Iowa Department of Transportation’s Iowa Statewide Centerline Rumble Strip Project installed centerline rumble strips on 1,680 miles of undivided two-lane primary highways across the state. The $8.4 million project increased centerline rumble strip roadway coverage from 62 percent to 91 percent, with Iowa DOT planning to keep increasing roadway coverage with centerline rumble strips to near 100 percent.
The agency maintains about 6,500 miles of undivided roadways where centerline rumble strips could be utilized; a roadway treatment that alerts drivers to a lane deviation and warn the driver to safely correct the vehicle. They can especially be effective with drowsy, distracted, inexperienced, elderly, and even impaired drivers, Iowa DOT said. Iowa DOT effectively utilized a simple, low-cost “Safe Roads” solution on a statewide centerline rumble strip program to yield a high-impact safety benefit through significant decreases in roadway crashes, injuries, and fatalities. The agency said results are encouraging.
In 2025, fatalities and serious injuries from lane deviation crashes decreased to 790 or 12 percent below the previous five-year average. Iowa DOT said the project used a variety of state and federal resources, with the Infrastructure Investment and Jobs Act providing funding through the Highway Safety Improvement Program, National Highway Performance Program, and Surface Transportation Block Grant funds.
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