In recent years, the United States Department of Transportation (USDOT) has placed greater emphasis on reducing drowsy driving. One state in whichdrowsy driving has been identified to be of concern is the state of Utah. Due to the seriousness of drowsy driving in the state of Utah, it was important to evaluate the impact of drowsy driving in the state, to identifylocations where drowsy driving may be a contributing factor to current crashes, and to identify the effectiveness of countermeasures to help offsetthe impact of drowsy driving. One of the primary countermeasures evaluated was the creation and installation of drowsy driving signs along Interstate 80 (I 80) between Wendover and Salt Lake City, Utah. This paper summarizes the results of research performed to identify corridors in which driver fatigue is a causal factor for crashes while reporting on the effectiveness of drowsy driving signs on I 80. It was determined from the research that the eastbound percent reduction in drowsy driving crashes was statistically significant at an 85 percent level of significance and ranged from 46 percent to 63 percent. The westbound reduction ranged from 5 percentto 22 percent, but was not statistically significant. Additionally, a public opinion survey indicated that the drowsy driving signs definitely or somewhat contributed to the driver's decision to exit the freeway and take a break for 32 percent of survey participants.
Abstract