AI representation of road workers installing and inspecting centerline rumble strips on a rural two-lane highway, a safety measure designed to alert drivers when their vehicles drift across the centerline. Image Credits: ChatGPT.
One simple application of roadside safety innovations yielded strong outcomes across nearly 5,400 miles of rural roads in Michigan. Centerline rumble strips reduced target crashes by 47% and fatal crashes by 51%. The study considered 3 crash types: head-on crashes, side-swipe crashes between vehicles moving in opposite directions, and single-vehicle crashes where the driver departs the road to the left. The data reveal 2,488 target crashes for the before period and 1,306 in the after period. The study revealed a statistically significant reduction in all three types of crashes and a 51% decrease in fatalities within the target group. Their benefit-cost ratio, ranging from 18:1 to 58:1 depending on the discount rate applied in the analysis, showed potential financial gain from preventing severe crashes far exceeded installation costs. A study published in Accident Analysis & Prevention in 2025 examined centreline rumble strips on rural two-lane roads in Maine. It found reductions of between 28% and 48% in head-on, opposite-direction side-Y collisions, with an estimated benefit at least 14 times the installation cost. Another study published in the Journal of Transportation Engineering in 2016 examined the effectiveness of centreline and shoulder rumble strips on rural roads in Kentucky, Missouri, and Pennsylvania. Overall, the report detected A 36.8% reduction in head-on crashes, but the combined reduction in lane-departure crashes was a test assessed to be in the order of 27%
The initiative, led by the Michigan Department of Transportation , emphasises control to avoid vehicles crossing the centerline into the traffic lane. The study compared crash data from the three years before and the three years after the improvements. The findings emphasised that modest improvements in road surfacing, which are relatively low cost, can make a difference for some of the worst crashes occurring on rural high-speed roads. The researchers controlled for snowfall variation by excluding crashes in which snowy or icy pavement was noted as a contributing factor, reducing the chance that winter weather would distort the comparison. The researchers also show the programme’s worth. Research supports the wider use of rumble strips Michigan’s findings are consistent with research conducted in other parts of the United States.
