.
Streamline corridor analysis with on-demand metrics like VMT, VHD, Trip Speed, and more
In order to evaluate existing conditions and forecast travel demand on a corridor, a wide range of data must be collected. Traffic volumes for all vehicles, as well as bicycles and pedestrians, are just the beginning. Turning Movement Counts (TMC) at intersections, Origin-Destination (O-D) patterns showing how travelers use the corridor to get from point A to point B, and congestion metrics may also be collected. Additionally, analysis will typically include estimating LOS, VHD, VMT, Crash Rates, and Reliability Indexes.
Traditional data collection methods for corridor studies include:
Field observations
Staff are sent out to multiple locations along the corridor to collect roadway inventory and measure geometries
Roadway sensors
Sensors collect traffic counts, speeds, and turning movements
Crash reports
Existing crash report data is reviewed and used to derive crash rates and flag safety issues
Data from previous transportation studies
Past studies of the corridor are reviewed for additional insights and can help demonstrate change over time
Physical roadway sensors may be installed on roads to help measure traffic.
Because of the time and cost that goes into many of these traditional methods, transportation analytics are often used to supplement and streamline these measurements. Given the difficulty of collecting data across a large area — such as traffic counts for a whole interstate — not only do analytics save time and money, but they also allow transportation professionals to get a consistent snapshot of a corridor at the same point in time and from different perspectives. Multiple analyses can be run in minutes, and data can easily be segmented by factors like time of day or day of week.
Despite these advantages, analytics typically do not replace traditional methods entirely. For example, in order to assess conditions such as roadway geometry, guiderail erosion, and sight distance, manual field observations are often necessary. However, software-based analytics are often indispensable in deriving data like Vehicle Miles Traveled (VMT), TMC, VHD, and O-D patterns for a corridor.
Input from stakeholders and the public is also gathered during the study. This helps identify community priorities, provide insight into who the corridor serves, and inform viable projects. Since getting the public on board with upcoming projects is a key concern for corridor planners, these insights are crucial for developing data-backed recommendations that justify proposed plans.
The data that is collected may also be used to build travel demand models that help forecast future conditions along the corridor.
How analytics are making corridor studies easier and more complete
Because corridor studies combine so many elements and may inform decades of infrastructure projects, they often take months to years to complete, demanding considerable cost and effort along the way.
While total study costs vary dramatically based on the size of the corridor, hundreds of thousands of dollars are typically devoted to the process. For example, a 2020 corridor study by VDOT studying under three miles of roadway cost $100,000[1], while a study of just 4.7 miles of SR 303 in Bremerton, Washington, was budgeted at $500,000.[2] Corridor studies often cover much larger areas than these two examples, and thus costs escalate quickly.
Although certain data must be collected manually in the field, software-based transportation analytics can significantly streamline data collection, while providing a more holistic account of roadway conditions like traffic volume, congestion, O-D, and turning movements. Because historical data can be accessed on demand for any day of the week, time of day, or month of the year, these analytics offer a more complete view of roadway conditions than temporary sensors or manual field observations gathered over just a few days.
This Segment Analysis in StreetLight InSight® shows Vehicle Miles Traveled (VMT) along a corridor, segmented hourly with peak hours highlighted.
Additionally, on-demand analytics contribute to a more holistic understanding of roadway safety. Traditional safety analyses rely heavily on information from reported crashes, missing nuances from crashes which may not be reported and unsafe incidents which don’t result in crashes.This can provide an incomplete view of factors contributing to unsafe corridors and make it more challenging to pinpoint sections of roadway where safety improvements could make the biggest impact. But when corridor studies incorporate transportation analytics, factors like speed, bike and pedestrian activity, and turning movements by time of day or day of week can provide additional insight to inform safety solutions.
This sample analysis in StreetLight InSight® shows trip speeds along multiple road segments.
By incorporating Census data to overlay aggregated demographic info on other corridor data, on-demand analytics also assist planners and engineers in identifying existing inequities and proposing improvements that address these disparities so that corridors serve everyone. Traditional methods of data collection miss out on this equity lens, making it harder for transportation professionals to ensure equity-first infrastructure.
For example, a steering committee conducting a corridor study of PA Route 28 used StreetLight InSight® to analyze the geographic spread of the home locations of travelers, helping reveal who the corridor serves. The committee also leveraged StreetLight to understand trip purpose, O-D patterns, trip duration, and trip speed.[3] Another study of seven key corridors in Hartford, Connecticut, used StreetLight InSight® to collect travel patterns, including O-D and trip volumes by time of day.[4]
And analytics don’t just help with establishing existing conditions. Because of the additional nuance and granularity provided by on-demand analytics, this technology is also a boon for modelers looking to build complex travel demand models that help forecast future roadway conditions.
Additionally, analytics platforms can assist with NEPA plans by helping estimate emissions, reveal EV activity, and measure overall traffic on a corridor.
Finally, platforms like StreetLight InSight® assist planners in justifying proposed corridor projects to stakeholders and the public through data visualizations that put study findings into perspective.
So while analytics can’t replace the need for certain manual measurements and field observations, they can justify prioritization decisions for stakeholders and the public with validated data while saving time and money on data collection and modeling so transportation agencies can devote more time to designing and implementing safe, resilient, and well-operated corridors for all.
Virginia Department of Transportation, Shreve Road Corridor Study. December 2020.
Washington State Department of Transportation, SR 303 Corridor Study. May 2021.
Southwestern Pennsylvania Commission, Route 28 Corridor Study. November 2020.
Connecticut Department of Transportation, Greater Hartford Mobility Study Existing Conditions Report. December 20, 2021.
WEBINAR: See how on-demand analytics streamline corridor studies & clarify planning priorities
Explore the resources listed above and don’t hesitate to reach out if you have any questions. We’re committed to fostering a collaborative community of transportation professionals dedicated to building a better future for our cities and communities.
Before and After a Protected Bike Lane: How Multimodal Infrastructure Impacts Safety, Congestion, and Ridership
Before and After a Protected Bike Lane: How Multimodal Infrastructure Impacts Safety, Congestion, and Ridership
In the business district of North Kansas City, Missouri, planners envisioned a corridor where cyclists and vehicles could coexist safely. Would a protected bike lane increase bicycling and reduce speeding without causing congestion? A before-and-after study—powered by StreetLight analytics—reveals what happened.
In 2019, Armour Road in North Kansas City, Missouri, underwent a series of improvements. The new infrastructure added brightly colored crosswalks, pedestrian refuges, and a new protected bike lane.
The bike lane was separated from vehicle traffic by a floating parking lane running parallel to the road, as well as special buffers and markings—a design intended to keep cyclists safe.
This image shows workers installing the bike lane demonstration project.
North Kansas City promotes itself as a livable city with suburban character. Armour Road is a principal thoroughfare running through the city’s downtown and adjacent commercial area. The bike lane installation wasn’t a routine upgrade, but a core part of the city’s broader plan to invest in biking and walking infrastructure, accessible urban destinations, and a vibrant cultural and business scene.
In working toward their vision, the planners had multiple goals for the Armour Road bike lanes. They wanted to promote efficient travel, but also safety and a greater amount of biking and walking in the heavily trafficked district.
To see if the new infrastructure worked, StreetLight conducted a before-and-after study using StreetLight InSight®, an on-demand mobility analytics platform. The study analyzed whether three of the stated policy goals of the Armour Road project were achieved. Specifically, did the bike lane:
Encourage biking so it makes up a greater overall share of traffic volume
Lead to a safer corridor with less speeding
Improve or at least maintain travel times
Planners can use StreetLight to complement more expensive, traditional methods of measuring traffic volume and vehicle speeds, such as direct observation, surveys, and counters. In this instance, there were several advantages to using StreetLight’s analytics for a data-driven, self-serve approach:
First, we were able to easily run multiple analyses to account for the possible distorting effect of 2020 pandemic restrictions. The bike lane was completed in late 2019, so our analyst ran the “before” data for the months of January to March of 2019. Although the obvious approach would have been to compare that data to the same period in 2020 (as the “after”), the tail end of that interval was affected by pandemic-driven lockdowns and altered traffic patterns. So we ran the data for January to March of 2021 as well, resulting in three sets of data to compare.
Second, we were able to inexpensively compare Armour Road data to a control road in the study area. Using StreetLight’s platform, the analyst measured bike activity on East 21st Street, a nearby road that runs parallel to Armour Road, to see if the new bike lane pulled in bike activity that would have happened elsewhere or actually increased biking activity overall.
Third, StreetLight captured nighttime bike volume that traditional methods usually can’t measure. Because traditional techniques often only operate well in daylight or business hours, they can miss a significant slice of volume. Later analysis showed that 15% of bike usage on Armour Road happened in night hours between 7 p.m. and 7 a.m., which likely would have been missed with traditional data collection.
Finally, StreetLight’s platform allowed for quick, multimodal snapshots and a synthesis of metrics tied to very different dimensions, including traffic share, safety, travel times, and congestion rate.
A visualization from StreetLight InSight® of bike volume on Armour Road from the 2019 study period shows how the distribution of volume (shown by the yellow line) peaks near midday but shows significant volumes in other parts of the day such as late evening, when traditional data collection is difficult.
The safety question was high among planners’ concerns.
As StreetLight Speed Metrics confirm, in 2019 drivers were speeding on Armour Road, with as many as one in every 20 car trips down the corridor moving in excess of 40 mph (miles per hour), despite a posted speed limit of 25 mph. After project implementation, the share of drivers going above 40 mph dropped to almost 0, significantly reducing the risk that pedestrians will be killed or seriously injured in the event of a crash.
As planners know all too well, higher vehicle speeds lead to an exponentially higher probability of severe injury or death in vehicle collisions with pedestrians. A widely cited AAA study shows that in the U.S., the average risk of severe injury for a pedestrian struck by a vehicle reaches 25% at 23 mph, but is three times higher, 75%, at 39 mph. The chance of death for pedestrians struck by a vehicle is on average 10% at 23 mph and 50% at 42 mph.
Ideally, a safer Armour Road would see less speeding without a significant increase in travel times or congestion.
Of course, the main purpose of bike lanes isn’t simply to slow down speeding cars—it’s to encourage bike activity. And planners wanted to make progress on the city’s goal of encouraging bike use.
The before-and-after: Reduction in speeding, doubling of bike traffic, and more
As hoped, bike traffic on Armour Road increased its share of the traffic-volume pie, according to StreetLight’s measurements.
Before the bike lanes, in early 2019, bikes accounted for only 1% of the daily trips on Armour Road. In early 2021, biking’s share had grown to 2%. That may seem like a modest increase but represents a significant uptick in day-to-day bike travel: there were around 50 daily bike trips on average passing through the study sites along the corridor in early 2019. In 2021, after the protected bike lane went in, that number more than doubled to 114.
But was this the result of cyclists from other neighborhoods and bike routes being attracted to the upgraded Armour Road corridor? Or is there evidence that some of the biking would not have happened without the bike lanes?
As mentioned, that’s where the control data became useful. While less trafficked overall than Armour, the control segment on East 21st Street saw a proportional increase in bike traffic between 2019 and 2020 (though it remained flat between 2020 and 2021). The lack of a decrease in biking on East 21st Street supports the hypothesis that the new bike lane led to an overall net increase in biking’s adoption in the study area, rather than simply funneling in preexisting bike traffic.
In terms of safety, the most significant safety improvement was possibly a life-saving one. The bike lanes led to the near elimination of the most dangerous speeds—vehicles traveling above 40 mph, which had previously been roughly 5% of vehicles.
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.
As for congestion, which is measured in several ways, it saw a slight increase. When looking at congestion rate, or the proportion of hours of the day in which congestion occurs, there was an uptick from 13% to 20% between the 2019 and 2020 study periods. In 2021, however, the congestion rate slipped back to 18%.
But did this congestion meaningfully impact travel time?
Travel time data showed that vehicle trips through the corridor were taking on average 124 seconds in 2019, and 129 seconds in 2021, an increase of only 5 seconds. The travel time data indicates that the uptick in congestion isn’t having a substantial impact on travelers’ trip length.
Tracking holistic infrastructure goals
When designing their vision and plans for Armour Road in 2016 and 2017, North Kansas City planners drew on Complete Streets, a transportation planning approach that helps cities and towns build safe and accessible mobility corridors that open up opportunities for biking or pedestrian traffic.
The approach targets more than one goal: it values safety, but also ease of use, efficient travel, connectivity, and equity.
In other words, Complete Streets is a multidimensional and holistic approach. And that makes the choosing and analyzing of metrics more challenging.
This view of the Armour Road bike lane area visualizes improvements made in a downtown segment of the road as part of the 2017 Armour Road Complete Street implementation plan.
Due to limitations on staff time and the preventatively expensive nature of traditional methods, planners don’t typically measure before-and-after data to determine if a roadway improvement succeeded.
That’s why a mobility analytics-based approach is a helpful alternative, allowing on-demand before-and-after studies.
StreetLight processes vast amounts of location data from connected devices and contextualizes the data using parcel data and digital road network data. Finally, StreetLight’s Data Science team has developed proprietary methods to expand the sample and create reliable, validated Bike and Pedestrian Volume estimates.
The end result is a repository of multi-modal traffic patterns across North America’s vast network of roads, bike lanes, and sidewalks. This repository can be consulted for multimodal volume estimates, congestion rates, travel times, and more, for any period of time, on any facility, on demand.
This versatility allows planners a great deal of freedom in analyzing a diverse set of factors when conducting before-and-after studies, without needing to plan ahead to collect that data.
It also can lead to surprising revelations and, thus, more informed planning. For example, the finding that a significant share of bike activity happens at night could help planners focus on measures to ensure overnight safety.
Why before-and-after studies are so important for infrastructure planning
Traditional data collection methodologies have made it challenging to study the impact of changes to the built environment. Mobility analytics solve this challenge by allowing retroactive analysis. Planners can then build up a strong repository of empirical evidence on what does and doesn’t work for infrastructure planning.
This data can also shape public perception of infrastructure planning. Without real-world evidence of what a particular planning decision’s impact will be on the community, it’s easy to misdiagnose projected outcomes. The more data we have on how similar investments perform, the easier it becomes for practitioners to make informed decisions about their priorities and effectively explain those priorities to the government leaders and constituents they serve.
In the case of the Armour Road bike lane, the outcomes of this project—additional bike activity and limited congestion increases—can inform other localities’ planning and communication.
The Hidden Deficit Holding Back Bike Infrastructure Investment? Data.
The Hidden Deficit Holding Back Bike Infrastructure Investment? Data.
For decades, vehicle-centered metrics have dominated transportation planning. But that’s changing. There’s increased public interest in biking, and federal dollars are available for new pedestrian and bicycle projects. Planners need to broaden their lens to keep up.
“It’s kind of scary actually, how little we know about our communities, when it comes to walking and biking transportation,” said Bill Nesper, executive director of the League of American Bicyclists, speaking at StreetLight’s Bike Infrastructure Roundtable.
That lack of data is a function of a historical prioritization of driving measurement. And without information on active transportation activity, it’s extremely challenging to know where to invest in infrastructure that can promote safe and more widespread riding.
But that lack of measurement is beginning to change and it will have an outsized impact on the capacity to make better and safer active transportation investments.
Nesper, alongside Bike Infrastructure Roundtable panelists Jackie DeWolfe of massDOT, Amanda Leahy of Kittelson & Associates, and Jeff Peel of StreetLight, focused on challenges in assessing bike and pedestrian traffic — and how those challenges are starting to be overcome. Below, we discuss how participants on the panel see the active transportation information landscape shifting, and how better measurement can help push biking and walking infrastructure forward.
The fundamental challenge is data availability. While the situation is steadily improving, most jurisdictions work with scant information on bicycling and walking activity.
With thin sources from which to draw out metrics and insights, it’s difficult to prioritize new or improved bike networks, not to mention substantiate an expected return on investment.
And, data that is available typically comes from temporary counters along select existing bike paths and trails, or surveys. These are often scant, and difficult to use to extrapolate a complete picture of biking activity across a region, let alone compare to historical activity.
They are also of limited usefulness when it comes to calculating the potential of new facilities or metrics dependent on context, like climate benefits, or understanding bike projects’ equity profiles.
The problem boils down to “data parity,” or the lack of it. Bike, pedestrian, and other alternative transportation modes are up against the stark fact of a planning landscape dominated by the data cars and trucks throw off.
“For vehicles we have thousands of counters, connected vehicles, and location-based data that provide robust information,” said Jackie DeWolfe, director of sustainable mobility at the Massachusetts Department of Transportation or MassDOT. “And we need the equivalent of that for all modes. Luckily, there’s a lot happening, and there’s future promise for big data to provide that.”
Billions for bike infrastructure up for grabs in five-year push
The stakes are especially high given the Bipartisan Infrastructure Law or BIL, passed in 2021, which earmarks billions for transport improvements. That includes the Safe Streets and Roads for All program, which will award $5 billion annually to states and cities over five years. The grants aim to limit roadways deaths and injuries, including by creating accessible “bikeway networks” and safe bike routes to schools.
Other bike- and pedestrian-relevant funding programs include grants for carbon-reducing efforts and a program known as Reconnecting Communities. The latter program is described by Transportation Secretary Pete Buttigieg as “the first-ever dedicated federal initiative to unify neighborhoods living with the impacts of past infrastructure choices that divided them.”
League of American Bicyclists won inclusion of BIL spending towards data to support connected network projects.
To firm up grant applications, planners will want to include data and evidence that supports their view of the expected benefit. — Amanda Leahy, associate planner at Kittelson & Associates.
For the BIL programs and other federal and state initiatives, funders want to see quantitatively rigorous analyses to complement qualitative narratives.
Leahy, along with the other panelists, shared examples from Kittelson’s own experience to show how projects can target not only immediate impacts such as changes in travel habits or time- and cost-savings, but also other effects as studies draw on broader qualitative or demographic data sets. These include changes in safety and crash indices, climate impact, and supporting equitable transportation options.
Leahy cited a project that used data to demonstrate measurable health benefits and healthcare cost savings from active transportation investments. Being able to show this kind of ROI is critical to getting community buy-in on active transportation investment, as well as grant funding.
Later she mentioned bike infrastructure’s impact on neighborhood housing costs as another significant metric to weigh.
Measurement sources are tremendously useful here as they offer regular “access to information on how people are traveling, and this helps overcome limitations with more lagging data or less comprehensive data,” said Leahy.
Several panelists commented on the incomplete and outdated data contained in state or national surveys widely used by transportation planners, including the Federal Highway Administration’s National Household Travel Survey.
Most obviously, pre-2020 data does not cover the emergence of Covid-19 and ensuing changes. The pandemic suppressed commuting behavior, led to a boom in biking and walking, and shifted peak travel times. Some of those changes — like the increased adoption of biking — have persisted.
Beyond years-old surveys, the most advanced transportation agencies rely heavily on permanent counters deployed along principal bike paths. They then attempt to infer broader trends from the metrics tabulated from those few counters.
“While those counters get great results, they are limited to the locations and types of travel they are capturing,” said Jeff Peel, a customer success account executive at StreetLight and former deputy director transit at NYCDOT.
In fact, because these counters are sometimes placed in highly trafficked areas, they can support circular logic and planning biases.
Jackie DeWolfe, of MassDOT, mentioned how the preexistence of bicycling and pedestrian activity is sometimes cited as a reason not to place biking and walking infrastructure such as a bike lane or safety crossings on those corridors (the thinking is that there’s no need for additional investment in infrastructure if the behavior is already present).
Instead, DeWolfe said, planners should simply be on the lookout for areas where they can have the most impact.
“That’s why we are actually prioritizing infrastructure based on the potential for biking and walking, not based on counts,” she said.
Map of high to low potential biking activity in Massachusetts.
A broader lens on transportation thanks to better analytics
To study walking and biking potential, MassDOT planners have to take in a broader view of study areas to help them understand the relationship between different neighborhoods and how bikers and walkers move through them.
That is why StreetLight has been crucial in this effort. StreetLight ingests, indexes, and processes vast amounts of data from connected devices and the Internet of Things, then adds context from numerous other sources like parcel data and digital road network data – to develop a view into North America’s vast network of roads, bike lanes and sidewalks.
Equity: They are able to evaluate equity factors more comprehensively, since they are able to understand behavior across the state without making coverage tradeoffs and compare a large number of locales for considerations tied to demographics.
Location: Relatedly, they are able to encompass far more locations, since data collection is not reliant on fixed points of collection, e.g. counters that only measure segments of a journey.
Parity: As mentioned, planners are usually working with a dearth of multimodal data when compared to what is available on vehicle traffic. The big data sources allow them to consider modes like walking and biking on a more even playing field compared to vehicles, which otherwise dominate data sets.
To illustrate the advantages of a broader data palette, the planners shared examples and case studies.
DeWolfe gave an example from the pandemic’s early days. Having StreetLight, MassDOT planners were able to follow along almost in real time as traffic patterns quickly changed. They immediately saw how walking and biking activity shot up. Unfortunately, so did car speeds. Data showed a “horrible” deterioration in safety.
Planners responded with more than $30M in spending for safety fixes for scores of corridors across the state.
“This was just huge,” said DeWolfe. “Otherwise everything would have been focused on vehicle miles traveled. We were able to complement it with walking and biking activity and tell a different story.”
Importantly, DeWolfe pointed out that counters — temporary or permanent — are a part of the portfolio of data sources used by MassDOT, which includes field surveys and other methods as well. In fact, counters are useful in cross-checking and calibrating big data sources. In other words, the solutions aren’t mutually exclusive. Rather, they are most effective when joined together.
What do planners want to see more of as they build a larger ecosystem of active transportation infrastructure?
They cited a need for better integration of safety and crash-risk data, deeper qualitative studies on trip purposes, and more granular insight into demographic and equity trends.
Equity, in fact, is a thread that runs through the BIL and other relevant state and federal programs (although it tends to be defined differently in each instance). It’s expected to be a recurring topic for planners, driving demand for robust demographic and trip-analysis data.
As transportation agencies and Architectural, Engineering, & Construction agencies (AECs) get to work applying for and deploying BIL funds, data will be central to making a case for active transportation investment, measuring how conditions are changing in real-time to see impact, and assessing the demographics of beneficiaries to ensure equitable outcomes.
