Applying 4E Mitigation Measures to Reduce Rural Roadway Departure Crashes - A Holistic Approach

摘要

Two-lane rural roadways involve a disproportionately high number of fatal (K) and seriousinjury (A) type crashes. Many safety measures to date have reduced crash severity. As roadwaydesign guides have evolved, they have incorporated changes that address safety needs. Advancedvehicle designs have incorporated features that protect the occupants. Regulations haveaddressed risky driver behavior.In order to mitigate rural roadway departure issues, the 4E (engineering, education,enforcement and emergency response) approach has recently been accepted by the United Stateshighway transportation agencies. The need to include non-engineering mitigation measures alongwith engineering mitigation, such as improved roadway and roadside design and maintenancepractices, have positive impacts on rural roadway departure crashes. Improved vehicle designshave positive effects on severity. Improved emergency response has positive effect on survivalrate. Education and enforcement efforts have potentially positive effects on driver behavior.“Moving Ahead for Progress in the 21st Century Act (MAP-21)” emphasizes on application of4E approach with full flexibility on using Highway Safety Improvement Program (HSIP) fundsin addition to Highway Safety Program (HSP) funds.This paper presents a data driven model for optimizing allocation of 4E resources at aprogram level, and also for optimizing an effective combination of 4E mitigation measures at theproject level to address rural roadway departure crash issues. The purpose of this paper is topromote a holistic analytical approach by coordinating the use of 4Es and to identify the need forfuture research to support and validate the proposed optimization approach.