SafeTREC

A Context-sensitive Roadway Classification Framework for Speed Limit Setting in the US

Hsu, Cheng-Kai
Tsao, Melody
Moran, Marcel E.
Griswold, Julia B.
Schneider, Robert J.
Bigham, John M.
2025

In the US, speed limit setting (SLS) procedures have historically relied on driver-behavior-based methods, such as the 85th percentile speed, which are considered objective and allow for consistent application. However, this approach has notable shortcomings, including drivers’ tendency to underestimate their speeds, speed creep, and insufficient consideration of vulnerable road users, which may conflict with the Safe System Approach and Vision Zero initiatives endorsed by the USDOT (US Department of Transportation). In contrast, context-sensitive approaches, which classify roads based on...

Methodology of Large-Scale Annual Average Daily Bicycle Traffic Estimation

Miah, Md Mintu
Griswold, Julia
Proulx, Frank
Bigham, John
Banerjee, Ipsita
Grembek, Offer
2025

Abstract Large-scale bicycle network design, safety, and crash estimates largely depend on network-wide bicycling volume estimation. Previous studies developed direct demand models on a smaller scale (e.g. city or county) where bicycle count and ...Practical Applications Agencies often need to estimate bicycle volumes at the link level across entire networks for planning, safety, and design purposes. This study uses expansion factors to introduce a method for converting short-term site volume data.

ArcGIS GDB for CPBS Report 23UCB01 - A Context-sensitive Street Classification Framework for Speed Limit Setting [supporting dataset]

Griswold, Julia B.
Hsu, Cheng-Kai
Tsao, Melody
Schneider, Robert J.
Bigham, John M.
Moran, Marcel E.
2024

In the US, speed limit setting (SLS) has historically relied on driver-behavior-based approaches, such as using the 85th percentile speed. While these approaches are considered objective and allow for consistent application, they have significant limitations, including drivers’ tendencies to underestimate their speeds, the phenomenon of speed creep, and inadequate consideration of vulnerable road users. These issues may conflict with the Safe System Approach and Vision Zero initiatives endorsed by the USDOT (US Department of Transportation). In contrast, context-sensitive approaches...

A Context-sensitive Street Classification Framework for Speed Limit Setting [supporting dataset]

Griswold, Julia B.
Hsu, Cheng-Kai
Tsao, Melody
Schneider, Robert J.
Bigham, John M.
Moran, Marcel E.
2024

In the US, speed limit setting (SLS) has historically relied on driver-behavior-based approaches, such as using the 85th percentile speed. While these approaches are considered objective and allow for consistent application, they have significant limitations, including drivers’ tendencies to underestimate their speeds, the phenomenon of speed creep, and inadequate consideration of vulnerable road users. These issues may conflict with the Safe System Approach and Vision Zero initiatives endorsed by the USDOT (US Department of Transportation). In contrast, context-sensitive approaches, which...

ITS Staff Spotlight: Matthew Raifman

August 28, 2025

Matt Raifman _ Scooter SpotlightFeatured Center: SafeTREC

Name: Matthew Raifman

What’s your hometown?

“Charm City” Baltimore, Maryland

What is your role at ITS, describe your job in four words, and how long have you been here?

I’m a senior researcher at Safe Transportation Research & Education Center (...

The Analysis of Right-of-Way for Different Road Users in China: Passing-Passenger-Unit Versus Passenger-Car-Unit

Xiong, Wen, Professor
Zhang, Yuanyuan, PhD
Chen, Xiaohong, Professor
Jiang, Chao
2014

Being a public resource, the roadway space was distributed between different road users based on the Passenger-Car-Unit (PCU) concept. However, this concept tends to under estimate the capacity of public transportation and non-motorized travel. To improve the traditional car-oriented design to become more human-oriented, this study proposed a Passing-passenger-unit (PPU) and the method to observe the PPU in roadway level and area level. The PPU data were collected for urban arterials and residential areas in China to test the method and to compare the right-of-way distribution at different...

Safe Routes to School Local School Project: A Health Evaluation at 10 Low-Income Schools

Cooper, Jill F., MSW
McMillan, Tracy PhD
2010

Routes to School National Partnership (Partnership) founded the Local School Project (Project) in 2008 to assist ten schools in lowincome communities to: 1) develop and evaluate a school-based SRTS program, 2) build local capacity to apply for state or federal SRTS funding, and 3) increase safe walking and bicycling to and from the school and in the community. The Centers for Disease Control and Prevention, Kaiser Permanente, and the Robert Wood Johnson Foundation provided funding for the Project.This report presents the results, lessons learned and recommendations identified during the...

Association Between Roadway Intersection Characteristics and Pedestrian Crash Risk in Alameda County, California

Schneider, Robert J.
Diogenes, Mara Chagas
Arnold, Lindsay S.
Attaset, Vanvisa
Griswold, Julia
Ragland, David R.
2010

Each year from 1998 to 2007, an average of approximately 4,800 pedestrians were killed and 71,000 pedestrians were injured in United States traffic crashes. Because many pedestrian crashes occur at roadway intersections, it is important to understand the intersection characteristics that are associated with pedestrian crash risk. This study uses detailed pedestrian crash data and pedestrian volume estimates to analyze pedestrian crash risk at 81 intersections along arterial and collector roadways in Alameda County, California. The analysis compares pedestrian crash rates (crashes per 10,...