Study Details

Study Title: Investigating the Effect of Roadside Features on Single-Vehicle Roadway Departure Crashes on Rural Two-Lane Roads

Authors: Yichuan Peng, Srinivas Reddy Geedipally, and Dominique Lord

Publication Date: JAN, 2012

Abstract: One of the most important tasks in traffic safety is to investigate the relationship between motor vehicle crashes and the geometric characteristics of roadways. There is a large amount of previous work that has provided meaningful results in knowing the impacts of geometric design on crash frequency. However, little attention has been paid in finding the relationship between road departure crashes and relevant roadside features such as lateral clearance, side slope condition and driveway density. The lack of roadside data for estimating rigorous statistical models has been a major obstacle of roadside safety research for many years. The objective of this paper is to investigate the relationship between single vehicle roadway departure crashes and roadside features. Two types of models were developed: Crash frequency models using a negative binomial model and crash severity model using a multinomial logit model. The objective was accomplished by using field data collected in four districts in Texas. The results of this study show that shoulder width, lateral clearance and side slope condition has a significant effect on the roadway departure crashes. The crash frequency and severity will increase when there is a decrease in lateral clearance or shoulder width and when the side slope condition becomes worse. Driveway density is not found to be significant in influencing the crash frequency or their severity.

Study Citation: Peng, Y. and S.R. Geedipally, and D. Lord. " Investigating the Effect of Roadside Features on Single-Vehicle Roadway Departure Crashes on Rural Two-Lane Roads." Presented at the 91st Annual Meeting of the Transportation Research Board, January 22-26, Washington, DC, 2012.

Study Report: Download the Study Report Document


CMFs Associated With This Study

Category: Roadside

Countermeasure: Improve sideslope rating from 5 to 1

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.1 90 2 Stars Run off road,Single vehicle K,A,B,C Not Specified Rural
0.1 90 2 Stars Run off road,Single vehicle K,A,B,C Not Specified Rural

Category:Shoulder treatments

Countermeasure: Increase shoulder width from 0 to 10 feet

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.29 71 3 Stars Run off road,Single vehicle K,A,B,C Not Specified Rural
0.13 87 3 Stars Run off road,Single vehicle K,A,B,C Not Specified Rural