Economic feasibility and related issues of highway shoulder rumble strips

Highway shoulder rumble strips are intended to alert drivers of errant vehicles by providing audible and tactile warning. Although recent literature has advanced the state of knowledge in this subject, a number of information gaps remain. This paper reports research in the economic feasibility of shoulder rumble strips and related issues of technology, design, and maintenance. Specifically, facets of this subject covered include rationale for the use of rumble strips, existing practice, technology of installation, design, noise characteristics, maintenance issues, effect of indented rumble bars on the service life of paved shoulders, effectiveness in reducing run-off road accidents, and cost-benefit of rumble strips. The installation of rumble bars requires partially or fully paved shoulders as a prerequisite, so the cost-benefit of paving shoulders with rumble strips is reported for two-lane highways, multilane highways, and freeways. Results are highly favorable in terms of economic feasibility of installing rumble bars on existing paved shoulders. The installation of rumble bars enhances the economic feasibility of paving shoulders. Design innovations are noted that can address a number of highway operation and maintenance problems.