CHARACTERISTICS OF AND POTENTIAL TREATMENTS FOR CRASHES ON LOW-VOLUME, RURAL TWO-LANE HIGHWAYS IN TEXAS

Low-volume, rural two-lane highways carry less than 8% of the total vehicle miles on state-maintained (or on-system) highways and have approximately 11% of the total on-system vehicle crashes. These roadways also have relatively more severe injuries when vehicle crashes do occur. For example in 1999, about 26% of the Texas on-system crashes were KAB crashes (i.e., fatal, incapacitating injury, on non-incapacitating injury crashes), while over 40% of the crashes on low-volume on-system roads in 1999 were KAB crashes. In general, crashes on low-volume, rural two-lane highways occur between intersections by a single vehicle running off the road. Crashes on curves and in dark, non-lighted conditions are more common on low-volume, rural two-lane highways than on urban roads. The study in crash characteristics also demonstrated that more KAB crashes occurred in eastern counties than western counties in Texas. A sample of counties was selected to investigate which regional characteristics are associated with high and low crash rates. In general, sites in the eastern counties had less driver-friendly characteristics--more horizontal and vertical curves, narrower lanes and/or shoulders, less forgiving roadside development, higher access density, and higher roadside development scores. Eastern counties also had more crashes at intersections than western counties. To obtain information about the types of treatments being used on these types of facilities, a mailout survey was distributed to the Texas Department of Transportation districts and to other states. A literature review was conducted to identify the known effectiveness of treatments used on rural two-lane highways.