#420 Evaluating the effectiveness of urban speed cameras on traffic safety in a period of dramatic change

Principal Investigator
Erick Guerra
Start Date
July 1, 2023
End Date
June 30, 2024
Project Type
Research Advanced
Grant Program
US DOT BIL, Safety21, 2023 - 2028 (4811)
Grant Cycle
Safety21 : 23-24


Speed cameras were installed along segments of Roosevelt Boulevard in June 2020. Two years earlier, the Pennsylvania legislature had approved the camera installation in light of high fatality rates and requests from City officials. In the previous 5 years, the Boulevard had accounted for 14% of the City of Philadelphia’s total traffic fatalities. The twelve-lane at grade highway frequently makes lists of the most dangerous intersections and roadways in the country, a particularly egregious statistics since Philadelphia has only about half the national traffic fatality rate. Just three months earlier, Covid-19-related shutdowns dramatically influenced the geography of travel and traffic safety. Collision rates and traffic fatalities skyrocketed throughout the city, likely a result of a combination of decreased congestion, increased drunk driving, and decreased traffic enforcement in the wake of protests against the murder of George Floyd and for police reform.
This project examines the effectiveness of the Roosevelt Boulevard using a differences-in-differences approach with a Bayesian Poisson and Negative Binomial models. Selection of control segments will be of utmost importance given the dramatic changes in crashes and fatalities over the period of study. Findings will help inform whether to continue the Boulevard speed camera program, increase the use of speed cameras throughout the state, and potentially liberalize state laws that prevent municipalities from deploying automated speed enforcement without state legislation. Partners include the City of Philadelphia, the Philadelphia Parking Authority, and PennDOT.


Strategic Description / RD&T
This project relates directly to the US DOT’s top research priority of improving safety. Understanding why and where traffic fatalities have increased is critical to developing successful approaches to improving safety outcomes. The US is an outlier in terms of wealthy countries in terms of its overall fatality rates and safety trends of the past two decades. While automated enforcement is a proven way to improve traffic safety, few studies have been conducted on dangerous arterial roadways in the US or internationally. The research will also contribute directly to the US DOT’s third research priority of addressing equity issues. Traffic fatalities and their recent uptick disproportionately affect people of color, particularly Black residents. Roosevelt Boulevard passes through multiple majority Black and majority Hispanic neighborhoods in northeast Philadelphia.
Deployment Plan
This project does not produce a deployable product but a series of findings to be used in supporting the deployment of automated enforcement throughout Philadelphia and PA.
Expected Outcomes/Impacts
The initial analysis has already contributed to an extension of the automated enforcement pilot project. Continued study will support efforts to expand automated enforcement to other corridors in Philadelphia and other parts of Pennsylvania.
Expected Outputs
This project will result in a peer-reviewed publication and several conference presentations. If legislation is continues and allows continued or additional automated speed enforcement, we will also continue to study the safety effects and provide analysis to the City of Philadelphia as part of its Vision Zero reporting efforts.
Of the papers reviewed for this proposal, just four are from a US context, with two evaluating the same program in Charlotte, NC (Cunningham, Hummer, and Moon 2008; Moon and Hummer 2010; Retting and Farmer 2003; Shin, Washington, and van Schalkwyk 2009). The US has unusually high traffic fatality rates for a high-income country and automated enforcement presents one opportunity to reduce traffic deaths. The project also focuses on a particularly dangerous type of roadway, an urban arterial with 40-to-45mph speed limit. Merlin, Guerra, and Dumbaugh (2020) identified arterials as one of the only feature of the built environment consistently associated with worse traffic safety outcomes across 54 studies examining linkages between the built environment and traffic collisions and injuries. Most studies of speed camera effects examine placements along highways or on urban streets with lower speed limits. The study also offers insight into the effects of speed cameras during a period of rapid changes in travel behavior, enforcement, and safety. 

Individuals Involved

Email Name Affiliation Role Position
erickg@upenn.edu Guerra, Erick University of Pennsylvania PI Faculty - Tenured


Amount of UTC Funds Awarded
Total Project Budget (from all funding sources)


Type Name Uploaded
Data Management Plan Data_management_plan_hA8HKCj.docx Aug. 3, 2023, 10:07 a.m.
Publication Evaluating the Effectiveness of Speed Cameras on Philadelphia’s Roosevelt Boulevard. March 13, 2024, 8:55 a.m.
Presentation Evaluating the Effectiveness of Speed Cameras on Philadelphia’s Roosevelt Boulevard. March 13, 2024, 8:55 a.m.
Progress Report 420_Progress_Report_2024-03-31 March 13, 2024, 8:56 a.m.
Presentation The Future of Automated Traffic Enforcement March 14, 2024, 8:28 a.m.

Match Sources

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Name Type
City of Philadelphia Deployment & Equity Partner Deployment & Equity Partner
PA Safe Roads PAC Deployment & Equity Partner Deployment & Equity Partner