Evaluation

California Traffic Safety Survey 2025

Ewald, Katrin
Wasserman, Lisa
2025

The 2025 Traffic Safety Public Opinion Study was conducted for the California Office of Traffic Safety (OTS) and the Safe Transportation Research and Education Center of UC Berkeley (SafeTREC). The findings of the 2025 Study are based on a sample size and eligibility criteria similar to previous years of data collection. A total of 2,319 responses were collected in April and May 2025 using an online selfadministered survey. Similar to previous years of the study, the survey panelists were provided through Marketing Services Group, a commercial sample and panel vendor.

The survey...

Evaluation of Wet Weather Accident Causation Criteria

Oh, Soonmi
Ragland, David R.
Chan, Ching-Yao
2008

This report documents findings from analysis of traffic collision data from sites that display high collision rates only under wet pavement conditions. These sites were selected using Caltrans safety engineers’ field reports, Wet Table C “investigation required” locations, and a new approach called Continuous Risk Profile (CRP). The geometric features at the sites were studied via field visits and review of as-built plans. Rapid spatial changes (i.e., vertical and horizontal curve in short distance), narrower lane width, lack of median, and wider total freeway width were some of the...

Drivers, Pedestrians, and Cyclists in California Want Complete Streets: Comparison of Results from Roadway Design Surveys of Pedestrians, Drivers, Bicyclists, and Transit Users in Northern and Southern California

Sanders, Rebecca L.
Griffin, Ashleigh
MacLeod, Kara E.
Cooper, Jill F.
2014

This paper compares findings from two recent surveys on roadway design preferences among pedestrians, drivers, bicyclists, and public transit users along major urban corridors in the metro areas of San Francisco and Los Angeles. Sponsored by the California Department of Transportation (DOT), the research explored design preferences that could increase perceived traffic safety, walkability, bikability, and economic vitality along urban arterials. Results from intercept surveys showed that roadway users desire similar design features along the test corridors, which carry 25,000-40,000...

A Multidimensional Clustering Algorithm for Studying Fatal Road Crashes

Fishbain, Barak
Grembek, Offer
2014

Road fatalities are rare outcomes of events that occur in a small time-space region. Although the exact chain of events for each fatality is unique, there are inherent similarities between road fatalities. The science of road safety is dedicated to identifying such similarities, mainly using statistical analysis tools. Researchers typically analyze patterns that emerge over space, such as hot-spot studies, or patterns that emerge over time, such as before-after studies. Traffic research enumerates 84 parameters that characterize a road fatality. A vast number of papers have tried to...

Develop Methods to Reduce or Prevent Backing Crashes

Cooper, Douglas L.
Duffy, Sarah
Orrick, Phyllis
Ragland, David R.
2009

Workplace motor vehicle incidents at Caltrans are a significant cause of injuries, employee lost time, and property damage. Because backing crashes are major contributors to motor vehicle incidents, identifying and promoting methods of reducing backing accidents is a top priority. According to internal Caltrans’ data, 92.3% of workplace backing crashes were preventable by the driver. Backing crashes are the single largest category of preventable crashes, representing 30% of preventable crashes in the Caltrans fleet. From 1998 through 2007, preventable backing crashes cost Caltrans at least...

Bicycle Helmet Use: Workbook and Guide for Evaluating Community-Based Programs

Geyer, Judy
Cooper, Jill F.
Ragland, David R.
2003

Two thirds of bicycle deaths occur as a result of traumatic brain injury; 88% of these injuries can be prevented by a helmet. In 1994, the State of California passed a law requiring all bicyclists under the age of 18 to wear helmets. Despite these legal obligations, many bicyclists still do not wear helmets. The estimates of bicycle helmet use is disparate throughout the state, with some communities reporting up to 80% use and others, especially inner-city areas, reporting less than 10% use.

The California Office of Traffic Safety (OTS) provides grants for bicycle helmet education...

Child Restraint Use: Workbook and Guide for Evaluating Community-based Programs

Ragland, David R.
Geyer, Judy A.
Cooper, Jill F.
2003

The leading cause of injury and death for children in California is motor vehicle crashes. To prevent these needless tragedies, the California Office of Traffic Safety (OTS), through the Business, Transportation and Housing Agency, funds child passenger safety programs throughout the state. This workbook is designed to be used by these local programs to 1) evaluate the impact of their activities on child restraint use, 2) evaluate results to improve or modify the programs as needed, and 3) meet contractual evaluation requirements. Program evaluations can be difficult for local programs due...

2024 California Traffic Safety Survey Summary

Lisa Peterson
Karen Nguyen Vo
2024

The UC Berkeley Safe Transportation Research and Education Center (SafeTREC) has released the California Traffic Safety Survey 2024. The study was led by Ewald & Wasserman Research Consultants (E&W) and conducted on behalf of the California Office of Traffic Safety (OTS) and SafeTREC.

The California Traffic Safety Survey has been conducted annually since 2010 to gain a better understanding of a range of traffic safety behaviors, and to help inform traffic safety programs and public education campaigns. This year’s survey was conducted with an online panel of California...

Evaluate the Safety Effects of Adopting a Stop-as-Yield Law for Cyclists in California

Iman Mahdinia
Julia B. Griswold
Rafael Unda
Soheil Sohrabi
Offer Grembek
2024

The escalating number of injuries and fatalities among cyclists is a pressing safety concern. In the United States, communities are actively seeking strategies to boost cyclist safety, with some states implementing bike-specific policies, such as stop-as-yield laws, to support cyclists. Stop-as-yield laws allow cyclists to treat stop signs as yield signs. The laws are not yet widely implemented, and their potential safety impact is a subject of debate among transportation experts and advocates. This study investigates how stop-as-yield laws can positively or negatively affect safety and...

Impact of the Community Pedestrian and Bicycle Safety Training: Program Insights from the 2024 Follow-Up Survey

Kyler Blodgett
Chen, Katherine L.
2024

The Community Pedestrian and Bicycle Safety Training Program (CPBST) is a collaborative effort between the Safe Transportation Research and Education Center (SafeTREC) at the University of California Berkeley and California Walks (Cal Walks) with funding from the California Office of Traffic Safety. Its main objective is to promote pedestrian and bicycle safety by educating residents and safety advocates, empowering community partners to advocate for safety improvements in their neighborhoods, and fostering collaborations with local officials and agency staff....