Investigating the Effect of Roadside features on Single-Vehicle Roadway Departure Crashes on Rural Two-Lane Roads

摘要

One of the most important tasks in traffic safety is to investigate the relationshipbetween motor vehicle crashes and the geometric characteristics of roadways. There is alarge amount of previous work that has provided meaningful results in knowing the impactsof geometric design on crash frequency. However, little attention has been paid in finding therelationship between road departure crashes and relevant roadside features such as lateralclearance, side slope condition and driveway density. The lack of roadside data forestimating rigorous statistical models has been a major obstacle of roadside safety researchfor many years. The objective of this paper is to investigate the relationship between single11vehicle roadway departure crashes and roadside features. Two types of models weredeveloped: Crash frequency models using a negative binomial model and crash severitymodel using a multinomial logit model. The objective was accomplished by using field datacollected in four districts in Texas. The results of this study show that shoulder width, lateralclearance 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 orshoulder width and when the side slope condition becomes worse. Driveway density is notfound to be significant in influencing the crash frequency or their severity.