Investigating how trucks impact social equity with new freight data
Investigating how trucks impact social equity with new freight data
How doestruck activity impact disadvantaged communitiescompared to their non-disadvantaged neighbors?StreetLight uses new truck data to show how you can investigate inequitable truck impacts in your community.
Truck activity can have a huge impact on local emissions and traffic congestion, but not all communities are equally affected. Now, new truck data from StreetLight helps analysts investigate how truck traffic impacts disadvantaged communities (DACs)across the U.S., and how factors like urban density, vehicle weight class, and industry type contribute – and help diagnose – inequitable impact.
Key Takeaways
In New York state, StreetLight’s data indicatesdisadvantaged communities are impacted by worse truck travel delays than non-disadvantaged communities,potentially exacerbatingnegative outcomes, such as air pollution and emissions.
Communities in the urban coreare the most impacted by truck travel delays and the added emissions and pollution they often generate.
Overall, medium-duty trucks show the most unequal impact on disadvantaged communities. Trucks in this category from the public administration and transportation and warehousing industries may warrant special attention for DACs.
Trucks are some of the worst offenders when it comes to vehicle emissions. Although they are indispensable to today’s freight logistics, they also emit more CO2 and other air pollutants than cars because they typically emit more GHGs per mile in addition to traveling much longer average distances.
Compounding trucks’ oversized climate impact is a dramatic spike in freight activity. A 2021 analysis by USDOT’s Bureau of Transportation Statistics predicted total U.S. freight activity would grow 50% by 2050, with trucks accounting for 65% of that total.1 This proliferation of truck traffic also challenges existing road capacity in many communities, exacerbating rising congestion and safety issues.
And these ramifications often come down hardest on disadvantaged communities — people who live in low-income neighborhoods where high congestion, noise pollution, and poor air quality are common. For this reason, analyzing how truck activity impacts disadvantaged communities is critical to reducing harms.
Now, freight planners, fleet operators, and businesses can use new truck data from StreetLight to understand how freight activity impacts different communities, as well as investigate related questions about who truck activity serves, which industries are most represented, and how travel delays impact logistics, emissions, and equity.
Below, StreetLight analyzes commercial vehicle activity in New York, comparing its impact on DACs vs. non-disadvantaged communities.
How Trucks Impact Disadvantaged Communities in New York
Since 2021, disadvantaged communities (DACs) have been a key focus of efforts to improve transportation equity. These communities are “marginalized by underinvestment and overburdened by pollution,” as defined by Executive Order 14096, which established the Justice40 Initiative, a policy promising to funnel at least 40% of federal investments in clean energy, clean transit, sustainable housing, and similar programs into low-income census tracts that qualify as disadvantaged communities.2
In the state of New York, about 36% of all census tracts — accounting for about 35% of the state population — are considered to be DACs.
While all truck traffic can negatively impact a community’s air quality, traffic congestion, and local emissions levels, analyzing how different weight classes impact DACs vs. non-DACs can add helpful nuance to planning efforts aimed at mitigating this impact and targeting policy interventions.
To unpack the impact of trucks on DACs. vs. non-DACs, StreetLight’s analyzed truck activity in New York state by weight class and how it differed in these community types. Streetlight finds that light-duty and medium-duty truck activity have a disproportionate impact on disadvantaged communities per mile. Meanwhile, heavy-duty activity per roadway mile is slightly higher within non-DACs.
Truck Activity Per Roadway Mile is segmented by commercial vehicle weight class to compare trucks’ impact on DACs vs. non-DACs. See our Methodology section at the end for more details.
Going further and factoring in travel delays among trucks, the picture changes substantially.
The chart below illustrates the inequitable impact of congestion, with DACs encountering significantly more traffic delays per roadway mile, even among truck classes that have a lesser presence in DACs compared to non-DACs. In fact, DACs are faced with more traffic delays across every class of truck, suggesting that DACs may also be exposed to disproportionately high emissions from both gas-powered and diesel-powered trucks as these vehicles linger through delays, contributing to poor health outcomes.
Measuring the average delay from free-flow speed per roadway mile reveals that traffic delays impact disadvantaged communities significantly more, regardless of which classes of truck are driving in their community.
While trucks are not necessarily the cause of these traffic delays, congestion mitigation efforts can still help reduce the impact that trucks — and indeed all vehicles — have on the communities they travel through.
Because these delays are averaged across the entire available roadway network, the per-mile delay impacts appear small. Nevertheless, the fact that average delays are higher for DACs than non-DACs suggests that analyzing congestion is a worthy step when evaluating the impact of truck traffic within disadvantaged communities.
While traffic delays are a nuisance for communities in and of themselves, lengthening commute times and making it harder to access essential goods and services, delays also intensify other negative impacts of vehicle activity like emissions and air pollution.
Where TruckDelays Have the BiggestImpact by Density
For agencies to manage truck activity in a way that improves transportation equity, it’s also important to understand that DACs are diverse in makeup, as are non-DACs – no two communities look exactly the same. For example, urban density can have a significant impact on how communities are impacted by trucks.
To understand these nuances, let’s first establish how DACs are distributed across different urban densities – from rural locations to the urban core.
The map above highlights important nuances to consider when comparing census tracts—firstly, rural census tracts cover far more area, and therefore far more roadway network miles, than urban tracts. For this reason, StreetLight normalizes Truck Activity by roadway mile for this analysis (see Methodology section for more details).
Furthermore, the map shows that DACs are concentrated in urban areas. Zooming in on New York City reveals just how many DACs call the city home compared to rural areas throughout the state. The chart below explores this distribution by population.
Since DACs are concentrated in urban areas, you might expect to find that truck delays are only an issue for DACs in urban and urban core locations.
However, in the chart below, we can see that while delays are worse in urban DACs, even in rural and suburban areas, DACs are impacted by more travel time delays than their non-DAC counterparts, highlighting the importance of targeting congestion mitigation efforts and improving freight planning within disadvantaged communities across all urban densities.
How Different Truck Weight Classes Impact Communities
To further contextualize StreetLight’s truck findings by density, let’szero in on the roles different truck weight classes play in each type of tract.
Truck Weight Class Distribution by Urban Density
How Different Industries Contribute to Truck Impact, by Weight Class
Given the disproportionate impactmedium-duty vehicles have on DACs by overall activity, and especially when factoring in travel delays, it’shelpful to understand what roles these vehicles play in communities, and which industries drive medium-duty truck activity.
As the image above depicts, commercial vehicles range from class 1 to class 8, with classes 1 and 2 considered “light-duty” vehicles, ranging from commercial vans to pickup trucks. Classes 7 and 8 are “heavy-duty” vehicles, including garbage trucks, city transit buses, and traditional semi-trailer trucks. Everything in between (classes 3-6) is considered “medium-duty,” ranging from local delivery trucks to school buses.3
Based on mileage, medium-duty truck activity in New York’s DACs is predominantly comprised of Public Administration and Transportation and Warehousing vehicles, with Real Estate and Rental and Leasing (the front-runner for medium-duty activity in non-DACs) trailing just behind.
Meanwhile, Real Estate and Rental and Leasing and Transportation and Warehousing also make a strong showing within the heavy-duty vehicle activity breakdown.Although heavy-duty vehicles show more truck activity per roadway mile within non-DACs compared to their DAC neighbors, these trucks still have a significant impact on DACs, especially as they contribute more emissions and noise pollution per mile traveled compared to smaller trucks. For this reason, understanding the industry breakdown among heavy-duty trucks could also generate valuable lessons for equity-focused freight planning.
Based on these findings, medium- and heavy-duty trucks serving the transportation and warehousing industrycould warrant special attention from freight planners. These trucksoften travel to and from larger hubs of freight activity, such as distribution warehouses and ports, making communities impacted by these high-traffic freight routes that much more likely to experience air and noise pollution due tonearby truck activity. Moreover, much of this truck traffic may not be ending in these communities, merely passing through. For this reason, the Bipartisan Infrastructure Law (BIL) provides special funding opportunities for decarbonization efforts that target ports.4
Key Takeaways for Managing Truck Traffic Impacts
To improve outcomes for disadvantaged communities, planners must consider the inequitable impacts of truck traffic as they work to mitigate congestion, reduce emissions, and route trucks efficiently.
StreetLight’s analysis highlights that some classes of truck impact DACs more than their non-DAC counterparts, suggesting that analyzing this truck activity and targeting electrification efforts toward these weight classes and industries in particular may help address inequitable impact and target the most impactful improvements.
Additionally, the analysis shows traffic delays are a problem disproportionately impacting DACs across all urban densities, but especially in the urban core. Though these delays are not necessarily caused by trucks themselves, they can exacerbate the impacts trucks have on local emissions and air quality, making efforts to mitigate congestion and route trucks more efficiently in disadvantaged communities especially critical.
Finally, the Transportation and Warehousing industry emerges as a significant contributor to trucks’ impact on disadvantaged communities. This industry could warrant special attention from planners or businesses looking to address freight’s equity impact. And for businesses with large logistics operations, placing emphasis on improved routing and electrification could mitigate congestion and emissions impacts on disadvantaged communities.
This analysis includes truck data for March 2024 within the state of New York, including residential roadways.
To measure Truck Activity, StreetLight analyzes sample Vehicle Miles Traveled (VMT) for commercial vehicles per mile of available roadway network in each census tract.
To analyze traffic delay, StreetLight uses a weighted average of travel time delay per mile of available roadway network in each of the urban density and DAC/non-DAC categories. The weight is the segment truck sample count, so that segments with higher numbers of trips have their delay represented proportionately. In other words, the travel time delay value for each of these categories represents how much delay a driver can expect when travelling one mile within that category.
StreetLight analyzes the urban density of census tracts based on the density of their roadway networks.
Census tracts are labeled “disadvantaged” vs. “non-disadvantaged” based on how they are classified by the Justice40 Initiative. In general, census tracts labeled “disadvantaged” meet a threshold for “environmental, climate, or other burdens” and “an associated socio-economic burden.”5
1. USDOT Bureau of Transportation Statistics. “Freight Activity in the U.S. Expected to Grow Fifty Percent by 2050.” November 22, 2021. https://www.bts.gov/newsroom/freight-activity-us-expected-grow-fifty-percent-2050
2. The White House. “Justice40, a whole-of-government initiative.” https://www.whitehouse.gov/environmentaljustice/justice40/
3. U. S. Department of Energy, Alternative Fuels Data Center. “Maps and Data – Vehicle Weight Classes & Categories.” https://afdc.energy.gov/data/10380
4. Office of Energy Efficiency & Renewable Energy. “Federal Funding Opportunities for Port Low- to Zero-Emissions Technologies.” https://www.energy.gov/eere/federal-funding-opportunities-port-low-zero-emission-technologies
5. Office of Energy Justice and Equity. “Justice40 Initiative.” https://www.energy.gov/justice/justice40-initiative
Ready to investigate trucks' equity impact in your community?
Public Data from NYCDOT Validates the Reliability of StreetLight’s Speed Metrics
Public Data from NYCDOT Validates the Reliability of StreetLight’s Speed Metrics
Access to accurate vehicle speed data is critical for effective road safety interventions, congestion mitigation, and more. We compared StreetLight’s speed metrics to data from New York City’s OpenData portal to ensure we’re delivering the most reliable insights.
To collect data on vehicle speeds, many agencies rely on permanent roadway sensors, speed cameras, or manual speed studies. But tight budgets and project timelines prevent the installation of sensors on every road, and manual studies only capture a small snapshot of roadway conditions, while also putting workers at risk.
Meanwhile, businesses and firms may not have access to the already limited speed data that is available via these methods, limiting their ability to make informed decisions about real estate, traffic operations, or events management.
For these and other reasons, many agencies, firms, and businesses turn to analytics platforms like StreetLight that leverage a big data approach to deliver vehicle speed metrics for any road, at any time. But when sourcing your data, it’s important to understand how reliable it is compared to more traditional ground truth methods.
Thanks to the City of New York’s OpenData portal, with publicly available vehicle speed data provided by NYCDOT, we were able to perform a validation of StreetLight’s speed data against New York City’s documented speeds. We’ll explain how our speed data is collected, how it compares to NYCDOT’s data, and what that means for your own vehicle speed analyses.
How NYCDOT Collects Speed Data
The speed data available in NYC’s OpenData portal is collected through E-ZPass readers located on approximately 110 road segments throughout the city. Vehicle speeds are calculated based on the travel time and distance between two E-ZPass readers.
This approach captures average vehicle speed in real time, and the portal is updated with the most recent data several times per day.1
How StreetLight Collects Speed Data
StreetLight’s Vehicle Speed metrics are derived from Aggregated GPS Data, which includes data from a blend of device navigation apps, traditional mobile data apps, and in-vehicle navigation apps.
This method has the advantage of strong penetration rates across various road sizes and regions for a highly representative sample, even on rural and lower-volume roads. StreetLight’s sample penetration rate averaged 27% nationally in 2023 and was observed as high as 40%+ in some locations.
To develop segment-level speed metrics, StreetLight maps this data onto the StreetLight InSight® Zone Library, derived from OpenStreetMap (OSM). Based on the length of the segment and how long it takes a vehicle to travel from one end to the other, we estimate the average vehicle speed along that segment.
For more information on how StreetLight collects, aggregates, and validates our vehicle speed metrics, you can download this white paper. To integrate speed and volume data into your own platforms, check out our Traffic Data API.
Comparing the Data: How Accurate Are StreetLight’s Speed Metrics?
To ensure an apples-to-apples comparison, StreetLight analysts first cleaned the NYCDOT data, removing certain obviously incorrect datapoints that may have been caused by malfunctioning E-ZPass readers. Next, the cleaned NYCDOT data was aggregated such that the mean speed could be calculated per segment by day of week and hour of day.
Using StreetLight’s Network Performance analysis, analysts obtained the average speeds of groups of OSM segments that aligned with NYCDOT’s segments, looking at data for October 2023. This allowed for a close comparison between StreetLight and NYCDOT average speeds on 11 NYCDOT segments.
In this example comparison for a portion of FDR Drive Northbound, analysts averaged vehicle speeds from 10 StreetLight OSM zones (middle) aligned to the corresponding NYCDOT segment (left). On the right, NYCDOT speeds by day and time are marked with a blue line, while StreetLight speeds are marked in yellow.
Because StreetLight’s OSM-based segments do not have a one-to-one correspondence with NYCDOT’s segments (which are derived based on the distance between E-ZPass readers), special care was taken to align StreetLight segments with those used by NYCDOT, but some discrepancies persist, which we will discuss further in the analysis below.
Speed comparisons by day of week and hour of day for RFK Bridge Southeast Bound (left), Staten Island Expressway Eastbound (middle) and Long Island Expressway Westbound (right) segments. Monthly Average Daily Traffic (MADT) for each segment is marked below its graph.
Speed comparisons for Bronx Whitestone Bridge Southbound (left), Gowanus Expressway Southbound (middle), and FDR Drive Northbound (right).
Speed comparisons for Bruckner Expressway Westbound (left), Brooklyn-Queens Expressway (BQE) Southbound between Atlantic and 9th St (middle), and the Brooklyn Battery Tunnel Eastbound (right).
The above nine segment analyses showed StreetLight speed metrics closely aligned with speed data reported by NYCDOT. Where the data differs, StreetLight speeds tend to be slightly higher than those reported by NYCDOT.
Overall, StreetLight’s daily and hourly speed variations for each segment also track closely with the NYCDOT data, indicating that StreetLight’s speed metrics deliver reliable insights for real-world applications like safety and congestion studies, which can save agencies the considerable cost of installing physical sensors.
The two remaining segments (pictured below) display the greatest divergence between the StreetLight and NYCDOT datasets.
Speed comparisons for 12th Avenue Southbound (left) and Lincoln Tunnel Eastbound (right). These graphs show segments where StreetLight’s OSM zones could not be perfectly aligned to NYCDOT segments.
These discrepancies are likely caused, at least in part, by misaligned segment boundaries. As discussed above, sometimes StreetLight OSM zones could not be perfectly aligned to the NYCDOT segments.
In the case of 12th Avenue (AKA West Side Highway), this segment is part of a signalized corridor with closely spaced intersections, which could exacerbate the impact of the misaligned segments. Because the comparison segments do not have the same signalized-intersection approaches, this could lead to larger differences in average speed.
Despite these localized limitations in segment comparability, the overall results of our comparison show a high degree of alignment between StreetLight’s big data-based speed metrics and NYCDOT’s speed data derived from E-ZPass sensors.
More about StreetLight’s Vehicle Speed Data – Segment Speed and Spot Speeds
Because the vehicle speed metrics provided by StreetLight include average segment speeds, they can provide a helpful perspective, even for agencies that already collect speed data through physical sensors.
Unlike NYCDOT’s average segment speeds used in the above analysis, the speed data available to most agencies are spot speeds. Spot speeds capture vehicle speed at a specific location rather than the average vehicle speed along a whole segment.
Spot speeds and segment speeds each capture a different nuance of vehicle traffic, and comparing the two can help agencies better understand the causes of unsafe speeds or congestion, as well as their most effective solutions.
To ensure clients can take advantage of these nuanced speed insights, spot speeds are now available from StreetLight! To stay updated on all our product releases, consider subscribing to our newsletter.
1. City of New York. NYC OpenData. “DOT Traffic Speeds NBE.” https://data.cityofnewyork.us/Transportation/DOT-Traffic-Speeds-NBE/i4gi-tjb9/about_data
How Can We Reduce Emissions From Urban Transportation?
How Can We Reduce Emissions From Urban Transportation?
Emissions of greenhouse gases (GHGs) and other pollutants are a pressing concern for environmental and human health. Despite recent declines in the U.S., the global level of emissions remains at historic levels, leading to alarm among public health advocates and climate change activists alike. [1]
Although there are many factors behind these historically high emissions levels, none is as significant as transportation. In the U.S., the transportation sector accounts for 29% of all GHG emissions, ahead of even electricity generation and industry. [2] These emissions are highly concentrated in urban areas. According to the United Nations, 60% of GHGs come from cities, where cars and other modes of transportation relying on Internal Combustion Engines (ICE) are especially prominent. [3]
This makes urban transportation a strategic target for reducing emissions and curbing their impact on the environment and public health. The good news is that more than 10,000 cities have already committed to reducing carbon emissions by 2050. [4] Still, if history is any indication, curbing transportation emissions is easier said than done. Ultimately, city planners, transportation agencies, and many other stakeholders must come together with a strategic plan.
What will it take to reduce emissions from transportation, and just how important is this task? In this article, we’ll explore:
The cost of urban emissions
Shifting the urban transportation paradigm
Picturing the future with big data
The Cost of Urban Emission
Emissions are more than a nuisance — they exact a heavy toll on the global economy. In the U.S. alone, pollution accounts for around 5% of the nation’s gross domestic product in damages each year, or $1.3 trillion in 2023. More than mere dollars and cents, however, the costs of pollution are particularly prominent in terms of public and environmental health. [5]
Damaging Public Health
By any estimation, pollution is a serious public health concern. According to one in-depth study, fine particulate matter from numerous toxic pollutants contributes to between 100,000 and 200,000 deaths in the U.S. each year. The transportation sector is responsible for the second-largest number of these deaths, behind only industrial and commercial activity. [6]
No matter who is involved, such a large number of deaths is tragic. Yet, the tragedy is made worse by inequity, as pollution disproportionately impacts already vulnerable Americans. Children, pregnant people, older adults, people of color, and those living in poverty are among those most at risk for adverse outcomes from pollution. [7]
Transportation emissions are a primary source of city smog impacting residents’ health.
Accelerated Climate Change
GHG emissions are the single largest contributor to climate change since the mid-20th century. [8] Research has connected emissions from human activity to a host of environmental events, including temperature extremes, surges in precipitation, more frequent droughts and wildfires, and more devastating weather patterns.
The risk of these events continues to grow, and the Intergovernmental Panel on Climate Change (IPCC) warns of serious peril for major ecosystems if global temperatures aren’t brought under control. If global averages reach temperatures of at least 1.5 degrees Celsius above pre-industrial levels, the effect on human, plant, and animal life may be irreversible, even catastrophic. [9]
Shifting the Urban Transportation Paradigm
In light of such devastating consequences, reducing carbon emissions is becoming a top priority for many involved in public policy and planning. Urban transportation represents an important target for these changes, as small adjustments in this sector could have an outsized impact on reducing pollution.
Realizing these outcomes requires three critical shifts in how we approach transportation in urban areas.
Move People First, Not Cars
The first and most important step in reducing urban transportation emissions is to shift away from a car-centric approach to transportation planning. The purpose of any type of transportation is to move people from one place to another, but many of our cities focus on moving cars.
Instead of merely building more and wider roads designed only for vehicles, planners can focus on building complete streets — ones that make room for all kinds of commuters, including pedestrians, bikers, and users of public transit. Centering multimodal transportation will help incentivize and enable more commuters to use these alternative methods.
Reducing reliance on household vehicles could have a substantial effect on urban emissions. According to the United Nations, each person who switches from cars to public transport could reduce their carbon emissions by up to 2.2 tons per year. [10] Another study shows that while public transit cuts GHG emissions by 58% compared to cars, cycling lowers them by 98% — meaning both offer substantial emissions reduction potential. [11]
The more transportation planners can leverage detailed data to inform their plans for new or updated roads, the more effective these changes can be. For instance, planners in Oregon’s largest special park district, the Tualatin Hills Park & Recreation District, were able to use detailed origin-destination data to confirm the value and potential impact of installing a bike-pedestrian bridge to move more commuters over a busy highway — without adding more car traffic.
See what emissions reduction tactics your city needs most
Although it’s possible to reduce emissions and other urban transportation problems by shifting the focus away from vehicles, it’s not feasible to entirely eliminate the need for cars in our cities. Where they are still needed, then, it’s critical to accelerate the move toward electric vehicles (EVs) and away from gas-powered vehicles.
One recent study showed that adopting EVs would reduce carbon emissions significantly in every state. In states like Washington or Vermont, which already rely on clean electricity sources, EV usage could reduce pollution from carbon emissions by more than 90%. Even in states like Kentucky and West Virginia, where electricity generation relies heavily on fossil fuels, emissions would drop by over 30% with a full transition to EVs. [12]
With more federal support for the EV initiative than ever, now is an ideal time for cities to encourage drivers to increase fuel efficiency and electrify their driving. In addition to the National Electric Vehicle Infrastructure (NEVI) grant program introduced by the Bipartisan Infrastructure Law (BIL), massive federal tax credits are also available for EVs and chargers, and many cities and states are taking a step further by providing credits of their own or encouraging utility companies to create rebate programs and other incentives. Cities themselves can also leverage such programs to expand public charging installations and electrify public transit.
Public EV chargers in cities help overcome barriers to accelerated EV adoption.
Rethink City Planning
As essential as investments in electrification and multimodal transportation are to reducing carbon emissions, they aren’t sufficient solutions to the problem. Urban planners must think bigger, considering land use, transportation, operations, policy, and more in a comprehensive approach to emissions-reducing city planning.
With a holistic view, city planners can make progress by focusing on initiatives such as investing in green buildings, expanding renewable energy production, and improving waste management. [13] They can also consider the best ways to invest in tomorrow’s transportation infrastructure.
This requires thoughtfulness and intentionality. The BIL provides historic levels of funding for cities to upgrade their transportation infrastructure, but studies show that these investments could actually lead to increased emissions if not used properly. For instance, the Georgetown Climate Center recommends that planners focus on a “fix it first approach” of maintaining existing roads and investing in public transit, EVs, and other low-carbon options — rather than building more roads or expanding existing ones, which could induce demand and bring more pollution. [14]
Again, choosing the right updates and planning initiatives requires access to extensive data, both in terms of transportation patterns and existing urban emissions levels. Only when properly informed can planners choose initiatives that will result in successful emissions reductions. Traffic engineers and planners focusing on sustainability can explore tailored traffic engineering data solutions to support targeted studies and low-emission strategies.
Picturing the Future With Big Data
At every turn in the fight against carbon emissions, data is critical for making informed, effective decisions. In transportation, planners must have access to a wide range of emissions-related metrics, such as:
Truck traffic by vehicle class (light-, medium-, and heavy-duty)
As urbanization continues to transform U.S. cities, this data has never been more critical for the decision-making process. Big data providers like StreetLight are helping to fill data gaps that would otherwise prevent planners from understanding their city’s impact on the climate. That’s how the Twin Cities Metropolitan Council was able to share critical emissions data with local governments, equipping them with crucial insights for local planning, rather than generic national numbers.
The Southern Maine Planning and Development Commission took a similar approach, using big data to power urban planning that reduces emissions. In the video below, see how they measured statewide VMT to develop regional mitigation strategies.
Stanford. “Global carbon emissions from fossil fuels reached record high in 2023.” https://sustainability.stanford.edu/news/global-carbon-emissions-fossil-fuels-reached-record-high-2023
United States Environmental Protection Agency. “Fast Facts on Transportation Greenhouse Gas Emissions.” https://www.epa.gov/greenvehicles/fast-facts-transportation-greenhouse-gas-emissions
United Nations. “Generating power.” https://www.un.org/en/climatechange/climate-solutions/cities-pollution
United Nations. “Seven Ways Cities Can Take Climate Action.” https://unfccc.int/news/seven-ways-cities-can-take-climate-action#
Standford. “How much does air pollution cost the U.S.?” https://sustainability.stanford.edu/news/how-much-does-air-pollution-cost-us
Environmental Science and Technology Letters. “Reducing Mortality from Air Pollution in the United States by Targeting Specific Emission Sources.” https://pubs.acs.org/doi/10.1021/acs.estlett.0c00424
American Lung Association. “Who is Most Affected by Outdoor Air Pollution?” https://www.lung.org/clean-air/outdoors/who-is-at-risk
United States Environmental Protection Agency. “Climate Change Indicators: Greenhouse Gases.” https://www.epa.gov/climate-indicators/greenhouse-gases
Intergovernmental Panel on Climate Change. “Climate Change 2022: Impacts, Adaptation and Vulnerability.” https://www.ipcc.ch/report/ar6/wg2/
United Nations. “Your guide to climate action: Transport.” https://www.un.org/en/actnow/transport
ScienceDirect. “The climate change mitigation effects of daily active travel in cities.” https://www.sciencedirect.com/science/article/pii/S1361920921000687
Yale Climate Connections. “Electric vehicles reduce carbon pollution in all U.S. states.” https://yaleclimateconnections.org/2023/09/electric-vehicles-reduce-carbon-pollution-in-all-u-s-states/
National League of Cities. “The Top 5 Ways Cities Are Addressing Climate Change.” https://www.nlc.org/article/2022/04/22/the-top-5-ways-cities-are-addressing-climate-change/
Georgetown Climate Center. “Issue Brief: Estimating the Greenhouse Gas Impact of Federal Infrastructure Investments in the IIJA.” https://www.georgetownclimate.org/articles/federal-infrastructure-investment-analysis.html
See how StreetLight's transportation analytics can help you improve mobility outcomes
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.
The Data Behind How Speed Cameras Curbed Crash Rates on One of Philadelphia’s Most Dangerous Roads
The Data Behind How Speed Cameras Curbed Crash Rates on One of Philadelphia’s Most Dangerous Roads
To fix deadly speeding on one of America’s most dangerous roads, Philadelphia installed speed cameras along eight sections of Roosevelt Blvd. Now, before-and-after analysis by StreetLight reveals how effective the strategy really was, and whether it could save lives in other cities.
Roosevelt Boulevard (US Route 1) in Philadelphia, PA has been dubbed one of America’s most dangerous roads. This twelve-lane highway is host to both local and commuter traffic, with at-grade express and local lanes traveling along its length.
Dozens of crashes resulting in severe injury or death occurred on the boulevard in 2020 alone, many of them involving pedestrians. [1] And because Northeast Philadelphia is home to a number of densely populated disadvantaged communities, the victims this boulevard claims are disproportionately people of color, whose communities have long been bisected by these twelve lanes of fast-moving vehicles.
In 2020, the city took measures to address the boulevard’s high crash rates, installing speed cameras along eight sections of Roosevelt Blvd. To understand how these cameras impacted safety conditions on the corridor, StreetLight used its transportation data platform to analyze vehicle speeds before and after the camera installation, looking at data from before COVID, during the pandemic, and as recently as 2024.
Then we investigated where high vehicle speeds persist on the boulevard, revealing potential locations for the next set of traffic calming interventions.
In this article, we’ll explore:
Roosevelt Boulevard’s speed problem
What Philadelphia is doing to reduce speeding
Whether speed cameras made Roosevelt Blvd safer (and how much)
How cities can choose the right traffic calming measures and evaluate their impact
Roosevelt Boulevard’s Speed Problem
At the heart of Roosevelt Blvd’s high crash rates is a history of dangerous vehicle speeds. Although the posted speed limit for much of the highway is 45 miles per hour, residents have complained that drivers on Roosevelt Blvd routinely exceed this limit. In one extreme case in 2013, four pedestrians, including three children, were struck and killed by two motorists traveling over 40mph above the posted speed limit. [2]
Data from PennDOT corroborates residents’ testimony, indicating that prior to 2020, 55% of crashes on the boulevard were attributed to speeding and aggressive driving.
A number of factors make the boulevard’s speed problem particularly deadly. Surrounding the 12-lane freeway, a growing population of Northeast Philadelphians generate significant pedestrian traffic as they access goods and services from the businesses that call Roosevelt Blvd home. Because many of these residents are from Disadvantaged Communities (DAC), they are also less likely to have access to a car, making them reliant on more vulnerable modes of transportation like walking and biking.
In the image below, StreetLight’s Justice 40 map layer highlights in purple the many Disadvantaged Community census tracts that surround Roosevelt Blvd.
Roosevelt Boulevard (in blue) is flanked by clusters of Disadvantaged Communities (in purple), shown by the StreetLight Insight® Justice 40 map layer.
Meanwhile, the roadway design has limited infrastructure designed to improve pedestrian safety or slow vehicles, such as pedestrian islands, bulb-outs, or signalized crossings, dramatically increasing the risk pedestrians face on the stroad.
Considering that pedestrians are five times more likely to die from crashes when cars are traveling 40 mph vs. 20 mph, according to data from the AAA Foundation, any vehicle exceeding the boulevards’ posted speed limit of 45 is likely to kill any pedestrian it strikes. [3]
Philadelphia’s Plan to Reduce Speeding
Now for the good news: a number of safety improvement projects are already in the works to address high crash rates on Roosevelt Blvd.
The City of Philadelphia has secured $10 million in state grants from PennDOT to be used on curb extensions, realignments to crosswalks, traffic lanes, and turning lanes, upgraded traffic signals, and other projects. Another $2 million will go toward the planning of future road design improvements as part of the city’s Route for Change program. [4]
While some of these improvements will be completed as far out as 2040, speed cameras offered the city a faster way to curb dangerous vehicle speeds in the short term.
In 2020, the City of Philadelphia, along with the Philadelphia Parking Authority, installed speed cameras along eight particularly dangerous stretches of Roosevelt Blvd to automate speed enforcement and ticket offenders.
Did Speed Cameras Make Roosevelt Blvd Safer?
Initial reports from the city have shown positive impacts from the speed cameras, with a 90% reduction in excessive speeding, a 36% drop in car crashes, and 50% fewer traffic deaths in the first seven months. [5]
How did speed cameras achieve such a dramatic effect, and will they continue to positively impact crash rates on the boulevard beyond their initial install? Furthermore, will the tactic be as effective in other cities, or along other roadways in Philadelphia’s high-injury network? Finally, are additional safety improvements needed to achieve the city’s Vision Zero goals for the boulevard?
To investigate these questions, we used StreetLight’s Network Performance tool to look back in time at speed conditions before cameras were installed, track the changes in average speeds (as well as rates of speeding) after cameras were installed, and follow up on where speeds are at now, in 2024, to identify where additional safety improvements may still be critical.
Establishing a Baseline
To understand how speed cameras impacted speeds on Roosevelt Blvd, we need to look back at speed conditions prior to their installation in June 2020. Because StreetLight’s Network Performance tool offers five years of comparable data, we can go all the way back in time to March 2019 to establish our baseline.
This timeframe is particularly useful as a baseline, because it allows us to look at typical speed conditions before the COVID pandemic disrupted traffic patterns across the country (we’ll look at how COVID impacted speeds in the next section).
To establish our baseline, we’ve chosen to analyze a typical Tuesday during the peak morning commute hours (8-9 a.m.). (Notably, this section of Roosevelt Blvd is relatively uncongested so even during peak hours, speeds are not tamped down significantly due to traffic.)
A map of average traffic speeds along Roosevelt Blvd. Higher speeds appear in red, while lower speeds appear in green.
In the map above, we can already see that average speeds exceed the 45 mph speed limit along many segments of the boulevard, and we can see where speeding is at its worst, with segments near Pennypack Park, Northeast Philadelphia Airport, and the Woodhaven Rd (PA-63) interchange standing out.
Speed distribution by hour of day and day of week in March 2019 on the Southbound express lane over Pennypack Creek. A beige line marks the mean speed, while the 85th percentile speed is shown with a golden line.
In the image above, we zoom in on a segment of Roosevelt where multiple fatal crashes have occurred — the Southbound express lane over Pennypack Creek. Looking at speed distribution by hour of day reveals that at 8 a.m. on an average Tuesday, the mean speed on this segment is 51 mph. Meanwhile, the 85th percentile speed (i.e. the speed that 85% of vehicles on the corridor are travelling at or below), which is commonly used to estimate rates of speeding, is 59 mph.
Bearing in mind that the posted speed limit is 45 mph along most of the boulevard, these figures reveal that speeding was indeed a significant issue in 2019. And that was before the COVID road safety crisis.
See how dangerous traffic speeds impact walking and biking in your region
It has now been well established that as roads emptied out during the March 2020 stay-at-home orders and subsequent rise in remote work and social distancing, vehicle speeds increased. Unsurprisingly, deadly crashes also spiked. This phenomenon is likely due to the relationship between road capacity and vehicle speed — as capacity increases, drivers tend to take advantage of the extra space to speed up. (This is also why road diets, with their reduction of lane capacity, are considered an effective safety intervention.)
Roosevelt Boulevard was no exception. Looking at the same deadly segment of roadway above Pennypack Creek, we can see that rates of speeding increased above their already high levels.
Speed distribution by hour of day and day of week in March 2020 on the Southbound express lane over Pennypack Creek.
During the peak a.m. hours, average speeds remain the same compared to 2019 (51 mph), but the 85th percentile speed has increased slightly to 60 mph. We also observe that speeds tend to spike even higher during non-peak hours, especially during the late evening.
To address this crisis, just a few months later, in June 2020, the City of Philadelphia installed speed cameras along eight particularly deadly stretches of Roosevelt.
Slowing Down: How Cameras Curbed Dangerous Speeding
Looking at average and 85th percentile speeds along Roosevelt Blvd in March 2022, our analysis corroborates the city’s initial reports of reduced speeding.
Speed distribution by hour of day and day of week in March 2022 on the Southbound express lane over Pennypack Creek, 21 months after speed cameras were installed.
After over a year of automated speed enforcement from the new cameras, average and 85th percentile speeds on the Southbound express lane over Pennypack Creek dropped significantly. The mean speed of 46 mph nearly matches the 45 mph posted speed limit. Meanwhile, the 85th percentile speed has been reduced to 52 mph – just 1 mph higher than the mean speed two years prior.
Following Up: Did Reduced Speeds Stick?
A look at recent data from March 2024 can help confirm whether the speed reduction observed in 2022 has continued, and where further safety interventions may still be critical to saving lives.
Speed cumulative frequency distribution from 2020 to 2024, highlighting the change in speed profile on the Southbound express lane over Pennypack Creek before and after the installation of speed cameras.
In the graph above, we chart speed distributions from each year analyzed (except 2019, which was identical to 2020 above the 30th percentile). The leftward shift highlights that overall speed continued to drop between 2022 and 2024. As of March 2024, a much larger percentage of vehicles are now traveling at or below the posted speed limit of 45 mph.
So has the boulevard’s speed problem been fixed? While rates of dangerous speeding have significantly dropped — and fatal crash rates along with them, according to city reports — some segments of the corridor may still need further intervention.
Segments of Roosevelt Blvd. with average traffic speed above 40 mph on a typical Tuesday between 8 a.m. and 9 a.m., March 2024.
Using the data trimming tool in StreetLight’s Network Performance product, we can zero in on sections of the boulevard where high-speed traffic still poses significant risk to pedestrians. The map above highlights in red the segments with average vehicle speeds above 40 mph during peak morning hours on an average Tuesday.
Although some of these segments have average vehicle speeds that fall below the 45 mph speed limit, we chose to highlight all segments with average speeds above 40 mph because these speeds fall within the range that is particularly deadly for pedestrians, according to the AAA Foundation.
At least nine highway segments of varying lengths emerge as potential candidates for further safety intervention. As we observed in 2019, segments near Pennypack Park, Northeast Philadelphia Airport, and the Woodhaven Rd (PA-63) interchange are among these high-speed areas.
Insights like these could help city officials determine where to prioritize state grant funds slated for additional traffic calming measures along the boulevard.
Spot Speeds on Roosevelt Boulevard
While the bulk of this analysis examines segment speeds, which are derived from a vehicle’s travel time from one end of a roadway segment to another (and the distance between those points), it can also be useful to examine spot speeds at specific locations along a corridor when evaluating potential safety improvements and the success of past projects.
Spot speeds measure a vehicle’s speed at a specific point in time and space, rather than the average speed across a given segment. This means spot speeds are particularly useful when analyzing safety or congestion on smaller roadway segments, such as a single intersection. In our case, they can also help shed light on exactly where drivers slow down and speed up, revealing whether and how quickly drivers speed back up after they’ve passed a speed camera.
In the data viz below, 15 spot speeds taken on a typical Tuesday between 8 and 9 a.m. in March 2024 show vehicles slow down after passing Pennypack Creek as they approach a speed camera located near Strahle Street. Drivers then speed up again as they approach Solly Ave, slowing once more as they approach an intersection with pedestrian crosswalks at Rhawn Street. These granular insights can help cities like Philadelphia determine the most effective safety measures to further the benefits of speed cameras.
Colored dots show spot speeds along Roosevelt Blvd. near Pennypack Creek on a typical Tuesday between 8 a.m. and 9 a.m., March 2024.
More About StreetLight’s Network Performance Tool
StreetLight’s Network Performance tool is ideal for before-and-after analyses like this. It offers five years of data comparability so cities can look back in time to understand how roadway conditions have changed over time, including traffic patterns from before COVID, which are often sought out as a baseline to understand “typical” past conditions. They can also analyze the impact of policy interventions to show the public the efficacy of their work.
Since many roadways lack permanent traffic counters (or only recently had counters installed), this ability to access historical traffic data for any road unlocks before-and-after analyses that would otherwise be impossible.
As we’ve demonstrated in our analysis above, agencies can use this Network Performance tool to proactively identify locations with a trend of excessive speeding, particularly where it overlaps with high crash rates, pedestrian/bicycle activity, or Justice40 communities.
With the data trimming option shown in the section above, agencies can easily pinpoint problematic road segments instead of relying on anecdotal observations about excessive speeding, or worse, waiting for the next crash to identify an unsafe traffic pattern. Likewise, this tool offers agencies the ability to monitor the impacts of changes in land use (e.g., new development), infrastructure (e.g. lane additions), traveler behaviors (e.g. work-from-home patterns due to COVID), traffic calming measures (e.g. speed limit reductions or speed cameras), and more.
The ability to analyze both segments speeds and spot speeds also offers added granularity that can be useful in understanding driver behaviors and diagnosing dangerous locations along a roadway.
Delaware Valley Regional Planning Commission. Crash Statistics for the DVRPC Region. https://www.dvrpc.org/webmaps/crash-data/
CBS News. “Philadelphia’s Roosevelt Blvd. Among most dangerous roads in US” July 10, 2023. https://www.cbsnews.com/philadelphia/video/philadelphias-roosevelt-blvd-among-most-dangerous-roads-in-us/
AAA Foundation for Traffic Safety. “Impact Speed and a Pedestrian’s Risk of Severe Injury or Death.” September 2011.
Michaela Althouse. Philly Voice. “Philadelphia gets $19.3 million for road safety projects from PennDOT, most directed to Roosevelt Boulevard work.” February 3, 2024. https://www.phillyvoice.com/roosevelt-boulevard-traffic-safety-projects-philadelphia-grants-penndot/
Philadelphia Parking Authority. Roosevelt Boulevard Automated Speed Camera Annual Report. April 2023. https://philapark.org/wp-content/uploads/2023-Speed-Camera-Report-Final-32023.pdf
Investigate local traffic trends with a free trial of StreetLight InSight®
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.
What is AADT, why does it matter, and how does big data make it more powerful?
What is AADT, why does it matter, and how does big data make it more powerful?
As agencies grapple with budget and staff limitations, big data analytics enable officials to overcome gaps in Annual Average Daily Traffic (AADT) data for local streets and low-volume roads. But first, what is AADT, and how does it inform transportation decisions?
In recent years, infrastructure improvement has become a hot topic in the US.
At the center of that interest are our streets, roads, and highways. Road conditions are a key factor in an area’s quality of life, economic dynamism, as well as access to schools, jobs, and healthcare.
Jurisdictions across the US are gearing up to improve their road networks, in part thanks to the federal Bipartisan Infrastructure Law (BIL), also referred to as the Infrastructure Investment and Jobs Act (IIJA), which makes $110 billion available for these improvements.
Behind the scenes, there’s one transport metric that is fundamental to nearly every federal funding request or routine budgeting at the state or local level: Average Annual Daily Traffic (AADT). (Learn how to access Average Annual Daily Traffic metrics programmatically using StreetLight’s Traffic Data API.)
Annual Average Daily Traffic (AADT) is the transportation industry’s most essential metric for analyzing and forecasting traffic volume. Among other things, it’s used for the planning and design of infrastructure, tracking traffic congestion, estimating road safety, and as an empirical measure to help allocate highway funds.
In its simplest form, AADT takes in all vehicle trips on a segment of road or highway during a yearlong interval, in both directions, and then divides the total by 365 days to arrive at the average number of daily trips.
In addition to infrastructure and transport planning, AADT data is applied in many other contexts as a way to measure traffic flow and allow for “apples-to-apples” comparisons of traffic volume. For example:
Lawyers and law enforcement officials use the metric in accident cases and investigations
Lawmakers use AADT to inform budgeting and prioritization of transport budgets and projects
But AADT is also a simple measure, which flattens away seasonal and weekday variations in traffic patterns. Nonetheless, AADT remains the most widely-referenced benchmark for how busy a road or street is.
AADT vs. ADT
There are two main types of traffic measurement: Annual Average Daily Traffic (AADT) and Average Daily Traffic (ADT).
These measures are starkly different in how they are calculated and applied. They are often confused in casual discussions so it’s important to understand the differences.
As described above, AADT is the total volume of vehicle travel on a road for an entire year, divided by 365.
ADT is the average number of vehicles traveling through a location during a period shorter than a year. For example, it may be applied to a season, or a selected month or week, a short span of days, or a specific day in the year.
AADT is generally used to measure long-term trends or changes in travel demand, while ADT is more useful for short-term planning and operations.
For example, if a city wants to know how many people use a particular bridge to estimate wear-and-tear and traffic loads, it would use AADT. But if that same city needs to know how many cars will cross the bridge during a summer weekday to plan construction, it would use ADT calculated from a sample taken in the target interval.
Both measures have their advantages and disadvantages.
AADT can obscure seasonal variation (e.g., fewer people travel in winter), special events (e.g., increased travel for holidays or road closures within the measurement period), and day-to-day variation in demand (e.g., less travel on weekends). This can sometimes make it difficult to compare year-over-year changes or identify important micro-trends.
ADT can pick up these kinds of fluctuations, but they will not reflect overall demand on a road since by definition they only consider shorter periods. On the other hand, they have a limited lens: they will not reflect in any variations occurring outside of the measurement period.
As discussed below, AADT data is relatively difficult and expensive to collect since it requires real-world data spanning an entire year. Even when using calculation methods that don’t require 365 days of data, the need for accurate and continuous data is still relatively burdensome.
ADT is more forgiving from a measurement standpoint since by definition it requires the counting of traffic during shorter intervals.
How to calculate AADT
To calculate Annual Average Daily Traffic (AADT) in its simplest form as described above, analysts must know total traffic volume on the target road segment for every day in a given year.
This baseline method isn’t simple or cheap to implement since by definition it requires permanent devices known as counters or ATRs (automatic traffic recorders) detecting passing vehicles and collecting complete trips data for 365 continuous days in a year. Even missing a few hours of traffic means the calculation can be thrown off. Not to mention the recorders are not easy or inexpensive to install and maintain. During the COVID-19 lockdown, agencies saw their ability to collect counter data hamstrung by lockdown orders that kept workers off the road.
Even when permanent counters are in place and putting out continuous AADT traffic data, sometimes special events such as roadwork or adverse weather can distort averages with outlier days of abnormally low or high trip counts.
Finally, and most commonly, there are simply too many road segments in any jurisdiction to allow for comprehensive AADT data from permanent counters.
In the video below, Keith Nichols explains why Hampton Roads TPO commonly encounters data gaps with traditional AADT data collection methods, and how the agency supplements traditional methods for long-range transportation planning.
Traditional methods of closing AADT data gaps
Statistical methods, complemented with temporary data collection, are commonly deployed to address common data-collection issues. When officials turn to these methods, they do so knowing they are sacrificing accuracy for savings.
It’s worth understanding how these methods work together, and some of the tradeoffs.
Short-term expansion
One industry-standard method for arriving at Annual Average Daily Traffic (AADT) in the absence of permanent counters is known as “short-term expansion.”
In this method, a road section’s traffic is calculated on the basis of a temporary counter collecting two days or more of data. That incomplete short-term data is then “expanded,” or scaled up, to calculate AADT. To do this, analysts derive scaling “factors” from a nearby permanent traffic counter that has a year’s worth of data.
Ideally, that permanent counter used as a reference has same-year data. But it’s not uncommon for transport analysts to be forced to rely on permanent counter data from past years when calculating AADT using this method.
Obviously, even when the short-term expansion model bakes in some math, this tactic relies on the differences between the target road’s short-term traffic data versus the same-day measurements collected by the nearby permanent counter on a different road.
If these differences are not consistent across the year, i.e. if the short-term data was not taken on representative days, AADT accuracy will be compromised.
In the instances where permanent counters are in place but there are small gaps in the annual data or road closures and other outlier events that may throw off the averages, a separate established method is to limit the number of days for which complete datasets are required.
The AASHTO method
In one industry-recognized approach, officials collect total traffic volume on seven separate days in each month that correspond to the different days of the week. This method leaves planners with 84 days of data to work with that nonetheless will account for variations in traffic across different weekdays and on weekends.
Then, they take an average for each day of the week sampled across the year, giving them seven averages, and then they take the average of those averages for an AADT.
The American Association of State Highway Transportation Officials (AASHTO) has promoted this technique, known as an “average of averages” method.
Other methods
Many other estimation methods can be used depending on what data and counters are available and affordable. In fact, the proliferation of methods adds to the complexity faced by transport planners as they consider approaches for data collection and AADT calculation.
In fact, one in-depth review of the relevant academic literature on AADT estimation identified 30 separate methods just for estimating AADT on low-volume roads.
Adding to the difficulty, these techniques were hardly one-size-fits-all.
“Some AADT estimation techniques are only applicable in specific locations,” write the authors, Edmund Baffoe-Twum and Eric Asa of the West Virginia University Institute of Technology, along with Bright Awuku from North Dakota State University. “Others require significant data to provide accurate estimates. Several processes to adjust models for a location may be needed for other locations.”
Traditional methods vs. traffic analytics
Arguably the biggest change for Annual Average Daily Traffic (AADT) in recent years is the availability of instant up-to-date AADT estimates right from a computer through traffic-analytics providers.
On-demand traffic-analytics platforms reduce the need for expensive and sometimes hazardous fieldwork and are able to fill data gaps whenever they arise.
As a result, jurisdictions have more flexibility in the extent to which they rely on permanent and temporary counters for AADT metrics.
For example, recently StreetLight helped fill gaps in AADT data by the Indian Nations Council of Governments in Tulsa, Oklahoma. Due to budget issues, many jurisdictions in the area had stopped reporting traffic counts to INCOG, a metropolitan planning organization or MPO. In minutes, StreetLight was able to generate traffic counts for all of the untracked road segments.
In the video below, we explore other ways agencies commonly use on-demand traffic analytics platforms to leverage AADT metrics, such as developing crash rates and understanding the traffic impact of road or lane closures.
How do traffic-analytics platforms come up with their AADT measurements?
Typically, traffic analytics rely on connected devices and Internet of Things data, and then layer in parcel data and road-network data for a complete picture. With this data, it’s possible to create analytics that model vehicle trips on a stretch of road in the absence of temporary or permanent counters.
The real technical challenge for deriving AADT from traffic analytics is not just in collecting and organizing the large volume of location data, but in the next steps:
Algorithms are needed to match this raw data to vehicle trips
The dataset, for greater accuracy, is enhanced with additional sources of data such as US Census Data or street-map data to account for changes in demographics and road networks
The resulting AADT model must be tweaked for greater accuracy by testing results against real-world “ground truth” data, which should encompass different road and vehicle types, e.g. heavy trucks
In the case of StreetLight, which provides AADT metrics for 4.5 million miles of roadway in the US and Canada, all these steps were important and detailed in the whitepaper, “AADT 2023: U.S. Methodology and Validation.”
By comparing their own AADT metrics to AADT produced by thousands of permanent counters nationwide, StreetLight was able to determine that their AADT figures fall within a 98% prediction interval for all road types.
Challenges in measuring AADT: local and low-volume roads
AADT measurement is increasingly being shaped by many jurisdictions’ need for more granular and complete coverage of road systems.
What’s driving this demand? The answer is a set of interrelated traffic, demographic, and environmental concerns that are only growing stronger with time.
First, local streets are increasingly seeing overflow traffic from overburdened highways and multi-lane roads.
“Estimating AADT on local streets becomes a necessity as local street traffic continues to grow and the capacity of arterial roads becomes insufficient,” write Peng Chen, Songhua Hu, Qing Shen, Hangfei Lin, and Chie Xie. They are the authors of a 2019 paper on AADT measurements in the Seattle area, published in the Transportation Research Record.
Second, jurisdictions are also newly anxious to track traffic increases on low-volume roads in rural and semi-rural areas. Many of these areas have seen a major influx of short- and long-term visitors and new residents arrive over the last two years.
A 2022 analysis by StreetLight showed how this trend had impacted the resort town of Jackson Hole, Wyoming. The analysis showed that AADT on a section of unpaved road —an access point to Grand Teton National Park — had already significantly surpassed 2019 levels in 2021, even after dipping dramatically during the COVID pandemic.
AADT counts for Moose-Wilson Road from StreetLight suggest 2021 traffic volume had already exceeded 2019.
Thirdly, environmental and road-safety concerns are also behind the need for more comprehensive AADT data. Since a significant proportion, if not a majority, of vehicle miles in a state are driven on these roads, it’s impossible to form a complete picture of emissions or accident trends without it.
Despite the demand, coverage of low-volume and local streets poses a formidable challenge for traditional AADT calculation.
As we’ve seen, it is cost-prohibitive to deploy permanent counters widely on local streets or low-volume roads. Not to mention, rural roads are far-flung and cover many miles of sometimes difficult terrain. Local roads in urban areas are dense and highly varied in traffic patterns, which would mean putting counting stations on virtually every corner.
Many jurisdictions, in the cases where they have the budget to take the measurements at all, turn to temporary counts and estimation methods to measure AADT on these segments.
For these reasons, traffic analytics–based AADT metrics are a cost-effective and simple solution for filling data gaps on local and low-volume roads.
For example, StreetLight’s AADT metrics include urban and rural roads — even unpaved roads, as seen in the case study from Jackson Hole. Analyses covering hundreds of low-volume road segments can be run in minutes.
Annual Average Daily Traffic (AADT) and technology
Traffic-analytics platforms relying on big data approaches are only the latest tech innovations to transform how Annual Average Daily Traffic (AADT) is collected and calculated.
In the 1930s, AADT was based solely on manual counts, which required considerable manpower and intensive fieldwork, according to David Albright in a 1991 article on the history of AADT measurement. Counting devices only began to be used in the 1940s, and became widespread only after a couple of decades, with methods continuing to evolve in the years since.
More recently, computers and algorithms have helped run some of the sophisticated statistical models used by transport engineers and planners for AADT estimation. As discussed, StreetLight itself uses advanced software algorithms to process data, tie it to vehicle trips, and enhance it with U.S. Census and OpenStreetMap data.
While conceptually AADT has remained the same metric over all this time, and surprisingly resilient as a keystone metric in transport planning, technology has completely transformed data collection, calculation, and estimation methods. It’s a good bet that technology, and specifically big data and software-driven algorithms, will continue to drive innovation around AADT in coming years.
AADT 2025 FAQs
Each spring, StreetLight generates early AADT estimates to reflect annual traffic volumes from the previous year, helping agencies obtain accurate, defensible, and timely traffic counts for faster reporting, planning, and analysis without the need to deploy staff or sensors. Later each year, we update these estimates in our “Final Release,” which incorporates additional data from permanent counters to fine-tune AADT results.
Each spring, as we announce our new AADT, industry professionals come to us with a lot of savvy questions about our AADT methodology, reliability, coverage, and more.
Spring 2026 marks our ninth consecutive year delivering industry-validated U.S. AADT metrics for nearly every roadway, so we’ve put together a list of some of your most frequently asked questions from across the years to satisfy your curiosity about all things AADT, from how we measure it to how you can use it.
If you have a question we haven’t answered below or want to explore getting early access to StreetLight’s AADT 2025 estimates, reach out to our team here.
Get early access to validated AADT 2025 estimates for your roads
StreetLight offers an Initial Release of AADT estimates in the spring of each year to help state DOTs meet reporting deadlines. Early Access AADT 2025 counts will be available from StreetLight in March 2026.
2. Can I compare the AADT counts year over year?
Yes, StreetLight’s AADT counts are rigorously validated to ensure reliable, high accuracy metrics that are comparable year-over-year, allowing agencies to report on how traffic is changing on their roads and perform before-and-after studies.
With StreetLight’s AADT metrics, you can analyze trends over time for seven years (2019 – 2025) of history with easily comparable historical AADT estimates.
3. How accurate is it? How does StreetLight validate the AADT?
Our data science team publishes an annual white paper highlighting the robust validation process for the StreetLight AADT metrics – see the new 2025 white paper here. StreetLight’s AADT 2025 estimates strongly correlate with ground-truth AADT counts, with a best-fit line’s r-squared of 0.98, which means that StreetLight’s 2025 AADT estimates align very closely with real-world permanent counter traffic counts, demonstrating an exceptionally high level of accuracy).
In addition to validating against permanent counters, StreetLight’s AADT counts meet the industry standard FHWA benchmarks demonstrating high accuracy and precision across all road sizes.
Cross-validation results for StreetLight AADT 2025 by road size, shaded to compare with short-term count expansion errors (new FHWA target benchmarks), indicate that StreetLight’s AADT model outperforms the new FHWA benchmarks (12 out of 12 categories). Specifically, StreetLight performed nearly two percentage points better than the target MAPE on mid-and high-volume roads, and at target on the lowest volume roads. Bias also outperforms the target by nearly one percent on low-and mid-volume roads and meets the target on the highest volume roads. This means you can expect model StreetLight AADT estimates to be, on average, closer to actual counter AADT volumes than 48-hour temporary traffic volume studies.
4. What is the coverage? Do you have counts for all road types?
Among the key benefits to using StreetLight’s AADT metric is that it covers all road types for all geographies across the U.S. This means agencies of all sizes can get regional and network-wide views of annual average daily traffic volumes.
StreetLight AADT covers nearly every road in the U.S., providing traffic estimates for all road segment types, including highways, low-volume, and recently developed roads.
For residential and low-volume road types that are typically more challenging for agencies to get counts for, we have improved coverage across all years by including inferred volumes in low-sample areas, which are verified to produce reasonable sample estimations and time trends. You can learn more about this methodology in the StreetLight Volume Methodology white paper.
5. How can I use StreetLight AADT for MIRE or HPMS reporting?
When it comes to the Model Inventory of Roadway Elements (MIRE), the FHWA’s MIRE Data Collection Handbook allows AADT counts to be collected through third-party sources such as StreetLight (see p. 138). StreetLight’s AADT allows you to boost your existing roadway inventory with fundamental data elements (FDE) for nearly all public roads, including…
AADT for each road segment and intersecting road — (Vehicle per day)
AADT year
AADT Annual Escalation Percentage
Ramp AADT
Year of Ramp AADT
Approach AADT
…and many more
StreetLight can also help with Trip Speeds (85th percentile and mean), Turning Movement Counts, hourly traffic volumes, interchange entering volumes, peak hour directional factor, and approach directional flow.
Likewise, StreetLight’s AADT provides valuable input for HPMS reporting, and multiple state DOTs use StreetLight for HPMS reporting each year.
You can review the federal guidance for Obtaining AADT Estimates from Non-Traditional Sources for more details. This guidance also includes helpful checklists for evaluating big data sources and provides updated accuracy and precision benchmarks that we include in our own validations and white papers.
6. Can I get more granular traffic count volumes via StreetLight such as daily or monthly?
StreetLight’s AADT metrics are updated annually with a corresponding white paper for folks looking for an easy, consistent way to get average annual daily traffic counts year-over-year across all road sizes and types, which is especially helpful for federal reporting.
When you need to drill down into historical vehicle volumes for specific time periods such as monthly, daily, or hourly traffic counts, other types of analyses in StreetLight InSight® can help. For example, you can access granular intersection turning movement counts at 15-minute granularity as well as monthly/daily/hourly volumes on any road segment.
7. How can I get AADT for hundreds of specific locations? Can I upload my own LRS/zones?
There are many ways to get AADT counts at scale through StreetLight, including…
Leveraging the StreetLight InSight® API
Using StreetLight’s Zone Library to select multiple segments
Uploading your own shapefiles to the platform
Working with our Services team to easily get AADT aligned to your Linear Referencing System (LRS)/base road network for map matching or have them deliver files with AADT counts at scale, along with any other custom specifications your agency may have
8. What is the value of using Big Data for AADT counts?
Other typical data collection methods like temporary counts and permanent sensors can be expensive and offer limited temporal and geographic coverage. That’s why many agencies are now using Big Data sources to…
Get validated traffic counts that meet industry accuracy targets on all road sizes
Analyze recent and historical AADT traffic counts that can be compared year-over-year
Go back in time to capture historical insights for any roadway, including newly developed roads and rural roads
Get counts on your desktop without having to go out in the field
9. What do people use StreetLight’s AADT metrics for?
StreetLight’s AADT metrics can be used for virtually any scenario where you might use AADT collected via traditional methods like sensors, from analyzing traffic impact to evaluating road safety. Other common use cases include:
Federal Reporting: State DOTs can use StreetLight AADT to help streamline federal reporting and explain changes in AADT when they are noticeable compared to the previous year.
Project Prioritization: Agencies can use StreetLight to measure the latest AADT on every road in their jurisdiction to prioritize funding for programs such as pavement improvements.
Grants & Funding: Agencies often need to report on the last 5 years of AADT on select roadways where grants were approved to meet the performance management and reporting requirements from the grant.
Ready to dive deeper and join the conversation?
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.
How Advanced Traffic Counts are Powering Better Business Decisions
How Advanced Traffic Counts are Powering Better Business Decisions
Understanding traffic patterns is critical when choosing a store location, designing automotive products, or analyzing property values. Now, businesses can get the most up-to-date traffic counts on 2.5x more roads to drive more profitable decisions.
For many businesses, transportation intelligence is critical to making the right decisions. The number of vehicles and pedestrians on a given road — and how they move throughout a region — can dramatically impact how many visits a store gets, where drivers need to fuel up, or if EVs need to charge.
But historically, commercial decisionmakers have had to rely on incomplete and outdated traffic counts for information on where and how potential customers drive.
Now, StreetLight offers Advanced Traffic Counts to inform real estate decisions and products for professionals across industries like:
Commercial real estate
Retail and restaurants
Software
Electric vehicles
New mobility
These counts are updated frequently and cover millions of road segments across the U.S. and Canada, so you can make confident decisions based on the most comprehensive, up-to-date information on travel patterns.
StreetLight Advanced Traffic Counts is designed specifically for the commercial sector, to understand how potential customers move so you can choose the right street corner for a new store, select EV charger locations based on nearby traffic patterns, or develop new products and services based on real customer travel behaviors. Paired with location intelligence software, this allows for deeper context.
Here’s how it works.
StreetLight Advanced Traffic Counts offer pre-processed traffic volumes for over 25 million road segments, totaling over five million miles in the U.S. and Canada including motorways and trunk roads, arterials, and on/off ramps for comprehensive coverage. But it doesn’t end with traffic volumes. This data can be further contextualized with additional details like trip characteristics and historical demographics so you can make much more nuanced business decisions.
StreetLight Advanced Traffic Counts offer pre-processed traffic volumes for over 25 million road segments, totaling over five million miles in the U.S. and Canada including motorways and trunk roads, arterials, on/off ramps, and residential streets for comprehensive coverage.
A visualization of traffic counts in the broader Chicago metropolitan area. StreetLight’s extensive coverage provides traffic counts for millions of road segments, enabling more granular location intelligence to power the most profitable business decisions.
This means that as you begin to identify the next corner for your coffee shop, convenience store, or electric vehicle (EV) charger location, you can take into consideration factors like vehicle traffic, trip purpose (e.g. home-to-office vs. non-commute trips), and the overall demographics (e.g. income, education, family status, and more) of travelers passing by your potential location.
Likewise, these same factors can inform portfolio management for existing commercial real estate locations, diagnosing why some locations perform better than others, and where certain locations should be closed, where open hours should be extended or shortened, or where downsizing or expansion would help maximize overall revenue.
Market research firms and consultancies also benefit from these same insights when advising clients on commercial real estate decisions.
A zoomed-in view of Chicago traffic counts highlights roadways with the most trips (seen in dark red) and the least trips (in yellow).
How StreetLight’s Traffic Counts Support Better Site Selection and Operations
Because of the extensive coverage of our traffic counts, and the ability to filter counts by time of day and day of week in the relevant month or year, retailers, real estate professionals, investors, and other customers can now more easily identify promising store locations along nearly any roadway in the U.S. or Canada.
Importantly, businesses that rely on foot traffic (such as retail and restaurants) and usefoot traffic software can also view historical pedestrian traffic counts to understand where high foot traffic will translate into more sales, while businesses that rarely benefit from foot traffic (such as car washes) can narrow their focus to vehicle traffic counts exclusively.
Importantly, businesses that rely on foot traffic (such as retail and restaurants)…can also view historical pedestrian traffic counts to understand where high foot traffic will translate into more sales, while businesses that rarely benefit from foot traffic (such as car washes) can narrow their focus to vehicle traffic counts exclusively.
These same insights can also be used to forecast sales at new and existing stores. Portfolio managers can now understand where traffic is most likely to drive store visits and sales. Using traffic counts by time of day and day of week, they can also determine if store hours or staff operations should be shifted to capture demand when it is highest.
To integrate advanced count strategies into operations, traffic engineering data solutions can provide tailored data services to support your goals.
Trip and Traveler Attributes Help Determine Where Demand is High
Traffic counts are just the tip of the iceberg when it comes to site selection, research and development, and more. That’s why StreetLight Advanced Traffic Counts and site selection software also include trip speeds, trip distance, and historical trip purposes and traveler demographics to further inform important decisions impacting your business.
Visualization of traffic volume with trip and traveler characteristics for two locations
For example, a commercial real estate professional evaluating potential locations for a new coffee shop could zero in on road segments that morning commuters take on their way to the office. Similarly, someone looking to open up a new location for a budget-friendly grocery store chain could pinpoint road segments that are frequently used by travelers with lower household incomes.
Likewise, adding the context of trip characteristics can further inform commercial real estate decisions. For example, traffic volume may not tell the full story for brands who rely on drivers traveling slowly enough to read their signage and turn into their location.
Luckily, with StreetLight Advanced Traffic Counts, these customers can take trip characteristics like speed into consideration to ensure the traffic at the site they select isn’t speeding by too quickly to bring in business.
Likewise, trip characteristics like direction of travel can inform which street corner or side of the road is most advantageous for a new store.
Ensuring Reliable Data for Confident Business Decisions
We’ve already discussed how StreetLight Advanced Traffic Counts allow commercial customers to access recent and historical data for a full-picture view of mobility patterns impacting their business. But how reliable are the metrics we provide?
Every month, we ingest, index, and process vast amounts of location data from connected devices and the Internet of Things, then add 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.
This data is then delivered in bulk through either a data file (such as a CSV) or via API, to integrate seamlessly into your existing data analysis platforms. For automated, large-scale traffic count integration, explore StreetLight’s Traffic Data API.
To understand how your customers move and get more information on the travel patterns impacting your business, click the banner below to get started.
New truck data reveals how port traffic is changing
New truck data reveals how port traffic is changing
In the first four months of the year,data on heavy-duty truck traffic at some of the biggest ports in North America indicatea sector in transition, with divergingtrendsby geography and sector. New truck traffic data from StreetLightenables the private sector across diverse industries, including retail site selection, vehicle electrification, ports and distribution hub planning, and insurance risk assessors, as well as public sector agencies,to keep pace with these trends as they happen.
Heavy-duty truck traffic between January through April at some of North America’s largest ports reveals a supply chain and logistics system in transition, with increases in truck activity year-over-year at ports in Georgia and Texas, versus contraction or mixed results at ports in Los Angeles and Vancouver, British Columbia.
The analysis comes from StreetLight’s newest truck product, which enables private sector businesses to stay up to date on the most recent changes in supply and logistics ground travel patterns and adjust accordingly.
The data indicates that it has been a bumpy few months for truck traffic around the major North American ports. Heavy-duty truck stops and starts around the boundaries of Georgia’s port region saw an initial contraction in activity before bouncing back to growth in February. The port at Vancouver, Canada’s largest facility, saw a similar but more pronounced trend, a dramatic decline in truck activity growth through March before climbing back to the positive in April.
The port of Los Angeles on the West Coast stands out as the facility where truck traffic has contracted throughout the entire first third of the year, with double-digit declines in heavy-duty truck stops and starts for the past six weeks, compared to the year prior.
However, diving deeper into the data we can see it is a mixed bag by industry, with some sectors remaining strong at the Port of LA, while others dip.
Among the five largest industries for truck activity at the Port of LA, one of the largest declines is in manufacturing, down 40–50% year-over-year, according to StreetLight’s data. This downturn aligns with other third-party indicators, such as a drop in the ISM Manufacturing Index and contraction in industrial production in Q1 2025.
That said, manufacturing only accounts for about 7% of trucking activity at the port, whereas transportation and warehouse, at 46% of truck stop and starts, is by far the largest slice of trucking activity at the port. This sector, alongside wholesale trade, has seen trucking activity remain positive around the port.
Of course, there are many varied signals at every port. While StreetLight finds a dip in heavy-duty truck activity around the Port of LA, alongside the drop in the manufacturing index, total cargo volumes increased in the first three months of the year, according to Freight Waves. This points to the complexity of factors impacting ports, and the importance for businesses interconnected to the supply chain and logistics industry to keep pace with fast-changing trends.
StreetLight’s data can help shine a light on the most recent shifts in trucking activity coming out of these ports and throughout the U.S. and Canada. Clients looking to dive deeper into these and segment-level trucking activity can access nuanced metrics and travel pattern data to better understand shifts in the flow of ground transport that affect their industry.
How New Truck Data Can Help Businesses Adjust Dynamically to Changing Conditions
As the trucking industry faces a changing landscape, private sector companies are also grappling with a persistent challenge: a lack of detailed, reliable, and up-to-date truck data across the U.S. and Canada.
Whether it’s understanding where commercial trucks are traveling to optimize sites for truck fueling or service stations or estimating exposure for insurance risk modeling, many businesses require robust, granular insights into truck activity—especially in an era marked by electrification, regulatory shifts, and evolving freight patterns.
But much of this data is either too outdated, has gaps in coverage, lacks detailed insights such as industry and route type, or is simply not available in a useful format for private organizations.
StreetLight has a suite of truck data products tailored specifically for the private sector to deliver unmatched commercial truck insights through a range of tools designed to answer real business questions—fast.
To predict customer demand at potential new truck stops, fuel locations, convenience stores, and more, understanding nearby truck activity is key. StreetLight allows you to:
Compare truck activity and volumes between potential sites
Compare all vehicle activity vs. truck activity to further contextualize demand
Monitor truck activity around current sites in your real estate portfolio
Monitor truck activity around competitors’ sites
Analyze truck activity by fuel type, weight class, route type (long-haul vs. Local) and more to understand demand for specific fuels or truck infrastructure
Data for Truck Fleet Electrification
StreetLight’s truck data can also help you effectively electrify truck fleets and plan charging infrastructure that supports their use.
Information on truck trip lengths, high-volume routes, dwell times, and more can help you anticipate charging needs, choose locations for charging stations, and plan routes efficiently.
Truck Data for Market Research and Product Development
The ability to segment nationwide truck activity data by weight class, trip types, and industry segments supports detailed market research and product development efforts, helping you go beyond overall truck activity to understand what your customers need.
For example, you might look at nationwide truck activity to forecast future truck market demand based on weight class, industry, and trip type. Meanwhile, the same metrics can also be used to inform product development roadmaps or comply with regulations like California’s Advanced Clean Trucks.
Understanding Insurance Risk and Exposure
Want to understand how truck activity impacts risks to health or property in different locations? StreetLight’s truck data can help you analyze truck activity along specific roads or within an entire region to inform risk assessment. Plus, you can compare truck activity to overall vehicle activity for further context.
Truck Data for Port and Distribution Hub Planning
The analysis above illustrates a few useful ways to analyze truck activity around ports and hubs to understand industry trends. Understanding the fast-changing trends in port and distribution hub activity, as well as how different ports and hubs compare to one another, and which industries may be most impacted, can help you optimize logistics and anticipate supply chain fluctuations.
Freight Corridor and Bottleneck Insights to Reduce Delays and Improve Trucking Infrastructure
While some decisions require nationwide trucking insights (which our data also supports), others may require a closer look at specific freight corridors. Understanding where freight bottlenecks are happening and how goods flow along key corridors helps you avoid delivery delays and understand where infrastructure improvements may be needed.
Turning Truck Metrics into Actionable Insights at Any Scale
StreetLight offers a variety of data delivery methods to fit the scale of your questions and your team’s level of data science expertise.
Data can be delivered pre-processed for the entire U.S. or county for teams needing data at scale in a digestible format to fit into any workflow. This includes truck volume with class breakdown and VMT.
For companies that need deeper insights, detailed truck activity segmented by route type, industry, and trip attributes (e.g., long-haul vs. local) is available. Users can access key metrics like:
Congestion
Speed
Travel Time Reliability
Industry (e.g. manufacturing, construction, retail)
Intra- vs. Inter-State/Province Travel
Long-Haul vs. Local Travel
Additionally, for businesses looking to understand multi-trip analytics, StreetLight’s Services team provides tailored analytics such as:
Dwell time and stop counts at truck stops
Fuel type breakdowns
Vehicle type classification
Truck tours
Ensuring Reliable Truck Data for Confident Business Decisions
Knowing your decisions are based on recent and reliable information is crucial, so StreetLight always validates metrics rigorously before they ever make it into the hands of our users. To learn more about how StreetLight’s trucking data is collected, processed, and validated, download our Truck Volume Methodology and Validation white paper.
If you’re part of the private sector and looking to make smarter decisions about site selection, risk modeling, or infrastructure planning, reach out to understand how StreetLight’s truck data solutions can give you a competitive advantage.
If you are looking for more info about public sector truck data, check out freight planning solutions here.
Smart cities use innovative technologies to improve operations, expand access to goods and services, and get things done more efficiently. At the center of it all, transportation data is changing how cities make decisions that impact how people move.
Today, nearly everything has become “smart,” from phones to fridges, doorbells, and cars. And cities are no exception. Across the globe, cities large and small are adopting new technologies to improve quality of life, automate essential services, and integrate with the digital world.
So how exactly are “smart city” technologies changing how we live? And what role does transportation data play in making our cities “smarter”?
In this article, we’ll discuss:
What is a smart city?
Smart city technologies in use today
How smart cities use transportation data
Real-world examples of smart city transportation projects
What Is a Smart City?
A smart city is a city that uses data to optimize operations, planning, and governance. Data collected from residents and visitors, electronic devices and systems, and the broader Internet of Things is analyzed to understand patterns, monitor how things are going, communicate with constituents, and more.
If this all sounds incredibly broad, it is. Most cities today are smart cities, because data collection and analysis have become ingrained in just about everything we do.
Still, the extent and sophistication of data usage varies greatly from city to city. Below, we’ll explore some of the common ways smart cities are using this data.
Ride hailing apps for taxis, microtransit, and rideshare services are common in today’s smart cities.
Smart City Technologies
There are many types of smart cities technologies in use today. Some common examples include:
Real-Time Transit Tracking – GPS data from buses, subway cars, etc. are used to calculate wait times for public transit, communicated via mobile apps or station signage.
Energy & Utilities Optimization – usage data for electric grids, water, and more can be monitored and in some cases automatically adjusted to prevent service disruptions, detect leaks, anticipate the need for infrastructure improvements, or aid conservation efforts.
Smart Lighting – light detection technology can be used to automatically turn on overhead lights for roadways, parking lots, and more during poor lighting conditions (not just at nighttime).
Smart Traffic Signals – smart traffic lights use real-time data on the volume and speeds of vehicles approaching an intersection to automatically adjust the timing of signals to reduce idling time, improve traffic flow, or prevent unsafe conditions.
Air Quality Monitoring – sensors may be deployed throughout the city to monitor air quality, detect potential sources of pollution, communicate current conditions with the public, and inform air quality improvement efforts.
These and other technologies are becoming more and more common in cities across the globe. But one of the most frequently used forms of smart city technology is transportation intelligence. Below, we’ll discuss some of the key ways smart cities are using transportation data to improve mobility, air quality, climate impact, and more.
See how data can help you fix traffic jams, speeding, and more
Data on how people and vehicles move can help cities plan roadway infrastructure improvements, make land-use decisions, plan for special events, reduce traffic fatalities, monitor public health, boost economic activity, reduce commute times, mitigate greenhouse gas emissions, and so much more.
In many cases, cities will install physical sensors on the road that capture data on vehicle volumes, speeds, turning movements, and more. But these sensors are too expensive to install on every roadway, and they may not capture non-vehicle traffic such as bikes and pedestrians.
To get more comprehensive and cost-effective insights on how people move, cities often supplement physical roadway sensors with big data analytics. Big data platforms like StreetLight collect, process, anonymize, and validate massive numbers of datapoints from connected devices and the Internet of Things to make precise inferences about how people move.
Data privacy assurances are crucial when collecting big data on mobility. That’s why StreetLight’s Route Science® algorithm anonymizes and aggregates all datapoints, to ensure individuals can never be identified or tracked.
Sensors connected to traffic lights help smart cities automatically synchronize smart traffic signals.
In addition to smart traffic signals (mentioned above), which typically use data on vehicle volumes and speeds, there are many other ways cities are using transportation data. Common examples include:
Vehicle volumes to fix traffic jams, ensure smooth traffic flow during special events, and prioritize infrastructure investments
Speed data to understand where congestion or unsafe speeds are impacting mobility for residents and visitors
Truck activity and routing data to move goods efficiently, highlight emissions hotspots, or reduce dangerous cut-through traffic in residential areas
Real-World Examples of Smart City Transportation Projects
Cities across the globe are using transportation data to make smarter decisions. Here are just a few examples of smart city transportation projects in the U.S. and Canada.
Temecula Retimes Traffic Signals
After securing safety funds for new smart signals, Temecula, California needed intersection data to understand which signals were most in need of synchronization.
They used StreetLight’s turning movement counts to diagnose congestion across 40 intersections within a few hours, saving at least three months on data collection and analysis, and deploying funds effectively to optimize signal timing.
Vancouver Makes the Case for Bus Infrastructure
Multimodal transportation options help reduce congestion, improve climate impact, and ensure equitable access to essential goods and services. But with many transit agencies facing exceptionally tight budgets, proving the value of bus infrastructure investments is crucial to getting improvements implemented.
Richmond Measures Equitable Access to Multimodal Transportation
Transportation equity is gaining more attention, with grant programs like Reconnecting Communities and Safe Streets and Roads for All incentivizing projects that expand equitable access. But getting reliable measurements of transportation access is often a barrier to diagnosing and addressing existing inequities impacting city residents, especially among communities of color, low-income households, and people with disabilities.
In the video below, Alex Bell of Renaissance Planning explains how data from StreetLight helped city planners for Richmond, Virginia develop measures of multimodal accessibility and understand who was most underserved by existing infrastructure. This analysis revealed where infrastructure investments were most critical to improve transportation equity throughout the city.
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.
America’s roads just keep getting wider. According to a Washington Post report, over a third of U.S. states spent more than $19 billion on expanding existing highways and road infrastructure in 2019. [1]
It’s a common way to attempt to curb the traffic congestion plaguing U.S. cities, but many transportation buffs say it’s the wrong approach. In fact, America’s road safety troubles may be directly related to its bloated urban corridors. The data appears to indicate that, in many cases, our roads don’t need to be fed more pavement — they need a diet.
The Federal Highway Administration (FHWA) points out that undivided four-lane roads — so ubiquitous in American cities — play host to a wide range of dangerous collisions, from lane-changing side swipes to bike and pedestrian crashes. These crashes are directly related to the volume and speed of traffic, but they’re also tied to the width and layout of the road. And, while it may seem counterintuitive, the path to increased safety without worsening congestion often lies in reducing lanes, rather than adding them, through a method called road diets. [2]
In this article, we’ll explore how road diets work to increase safety not only for vehicles, but also for pedestrians and cyclists. We’ll tackle the following:
What is a road diet?
Key safety considerations
How effective is a road diet?
Considering the alternatives
Finding the best approach with big data
So, What Is a Road Diet?
A road diet, or lane reduction, is a type of traffic calming measure designed to reduce speed and traffic congestion on an existing undivided roadway. Instead of expanding the existing road width with additional lanes, planners reduce the number of standard traffic lanes to make room for other types of lanes or road features.
Road diets are most common on four-lane highways. Typically, planners exchange the existing four driving lanes for a center left-turn lane flanked by two standard driving lanes and bike or pedestrian lanes. Other road diet examples include replacing two lanes with a tree-lined median or adding parking on the sides and narrowing existing lanes.
Photo source: Virginia DOT, reprinted in the U.S. DOT’s Road Diet Informational Guide
Whatever the specific approach, the overarching goal of a road diet is simple: to lower traffic speed and thus reduce the number and severity of crashes. In the process, this measure can also enhance the overall quality of life and appeal of an urban area by making more room for cyclists and pedestrians, expanding common areas, and even adding more green space to popular thoroughfares.
Key Safety Considerations
Understanding the value of road diets first requires an appreciation of just how threatening many of our busy four-lane, undivided roadways are. These popular road layouts are riddled with safety concerns for drivers, passengers, pedestrians, and cyclists alike. Before making any change to an established roadway, it’s essential to understand the dangers of the existing layout.
For Vehicles
In urban and suburban areas, four-lane, undivided highways are hot zones for vehicle-to-vehicle crashes. There are simply too many potential collision points for drivers to track. Such corridors are commonly home to all sorts of collisions:
Rear-end collisions from sudden stops or vehicles waiting to turn
Sideswipe crashes during lane changes
T-bone or angle collisions from cars turning left across oncoming traffic
Multi-car crashes at intersections
These collisions occur due to a range of factors, many of which can be addressed through road diets. High speed differential between lanes or intersecting streets can lead to sudden stops or miscalculations that result in collisions. Left turns across multiple lanes are also inherently dangerous. [2]
The specific traffic patterns and risks vary by location. When assessing the potential benefits of lane reductions, planners need data that allows them to analyze metrics like average speed, speed differentials, average traffic volumes, and typical turn counts at intersections.
For Pedestrians
As problematic as four-lane roads are for vehicle-to-vehicle crashes, they’re even more hazardous for pedestrians. Drivers hit and killed more pedestrians in 2022 than in any year since 1981, and these types of roads are at the center of many such collisions. [3] As one recent study revealed, 97% of the hot spots for pedestrian deaths in the U.S. are multi-lane roads. [4]
Pedestrians cross a multilane roadway.
Crashes on such roads occur for many reasons, from a lack of sidewalks to pedestrians misjudging oncoming vehicles when crossing multiple lanes. However, the central problem on wide urban streets is vehicle speed. Studies show that pedestrians are five times more likely to die from crashes when cars are traveling at 40 miles an hour than at 20 miles an hour.
Here again, data is crucial for determining the right solution. Understanding vehicle speeds, the volume of pedestrian traffic, and the frequency of pedestrian collisions can help planners assess whether a road diet — and which type — would provide an effective solution.
For Cyclists
According to the National Safety Council, more than 850 cyclists died in collisions with vehicles in 2021. [5] Many of these incidents were linked to unsafe road conditions. [6] The FHWA reports that the simple addition of a bike lane could reduce bike crashes by 49% on four-lane roads. [7]
Beyond being an argument for bike lane additions, this is a strong point in favor of considering road diets on cyclist-heavy city roadways. Road diets are designed to reduce traffic speed, and they can make room for more extensive road modifications such as protected bike lanes, which are physically separated from vehicle traffic.
See how dangerous traffic speeds impact walking and biking in your region
Overall, the data shows that road diets are often highly effective at increasing safety. Based on broad studies, the FHWA states that road diets can reduce crashes by between 19% and 47%. [2] In Seattle, a 2008 road diet reduced pedestrian collisions by 80%. The same project saw a 35% increase in cyclist traffic without any increase in bicycle-involved crashes.
To project the impact in a specific area, planners must account for various factors, particularly existing traffic volume. Lane reductions tend to be most effective on roads with between 8,000 and 20,000 average daily vehicles. [8]
Despite these benefits, many people are skeptical of road diets. In Los Angeles, the firefighters union recently launched a campaign against proposed road diets, claiming they would hinder emergency vehicles by increasing congestion. [9] Others argue they would slow down public transportation or simply divert heavy traffic elsewhere. [8]
Broadly speaking, the evidence to support these claims is slim. Although lane-reduction projects occasionally get pulled back, research shows that these road diet failures often occur due to a disconnection between public perception and reality. In other words — the project accomplishes its goal, even if the public thinks it’s not working.
That’s not to say these tactics are the right solution for every safety or traffic congestion problem. However, the evidence does indicate that when planners closely evaluate the many variables of a situation and decide to implement a road diet, the resulting safety enhancements are usually significant. [10]
Finding the Best Approach With Big Data
As noted, road diet success is much more likely with a deep analysis of traffic patterns. Understanding metrics like turning movement counts, average daily traffic volume and speed, speed differentials, and stopping frequency is essential for an accurate assessment of any potential project.
Big data platforms like StreetLight InSight® can expedite data collection when evaluating a potential road diet, providing detailed visualizations of traffic patterns and trends to help planners conduct a thorough road safety audit before making any decisions. This approach also makes the data collection itself safer because agency staff need not put themselves at risk to take manual counts along dangerous roadways. Furthermore, big data can provide a more complete view of roadway conditions than manual counts, which are usually limited to a small snapshot of traffic during peak driving hours on a particular day or a few days.
Many agencies are already using big data to evaluate potential road diets, as well as the success of past road diets. As the video below explains, Maine’s Department of Transportation used Streetlight tools to conduct a detailed analysis of its Bangor Street road diet proposal, filling in critical data gaps to understand turning movement counts, side-road traffic, and complex roundabout traffic flows.
Similarly, a StreetLight analysis of roadway capacity, vehicle speeds, routing patterns, and pedestrian activity suggested that a road diet on Oakland’s Grand Avenue could help address safety concerns without causing major congestion.
Grand Avenue, part of Oakland’s High Injury Network, could be a good candidate for a road diet treatment.
After implementing a road diet, big data transportation analytics also allow planners to easily measure any changes in traffic volumes, routing, safety, and critical metrics like Vehicle Hours of Delay (VHD). These insights simplify the process of assessing project potential and outcomes so planners can do their work more effectively.
For more information on how big data can help you find the best safety solutions for your streets, check out our Safety Data Handbook.
The Washington Post. “Infrastructure plan calls for fixing the nation’s existing roads. Some states are still focused on expansion.” https://www.washingtonpost.com/transportation/2021/05/23/highway-funding-infrastructure/
U.S. Federal Highway Administration. “Road Diet Informational Guide.” https://safety.fhwa.dot.gov/road_diets/guidance/info_guide/ch1.cfm
Journal of Transport and Land Use. “United States fatal pedestrian crash hot spot locations and characteristics.” https://jtlu.org/index.php/jtlu/article/view/1825
National Safety Council. “Bicycle Deaths.” https://injuryfacts.nsc.org/home-and-community/safety-topics/bicycle-deaths/#:~:text=In%202021%2C%20most%20deaths%20occurred,for%20Health%20Statistics%20mortality%20data
NPR. “More cyclists are being killed by cars. Advocates say U.S. streets are the problem.” https://www.npr.org/2022/05/25/1099566472/more-cyclists-are-being-killed-by-cars-advocates-say-u-s-streets-are-the-problem
U.S. Federal Highway Administration. “Bicycle Lanes.” https://highways.dot.gov/safety/proven-safety-countermeasures/bicycle-lanes
AARP. “Road Diets: A Livability Fact Sheet.” https://www.aarp.org/content/dam/aarp/livable-communities/livable-documents/documents-2014/Livability%20Fact%20Sheets/Road-Diets-Fact-Sheet.pdf
Los Angeles Times. “Firefighters launch campaign against Measure HLA, saying ‘road diets’ threaten safety.” https://www.latimes.com/california/story/2024-02-14/firefighters-launch-campaign-against-measure-hla
Scientific Research. “A Comprehensive Study of a Road Diet Implementation in the US and Abroad.” https://www.scirp.org/journal/paperinformation?paperid=127799#:~:text=The%20road%20diets%20were%20implemented,were%20implemented%20across%2066%20projects
See where vehicle speeds are putting all road users at risk
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.
Better Budget Planning with Big Data: 4 Ways Transportation Agencies Use Data to Build Budgets, Secure Funds, and Save Money
Better Budget Planning with Big Data: 4 Ways Transportation Agencies Use Data to Build Budgets, Secure Funds, and Save Money
With transportation agencies across the U.S. facing a dreaded “fiscal cliff,” budget challenges are top of mind for many StreetLight users. Thoughout the year, but especially as fall approaches, transportation professionals are under pressure to make next year’s budget as efficient as possible, and find last-minute ways to use remaining funds effectively before they’re lost in the budget rollover.
Recent years have introduced added complexity to the budgeting process. While the Bipartisan Infrastructure Law (BIL) passed in November 2021 offered billions in new funding opportunities, the traffic disruptions of the pandemic also introduced added difficulty in anticipating travel demand, planning projects, and following through on existing plans.
Amid these challenges, big data–powered traffic analytics are helping agencies with a few key budgeting needs:
Planning and prioritizing next year’s projects to build effective, justifiable budgets
Save money over traditional data collection methods with validated, on-demand data
Secure additional funding with data-supported grant applications
Use leftover funds quickly and effectively, before they are lost in the fiscal year turnover
Below, we’ll explore specific examples collected from panels and discussions that illustrate how shrewd practitioners are using Big Data analytics to meet these budgeting challenges.
1. Prioritizing Projects for Next Year’s Budget
At our 2020 StreetLight Summit, when many projects were in limbo, transportation professionals told us they were ramping up on planning. That way, when budgets were settled and projects could begin again, planners would be confident they’d analyzed and prioritized the most important work.
“If we are going to invest in putting up count stations that cannot be moved, we need to be confident there will actually be activity at that count station.”
Although this was top-of-mind during the disruptions of the early COVID pandemic, this insight is evergreen. When agencies have the data to effectively prioritize next year’s projects, that data can also be used as evidence to justify next year’s budget and support its approval.
At the 2020 StreetLight Summit, planners shared examples of running multiple analyses for each project, and studying before-and-after results to measure impact of existing projects.
For example, FDOT needed to decide where to install 11 continuous bike and pedestrian counters along thousands of miles of bike trails and lanes in Florida. Planners instinctively felt that the University of Florida in Gainesville would be a prime location, and took the time to verify that instinct.
“If we are going to invest in putting up count stations that cannot be moved, we need to be confident there will actually be activity at that count station,” explained Eric Katz at FDOT.
Figure 1: A Zone Activity analysis marking potential location for a continuous bike counter on University Avenue in Gainesville, Florida.
Katz confirmed a steady stream of bike/ped travel in the area, plus trip duration and trip speed, by running a StreetLight Zone Activity analysis. The study pinpointed additional Florida locations for short-term counters, including a popular bike trail in the Panhandle.
2. Save Money Over Traditional Collection Methods
To operate effectively, agencies rely on data-informed project planning. But answering key questions about existing mobility conditions can often strain budgets.
Access to on-demand traffic data is often far more cost effective than sensors or surveys, allowing agencies to operate with a more comprehensive understanding of mobility in their communities.
But big data can provide O-D analytics at larger sample sizes without the delay or cost of surveys.
At the 2020 StreetLight Summit, Lucile Kellis of Steer shared an origin-destination analysis designed to help a transit client size unmet travel demand. First, Steer used StreetLight to identify where transit users were ultimately going to and coming from, to highlight strategic travel corridors.
“Good surveys are expensive and they return results with low sample size and biases. StreetLight helps us solve these issues at a much cheaper cost.”
Then they went further by gleaning additional insights about the travelers themselves. But rather than incur what would be an additional survey expense, Steer leveraged the StreetLight InSight® platform.
“Typically our clients have a good understanding of who their customers are, but not the people who they want to attract,” Kellis explained. “Surveys are a good tool to collect that information, but we all know that good surveys are expensive and they return results with low sample size and biases. StreetLight helps us solve these issues at a much cheaper cost.”
Figure 2: Using demographic information from StreetLight InSight® Steer’s analysts built a dashboard capturing transit persona data.
Similarly, when MnDOT wanted to understand sources of traffic on Dodd Road, on-demand traffic analytics helped them avoid prohibitive survey costs.
Figure 3: MnDOT’s analysis confirmed that Dodd Road’s traffic was primarily made up of local trips, not cut-through traffic.
“We normally wouldn’t answer this community question because the survey spend wouldn’t be cost effective,” says Michael Corbett at MnDOT. Corbett’s team was receiving complaints about cut-through traffic in a particular neighborhood. But with unlimited analyses via the agency’s StreetLight InSight® subscription, MnDOT was able to identify the source of neighborhood traffic, and share results with constituents.
Budget limitations often demand that some concerns remain unaddressed, even for well-funded state DOTs and large MPOs. Meanwhile, small to medium-sized cities may have an even tougher time addressing resident reports of cut-through traffic, congestion and delays, or unsafe vehicle speeds.
Access to big data can allow these cities to investigate and validate resident complaints more affordably, shifting funds that would have been spent on data collection to actually implementing solutions. Plus, with information on the entire transportation network, and the ability to evaluate the impact of past projects with before-and-after analyses, cities can more confidently choose the most effective solutions and ensure funds are not wasted.
Other traditional data collection methods — such as automatic traffic counters or manual field observation — can also drive up costs. In 2019, one DOT ran a cost-benefit analysis to compare StreetLight’s platform to traditional methods and found a 50:1 benefit-cost ratio (click here to learn more about cost-benefit analyses).
“We normally wouldn’t answer this community question because the survey spend wouldn’t be cost effective.”
3. Secure Grant Funding
Data-supported grant applications help agencies stretch their budgets and fund projects that might otherwise end up on the chopping block or face considerable delays.
To tell a story grant administrators want to hear, agencies need evidence that their proposed project will significantly benefit their community. But as we’ve explored above, traditional data collection can be costly and time-consuming, leaving agencies with a catch 22.
Big data can help build a compelling grant application with clear visualizations and benefit-cost analyses using recent, validated data on existing conditions.
Big data has also been pivotal in securing funds for safety projects. Agencies that have leveraged StreetLight for Safe Streets and Roads for All (SS4A) applications have won ~$8 Million in SS4A grant funding.
4. Use Funds Effectively Before It’s Too Late
Because many agencies have use-it-or-lose-it funds, the end of the fiscal year often adds urgency to fund implementation. How can agencies use leftover funding effectively for their communities, with limited time left in the year?
Because big data analytics don’t face the same delays that traditional data collection methods do, they can allow agencies to quickly identify optimizations on existing roadways and allocate funds for quick fixes like signal retiming or optimizing bus schedules.
Big data can also help agencies funnel these leftover funds into planning for next year.
For example, when planners in the Shreveport, Louisiana area had concerns about traffic congestion and safety, they used StreetLight to get a comprehensive look at regional traffic, pinpoint congestion hotspots, and quickly build a data-supported mitigation plan.
This approach also relieves budget stress by allowing managers to use their staff resources more efficiently. Chris Petro, AICP, of the Northwest Louisiana Council of Governments (NLCOG) put it this way:
“Without StreetLight’s data, calculating the Speed Reduction Factor would have been monumental in terms of MPO staff time and resources. StreetLight’s team also helped compile, attribute, and format traffic flow data in a GIS environment.”
