Horizontal curves have been identified as a target area for improving safety on rural two-lane roads in Texas. This study uses multinomial logit models to assess driver injury severity resulting from single-vehicle crashes on such roads. Likelihood ratio tests warranted the development of separate severity models for small, medium, and large radius curves. Variousdriver, vehicle, roadway, and environmental characteristics were found toimpact injury severity among the 10,029 crashes analyzed. Run-off-the-road crashes, particularly those resulting in collisions with roadside objects, were found to increase injury severity. Females were more likely to sustain injury and older drivers were more likely to be critically injured,particularly on smaller radius curves. Various driver actions and behaviors were also significant determinants of injury severity. Lack of safetybelt use increased fatalities by a factor of ten while drivers who were uninsured, fatigued, or under the influence of drugs or alcohol were also likely to be more seriously injured. Several of these behavioral factors were more pronounced on sharper curves. In addition to ongoing engineeringinitiatives, targeting driver behavior appears to have the potential for creating further improvements in safety on rural two-lane curves.
Abstract