Developing equity-aware safety performance functions for identifying hotspots of pedestrian-involved crashes

Area of Science:

• Transportation Safety
• Traffic Engineering
• Quantitative Social Science

Background:

• Disadvantaged areas disproportionately experience traffic crashes.
• Existing road safety management lacks quantitative equity considerations.
• Transportation safety disparities persist despite evident inequities.

Purpose of the Study:

• To propose novel equity-aware safety performance functions (SPFs).
• To quantitatively integrate equity considerations into road safety management.
• To enable distinct treatment of equity-related variables in crash prediction.

Main Methods:

• Developed equity-aware safety performance functions (SPFs) using negative binomial regression.
• Introduced a 'fairness distance' integrated via partial lasso regularization (controlled by parameter λ).
• Applied SPFs to pedestrian-involved crashes at the census tract level in Virginia, USA.

Main Results:

• Equity-aware SPFs diminished the impact of variables like poverty and race ratios on crash frequencies.
• Higher potential for safety improvement (PSI) values were generated for disadvantaged areas.
• Wilcoxon signed-rank tests showed significant differences in PSI rankings when equity was considered.

Conclusions:

• Equity-aware SPFs offer a quantitative approach to harmonize safety effectiveness and equity.
• This methodology supports more equitable decision-making in road safety resource allocation.
• The study advances methods for addressing safety disparities in transportation planning.