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Before and After Safety Evaluation of California’s and San Diego's Active Transportation Projects

Project Description

California, and the San Diego region in particular, have invested in pedestrian and bike improvements, including sidewalks, protected cycletracks, bike lanes, protected intersections, and other infrastructure improvements to enhance the user experience and promote safety.


However, despite the efforts to improve infrastructure, collisions involving pedestrians and cyclists and persistently low active travel mode share remain significant concerns. The existing literature suggests that the presence and quality of bicycle infrastructure play a crucial role in improving perceived safety among riders and reducing collision rates (Ferenchak & Marshall; Buehler and Pucher, 2020; Fosgerau et al, 2023; Reynolds et al., 2009; Kaths, 2022; Steinacker et al., 2022; Wysling & Purves, 2022). Previous research that specifically examines the effects of pedestrian and bicycle-friendly infrastructure on crash and injury rates have shown mixed results. For example, longitudinal studies on the Safe Routes to School (SRTS) program, which funds both infrastructure and non-infrastructure improvements for pedestrians and cyclists, found that the program reduced collisions amongst active transportation users in California and New York City (Ragland, Pande, & Bigham, 2014; Dimaggio & Li, 2013). However, another SRTS study focused on New York State did not find significant declines in collisions resulting from the program (Kang et al, 2020). In some cases, implementation of bicycle infrastructure caused vehicle-bicycle collisions to increase, but researchers hypothesized that this increase occurred because more cyclists were present on streets with improved bicycle infrastructure (Pedroso et al, 2016; Chen et al, 2012).


California and the San Diego region lacks comprehensive research on both usage and collision rates associated with investments in pedestrian and bicycle infrastructure, which limits our understanding of their effectiveness and impact. Quasi experimental studies using pre/post data surrounding new project implementation is particularly lacking. While the implementation of such projects has received widespread support, there is a need to critically examine their benefits, including bike and pedestrian trips, safety and the reduction of the collision rates throughout California and the San Diego region.


This project will employ cutting edge longitudinal analyses of pedestrian and bicycle crashes and counts around active transportation projects throughout California and San Diego in particular. The educational impact of the preliminary results of this project is reflected in the research paper "TRBAM-24-06053: Evaluating California’s Active Transportation Program: The Safety Benefits of Safe Routes and Crossings to School Projects in Santa Cruz, CA" submitted for the 2024 Transportation Research Board Annual Meeting.


This project's primary outcomes will be to identify pedestrian and bicycle crashes and counts around active transportation projects, and then articulate design and operation solutions captured in the form of a Technical Memo (which will later become a report). The Memo/Report will articulate the underlying mechanisms of these problems and solutions. The study's findings will play a key role in identifying areas of high risks for pedestrians and bicyclists, prompting the implementation of necessary safety measures to enhance pedestrian and bicycle safety conditions. Moreover, the study results are anticipated to highlight essential domains for future CPBS research over the coming five years, benefitting the broader safety research community.


06/01/2023 to 05/31/2024


San Diego State University

Principal Investigator

Bruce Appleyard

San Diego State University

ORCID: 0000-0003-2105-8079

Research Project Funding

Federal: $120,539

Non-Federal: $60,268

Contract Number


Project Number


Research Priority

Promoting Safety

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