Holistic Approach to Reduce Rural Roadway Departure Crashes

Two-lane rural roadways generate a disproportionate number of fatal and serious injury crashes. Many safety measures to date have reduced crash severity. As roadway design guides have evolved, they have incorporated changes that address safety needs. Advanced vehicle designs have incorporated features that protect occupants. Regulations have addressed risky driver behavior. Technological improvements have reduced emergency response times and transport times to trauma centers. To mitigate rural roadway departure issues, the engineering, education, enforcement, and emergency response (4E) approach has recently been implemented by some highway transportation agencies. Including nonengineering mitigation measures along with engineering mitigations, such as improved roadway and roadside design, and maintenance practices has had positive effects on rural roadway departure crashes. Improved vehicle designs have had positive effects on severity. Improved emergency response has had positive effects on survival rate. Education and enforcement efforts have had positive effects on driver behavior. The Moving Ahead for Progress in the 21st Century Act emphasizes an application of the 4E approach with full flexibility in the use of Highway Safety Improvement Program and Highway Safety Program funds. This paper advances a holistic analytical approach by coordinating the use of the 4Es and identifies the need for research to support and validate the proposed optimization approach. A data-driven model is presented for optimizing the allocation of 4E resources at the program level to address rural roadway departure crash issues. The same model can be applied at the project level.