Newest Resources

Congestion Costing Research Slideshow: New Insights and Better Solutions
This slideshow summarizes a research program that identifies best practices for evaluating congestion impacts, examines the practices used in congestion costing studies such as the Urban Mobility Report, the Global Traffic Scorecard and the TomTom Traffic Index, and provides guidance for identifying optimal solutions.

Congestion Costing Best Practices
This report identifies congestion evaluation best practices. It systematically describes various congestion costing factors including congestion metrics, baseline speeds, traffic data accuracy, congestion exposure, peak to off-peak speed differentials, travel time valuation, accessibility analysis, additional impacts (fuel, risk, emissions, walkability and economic productivity), congestion dynamics, social equity impacts, and research standards. It discusses how these factors influence analysis and describes best practices based on expert recommendations. It examines how these practices are applied in congestion costing studies. This report is more comprehensive and current than most previous studies.

Congestion Costing Critique: Critical Evaluation of Traffic Congestion Costing Studies
This report identifies congestion evaluation best practices and investigates how well they are applied in congestion costing studies such as the Urban Mobility Report, the INRIX Global Traffic Scorecard, the TomTom Traffic Index, and other transportation economic evaluation guides. These studies often violate best practices: they use excessive baseline speeds, overestimate congestion exposure, and overvalue delay time. Much of their estimated congestion costs consist of speed limit compliance: drivers slowing to legal, efficient and safe speeds. Much of their measured long-term growth in congestion costs results from faster off-peak traffic and lower urban speed limits rather than increased congestion delays. More accurate congestion costing is essential for efficient, equitable and responsive planning. This report is more comprehensive than previous studies.

Smart Congestion Relief: Comprehensive Evaluation of Traffic Congestion Costs and Congestion Reduction Strategies
This report investigates the best ways to evaluate the efficiency and equity of potential congestion reduction strategies. It identifies best evaluation practices, applies them to five types of congestion reduction strategies, compares conventional and best practices, and recommends optimal solutions. It finds that conventional analysis exaggerates autonomous vehicle and roadway expansion benefits, and undervalues multimodal planning, transportation demand management (TDM) and Smart Growth solutions. These biases cause transportation agencies to overinvest in automobile infrastructure and underinvest in space-efficient modes and TDM programs compared with what is most efficient, fair and responsive to user demands.

Live Long and Prosper: Local Policies for Improving Children's Health, Success and Happiness
This study uses new research to better understand how community design affects children’s health, success and happiness, and identifies local policies to help achieve related goals. This is important and timely: American children currently have shorter life expectancies, less economic mobility, and less life satisfaction than at previous times and in most peer countries. This is surprising because the U.S. is affluent and technologically advanced, and spends more on healthcare and education per capita than most other countries. This study investigates these problems and potential solutions. It suggests that poor outcomes result in part from automobile dependency and sprawl which increase costs, risks, inefficiencies and inequities. It identifies local policies that help create more compact, mixed multimodal, affordable, physically active and integrated communities.

'Stupendous Potential': Pay-Per-Mile Auto Insurance Would Cut Costs and Traffic Violence (StreetBlog NY)
Lowering car insurance costs doesn't have to eviscerate crash victims' rights. Pay as You Drive (PAYD) gives motorists a new opportunity to save money when they reduce their crash risk by driving less.
"Everybody is better off, you’ve got less crash risk, less pollution and less traffic congestion, because you’re rewarding this very good thing, which is mileage reduction," said Todd Litman, executive director of the Victoria Transport Policy Institute in British Columbia, Canada, who has long studied the policy. "It has absolutely stupendous potential, and so it’s shocking that it hasn’t gotten a lot of traction."

Roadway Costs, User Revenues and Cost Recovery Trends
This study calculates the portion of US roadway expenditures paid by user fees between 1921 and 2023. Most local road spending and a growing portion state and federal highway spending is funded by general taxes; special fuel taxes and tolls now cover less than half of roadway expenditures, and this is declining. Cost-recovery pricing is justified to increase efficiency, reduce traffic problems, and minimize the subsidies non-drivers must pay for facilities they do not use.

Traffic Speed Versus Roadway Capacity
This short report reviews research on the relationships between traffic speeds and roadway capacity (maximum vehicle volumes) and identifies the speeds that maximize traffic throughput. Because shy distances (the safe amount of separation between vehicles in traffic) increase with travel speeds, traffic capacity tends to peak at moderate speeds. Under optimal (dry, clear and level) conditions capacity typically peaks at 25-35 mph (40-60 kph) on urban arterials with cross streets and at 35-50 mph (60-80 kph) on grade-separated highways, reflecting roadway level-of-service (LOS) C to D. This indicates that moderate traffic speeds tend to maximize roadway cost efficiency and infrastructure investment value.

Off-Street Versus On-Street Parking Trade-Offs
Most municipalities require property owners to provide off-street parking to ensure adequate supply. However, since most driveways displace a public on-street parking space, there are trade-offs between on- and off-street supply, and since public parking spaces can serve more users and destinations than private parking, off-street parking mandates often reduce available supply. This study finds that in neighborhoods where households own fewer than two vehicles on average, off-street parking for single-family homes usually reduces total parking availability and driver convenience. Off-street parking also increases housing costs 10-20%, adds 350-800 square feet of impervious surface area, reduces walkability, and increases traffic problems. Reforming mandates is often justified for efficiency and fairness sake.

Parking Management: Comprehensive Implementation Guide
Typical North American communities have three to six parking spaces per vehicle, including many that are seldom used. These facilities are costly. More efficient management can significantly reduce the amount of parking needed to serve motorists’ needs, typically by 20-60%. This guide describes how to plan, evaluate and implement more than two-dozen parking management strategies. It investigates problems with current parking planning, discusses parking facility costs and potential savings from better management, evaluates the impacts and benefits of specific parking management strategies, and describes how to develop an integrated parking management program.

The Mobility-Productivity Paradox: Understanding the Negative Relationship Between Mobility and Economic Productivity.
This study explores a paradox: negative relationships between mobility and economic productivity. Contrary to popular perceptions, increased vehicle travel tends to reduce prosperity. This study indicates that productivity increases with more efficient transportation that reduces the vehicle travel and associated costs required for economic activities. It identifies ways that transportation agencies, business and individuals can better achieve economic goals.