Transforming Road Safety with Proven Solutions

Centerline rumble strips are proving to be one of the most cost-effective methods for reducing head-on and opposite sideswipe collisions on rural roads. Recent studies conducted by civil engineers at the University of Maine demonstrate that these grooved lines can reduce such incidents by 28% to 48%, saving both lives and significant financial resources.

A History of Innovation in Road Safety

In the early 1990s, when Per Gårder arrived in Maine from Sweden, the concept of rumble strips was virtually unknown in the state. Inspired by personal experiences with road accidents, Gårder dedicated his research to studying shoulder rumble strips, a technology that originated in New Jersey during the 1950s. By analyzing police reports of fatal crashes on Maine's interstates between 1989 and 1993, Gårder discovered that nearly half involved drowsy drivers. The subsequent installation of hundreds of miles of continuous shoulder rumble strips along Maine’s interstates reduced sleep-induced "run-off-road" crashes by an impressive 58%.

Building on this success, MaineDOT began installing centerline rumble strips on state roads in 2006. These strips were specifically designed to address head-on collisions, which pose a significant risk due to the high speeds involved. Bob Skehan, director of MaineDOT’s Office of Safety and Mobility, explained that these collisions are equivalent to crashing into a fixed object at 100 miles per hour. The implementation of centerline rumble strips resulted in a dramatic reduction in head-on crashes, cutting them in half during the initial period and eliminating fatal collisions entirely.

Addressing Community Concerns

Despite their proven effectiveness, the introduction of rumble strips faced resistance from some rural residents concerned about noise pollution. Bill Muir, a neighbor near Route 302 in Bridgton, described the sound as resembling a tractor-trailer shifting gears. In response to these complaints, MaineDOT transitioned to sinusoidal or "mumble" strips in 2018. These quieter alternatives significantly reduce external noise while maintaining the necessary vibration inside vehicles, effectively addressing community concerns.

This shift has been instrumental in gaining public acceptance. According to Skehan, the adoption of mumble strips has virtually eliminated noise-related complaints, allowing MaineDOT to continue expanding the use of rumble strips across the state. Today, all interstate highways in Maine feature edge rumble strips, although centerline grooves remain absent from many rural areas, particularly in the northern part of the state.

Economic Benefits of Enhanced Safety Measures

The economic advantages of centerline rumble strips cannot be overstated. Researchers estimate that the benefits of installing these strips outweigh the costs by a factor of 14. With an installation cost of approximately $3,500 per mile, the long-term savings in terms of reduced medical expenses, property damage, and lost productivity are substantial. Even using a conservative service life of seven years, the study demonstrated that rumble strips pay for themselves and provide additional value.

Jhan Kevin Gil-Marin, co-author of the University of Maine study and now pursuing his PhD at Rensselaer Polytechnic Institute, emphasized the importance of continuing to implement these lifesaving measures. Under the guidance of Ali Shirazi, then principal investigator of the Maine Transport Lab, Gil-Marin utilized data from MaineDOT to compare crash rates on similar roads with and without rumble strips. His analysis revealed the true effectiveness of centerline rumble strips in preventing deadly collisions.

Future Directions in Road Safety

MaineDOT remains committed to enhancing road safety through the strategic deployment of rumble strips. The agency aims to add approximately 100 miles of these grooves to state roads annually, prioritizing areas with high traffic volumes and fresh pavement to maximize durability. Funding for these projects comes primarily from the federal Highway Safety Improvement Program, with supplementary support from the state.

While rumble strips focus on infrastructure-based solutions, technological advancements also play a crucial role in improving road safety. Modern vehicles equipped with lane departure warning systems and other sensors offer additional layers of protection. However, as transportation safety researcher Steven Lavrenz points out, human error remains a constant factor. Proactively implementing low-cost safety measures like rumble strips across extensive networks of rural roads could prevent countless accidents before they occur.