This report examines contributing factors to single vehicle off-roadway, rear-end, and lane change crashes involving light vehicles (passenger cars, sport utility vehicles, vans, and pickup trucks). The analysis is based on crash data obtained from the National Automotive Sampling System's 1997-2000 Crashworthiness Data System (CDS) and 2000 General Estimates System (GES). Research on crash contributing factors was divided into three phases: phase one provides a comparison of CDS and GES contributing factor distributions; phase two examines crash severity in relation to contributing factors; and phase three determines contributing factors based on pre-crash scenarios. This report classifies crash severity into severe and less severe crashes based on whether or not the vehicle involved in a crash was towed from the scene due to damage. Results from phase one indicate that contributing factor distributions for the CDS and GES matched fairly closely; however, discrepancies were found for inattention and speeding. Phase two results found that contributing factors were similar in the majority of crash types regardless of the severity of the crash; however, the relative frequency of alcohol/drugs and sleepy/drowsy were found to be influenced by crash severity for single vehicle off-roadway and rear-end crash types. Phase three results showed that the contributing factors were influenced more by the critical event than the vehicle movement prior to the critical event in precrash scenarios leading to single vehicle off-roadway crashes.
Samenvatting