SafeTREC

Jaywalking in California: History, Pedestrian Safety Trends, Law Enforcement Patterns, and Decriminalization Legislation

Santos, Mike
Lutzker, Liza
Julia Griswold
2026

This report investigates jaywalking laws in connection with traffic safety, racial equity, and street design, focusing on California. It traces the concept of "jaywalking" to an early 20th-century auto industry campaign to shift safety responsibility from drivers to pedestrians. By analyzing national and California pedestrian injury and fatality data (2009– 2022) alongside California Racial and Identity Profiling Act (RIPA) police stop data (2018–2022), the study describes demographic disparities in both pedestrian crashes and law enforcement of jaywalking. It also documents recent...

Trends in Alcohol-involved Crashes Among Young California Drivers Before, During and After the COVID-19 Pandemic

Lotito, Ainsley
Vaca, Federico E.
Hu, Siwei
Hill, Linda
Julia Griswold
Li, Kaigang
2026

Objectives: To examine changes in alcohol-involved traffic crash rates among young drivers in California during and following the COVID-19 pandemic.
Methods: We conducted a cross-sectional study of alcohol-involved crashes among drivers aged 15–24 using data from the University of California, Berkeley Transportation Injury Mapping System (2016–2024). The primary exposure was COVID-19 policy period (pre-, during-, and post-pandemic). Annual crash rates per 100,000 population were calculated, and Quasi-Poisson regression models estimated rate ratios (RRs) comparing COVID-19 periods,...

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

Schneider, Robert J.
Diogenes, Mara Chagas
Arnold, Lindsay S.
Attaset, Vanvisa
Julia Griswold
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,...

Factors Associated with Hit-and-Run Pedestrian Fatalities and Driver Identification

MacLeod, Kara E.
Julia Griswold
Arnold, Lindsay S.
Ragland, David R.
2010

Because hit-and-run crashes account for a significant share of pedestrian fatalities, a better understanding of these crashes will assist efforts to reduce pedestrian fatalities. Of the more than 48,000 pedestrian deaths that were recorded in the United States between 1998 and 2007 (Fatality Accident Reporting System [FARS]), 18.1% of them were the victims of hit-and-run crashes, and the percentage of fatal pedestrian hit-and-runs has been rising as the number of all pedestrian fatalities has decreased. Using FARS data on single pedestrian fatal victim crashes between 1998-2007, logistic...

Pilot Models for Estimating Bicycle Intersection Volumes

Julia Griswold
Medury, Aditya
Schneider, Robert J.
2011

Bicycle volume data are useful to practitioners and researchers to understand safety, travel behavior, and development impacts. This paper describes the methodology used to develop several simple models of bicycle intersection volumes in Alameda County, California. The models are based on two-hour bicycle counts performed at a sample of 81 intersections in the Spring of 2008 and 2009. Study sites represented areas with a wide range of population density, employment density, proximity to commercial property, neighborhood income, and street network characteristics. The explanatory variables...

Pedestrian Safety Improvement Program

Grembek, Offer
Bosman, Crakg
Bigham, John M.
Fine, Sara
Julia Griswold
Medury, Aditya
Sanders, Rebecca L.
Schneider, Robert J.
Yavari, Afsaneh
Zhang, Yuanyuan
Ragland, David R.
2014

The Pedestrian Safety Improvement Program is an effort of the California Department of Transportation (Caltrans) to identify and address systemic problems with regard to pedestrian safety in California, with the long-term goal of substantially reducing pedestrian fatalities and injuries in California. The efforts and findings presented in this report reflect the work of a team of experts in transportation engineering, transportation planning, public health, geographic information systems, and urban design from the UC Berkeley Safe Transportation Research & Education Center.

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

Julia Griswold
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]

Julia Griswold
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...

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

Hsu, Cheng-Kai
Tsao, Melody
Moran, Marcel E.
Julia Griswold
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...

Creating a Data Resource of California Police Stops for Use in Traffic Safety Applications | Safe Transportation Research and Education Center

Julia Griswold
2025

Traffic stops are one of the most common ways in which the American public interacts with police. Although one of the leading reasons given for police traffic stops is a violation of the vehicle code, there is limited and mixed research on the impact of traditional police traffic enforcement on traffic safety outcomes. At present, few large data resources with an appropriate level of detail exist to facilitate investigations of this type. The 2015 Racial and Identity Profiling Act (RIPA) requires all law enforcement agencies in California to collect and submit vehicle (including bicycle)...