Estimating the effect of vehicle speeds on bicycle and pedestrian safety on the Georgia arterial roadway network

Daniel Arias, David Ederer, Michael O. Rodgers, Michael P. Hunter, Kari E. Watkins

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Cyclists and pedestrians account for a disproportionate amount of the world's 1.3 million road deaths every year. This is a growing problem in the United Sates where bicyclist and pedestrian fatalities have increased steadily since 2009. A large body of research suggests vehicle speeds are a key contributing factor for crashes. However, few studies of bicycle or pedestrian crash probability incorporate detailed vehicle speed data. This study uses probe vehicle speed data to examine the impact of vehicle speeds on bicycle and pedestrian crashes on the state of Georgia's network of major arterial roadways. The analysis examines 7000 road segments throughout the state in 2017. A Negative Binomial model relates annual crash and speed data on each segment. Models using speed percentiles (85th, 50th and 15th) are contrasted with models using speed differences (85th–50th and 50th–15th percentile). A small set of covariates are included: segment length, number of lanes, Average Annual Daily Traffic, and urbanicity. Results indicate that larger differences in high-end speed percentiles are positively associated with bicycle and pedestrian crash frequency on Georgia arterials. Furthermore, the coefficients on the high end of the speed distribution, measured by the difference in 85th and 50th percentile speeds, have greater magnitude and statistical significance than the low end of the distribution. This research shows a negative relationship between speed and crashes may be flawed, as it does not account for the distributions of speed. The findings in this study suggest that planners and engineers should identify areas with large speed distributions, especially at the high vehicle speeds, and work to reduce the fastest speeds on these roadways. To do so, differences in speed percentiles measured using probe vehicle speeds can be used to determine where high risk areas are located.

Original languageEnglish
Article number106351
JournalAccident Analysis and Prevention
Volume161
DOIs
StatePublished - Oct 2021
Externally publishedYes

Funding

This research was funded by a grant from the Georgia Department of Transportation under Research Project 18-15, “Safety Performance Metric for Decision Making Process.” The authors would also like to acknowledge Daniel Arias for assistance in spatial data management, conflation, and conducting background research.

FundersFunder number
Georgia Department of Transportation18-15

    Keywords

    • Bicycle and pedestrian safety
    • Distribution of speed
    • Probe vehicle speeds
    • Safety performance metrics

    Fingerprint

    Dive into the research topics of 'Estimating the effect of vehicle speeds on bicycle and pedestrian safety on the Georgia arterial roadway network'. Together they form a unique fingerprint.

    Cite this