Study Details

Study Title: Safety Evaluation of Alternative Audible Lane Departure Warning Treatments in Reducing Traffic Crashes: an Empirical Bayes Observational Before-After Study

Authors: Wu et al.

Publication Date:JAN, 2018

Abstract: Roadway departure crashes are a major contributor to traffic fatalities and injury. Rumble strips have been shown as an effective countermeasure in reducing roadway departure crashes. However, some roadway situations, for instance inadequate shoulder width or roadway surface depth, have limited the application of conventional milled or rolled in rumble strips. Alternative audible lane departure warning systems include profile (audible) pavement markings and preformed rumble bars have seen increased usage to overcome the limitations that exist with the milled rumble strips. So far, the safety effectiveness of these alternative audible lane departure warning systems has not been extensively assessed. The main purpose of this paper is to examine the safety effect of installing profile pavement markings and preformed rumble bars. Specifically, this study developed crash modification factors for these treatments that quantify the effectiveness in reducing single-vehicle-run-off-road (SVROR) and opposite-direction (OD) crashes. Traffic, roadway, and crash data at the treated sites on 189 miles of rural two-lane highways in Texas were analyzed using empirical Bayes (EB) before-after analysis method. Safety performance functions from the Highway Safety Manual and Texas Highway Safety Design Workbook were used in the EB analysis. The results revealed a 21.3 percent reduction in all SVROR and OD crashes, and 32.5 to 39.9 percent reduction in fatal and injury SVROR and OD crashes after installing profile pavement marking and preformed rumble bars.

Study Citation: Wu, L., S. R. Geedipally and A. M. Pike. "Safety Evaluation of Alternative Audible Lane Departure Warning Treatments in Reducing Traffic Crashes: an Empirical Bayes Observational Before-After Study". Presented at the 97th Annual Meeting of the Transportation Research Board, Paper No. 18-01098, Washington, D.C., (2018).


CMFs Associated With This Study

Category: Shoulder treatments

Countermeasure: Install alternative audible lane departure warning treatments

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.79213 StarsHead on,Run off road,SideswipeAllNot specifiedRural
0.68323 StarsHead on,Run off road,SideswipeK,A,B,CNot specifiedRural
0.6403 StarsHead on,Run off road,SideswipeK,A,B,CNot specifiedRural
0.87133 StarsHead on,Run off road,SideswipeONot specifiedRural