Study Details

Study Title: Developing Crash Modification Factors to Quantify Impacts of Pedestrian Countdown Signals to Drivers

Authors: Kitali et al.

Publication Date:JAN, 2017

Abstract: Pedestrian countdown signals (PCSs) are viable traffic control devices that assist pedestrians to cross intersections safely. Despite the fact that PCSs are meant for pedestrians, they also have an impact on driver behavior at intersections. This study focuses on evaluation of safety effectiveness of PCSs to drivers in the cities of Jacksonville and Gainesville, in Florida. A before-after study with empirical Bayes method was used in analyzing the vehicle crash data for the two cities, state maintained intersections with PCSs. Prior to establishing Crash Modification Factors (CMFs), full safety performance functions for different crash types and severities were estimated using the negative binomial regression model. From the predicted crash counts, the CMFs were established for distinctive categories of crashes based on crash severity types. The findings indicated that installing PCSs revealed a significant improvement of driver’s safety by 8.8% reduction in total crashes, 4.8% reduction in fatal and injury crashes, and 7.1% reduction in property damage only crashes. In addition, rear-end crashes were observed to be reduced by 8.0% whereas a 4.6% reduction in angle crashes was observed. Also, discussed in this study, are the crash modification functions (CMFunctions) showing the relationship between the developed CMFs and average daily traffic volume in the major street at the intersection were developed. In summary, the results suggest usefulness of PCSs for drivers.

Study Citation: Kitali, A., T. Sando, A. Castro, D. Kobelo, and J. Mwakalonge. "Developing Crash Modification Factors to Quantify Impacts of Pedestrian Countdown Signals to Drivers". Presented at the 96th Annual Meeting of the Transportation Research Board, Paper No. 17-05178, Washington, D.C., (2017).

Related Citations: Kitali, A. and T. Sando. "A full Bayesian approach to appraise the safety effects of pedestrian countdown signals to drivers". Accident Analysis and Prevention, Vol. 106, (2017) pp. 327-335. Kitali, Angela E., et al. "Using Crash Modification Factors to Appraise the Safety Effects of Pedestrian Countdown Signals for Drivers." Journal of Transportation Engineering, Part A: Systems 144.5 (2018): 04018011.

CMFs Associated With This Study

Category: Intersection traffic control

Countermeasure: Install pedestrian countdown timer

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.9128.85 StarsAllAllNot specified
0.9524.84 StarsAllK,A,B,CNot specified
0.9297.15 StarsAllONot specified
0.9285 StarsRear endAllNot specified
0.9544.64 StarsAngleAllNot specified
CMF Equation5 StarsAllAllNot specified
CMF Equation5 StarsAllK,A,B,CNot specified
CMF Equation5 StarsAllONot specified
CMF Equation5 StarsRear endAllNot specified