How do centerline rumble strips increase highway safety?
Centerline rumble strips are effective at reducing head-on, sideswipe and crossing-the-centerline crashes on two-lane, rural highways. These crashes are of great public concern because they often impact innocent motorists and passengers in a second vehicle. The crash cause is typically driver inattention, error, fatigue, or impairment. An Insurance Institute for Highway Safety study showed all crash types were reduced by 15 percent, while head-on and opposing direction sideswipe crashes involving injuries were reduced by 25 percent.
Data compiled by the Insurance Institute for Highway Safety from: “Crash Reduction Following Installation of Centerline Rumble Strips on Rural Two-Lane Roads, IIHS, September 2003
In the year 2000, 20 states had a combined total of 200 miles of centerline rumble strips on a few roadways. The five states with the most miles comprised 100 miles total. By the year 2003, 22 states were using centerline rumble strips for a combined total of approximately 1100 miles. The top five states had 850 miles. Since 2003, at least two states (Pennsylvania and Missouri) have new policies to install centerline rumble strips statewide on their two-lane rural roads.
Kansas State University
Two-Lane, Two-Way Highway Experience
Alaska installed centerline rumble strips in 2000 on horizontal curves on the Seward Highway along Turnagain Arm. Centerline rumble strips were added to Turnagain Hill in 2003 which had a history of head-on collisions. In 2007, two isolated, high crash curves with an increasing history of fatalities over the last five years were also treated on the Sterling Highway (MP 52 and MP 168). Head-on collisions and fatalities have been significantly reduced since these installations. There is not enough data on these short segments to justify drawing conclusions until more years pass. However, data from other states suggests they will be effective at reducing severe crashes in the long term.
Washington reported a 37 percent decrease in crossover collisions and a 55 percent decrease in fatal and disabling crossover collisions over a two year period. This was for 107 miles of rural two lane highway where centerline rumble strips were installed in both passing and no-passing areas.
In Delaware, average yearly head-on collisions decreased by 95 percent after the installation of centerline rumble strips on both passing and no-passing areas on a high crash section of US 301, 3 miles long. Crashes caused by motorists crossing the centerline decreased by 55 percent. Even with a four percent average yearly increase in traffic volumes, there were no fatal accidents reported during the seven-year period after installation of the centerline rumble strips. There were 2 per year in the “before” period (1991-1994)
Nebraska noted a 44 percent reduction in combined fatal and injury crashes following the installation of centerline rumble strips in both passing and no-passing zones.
Missouri conducted a before and after study on a pilot project that implemented centerline rumble strips in 2003. They reported a 60 percent reduction in all crossover centerline crashes and an 84 percent reduction in severe crossover centerline crashes.
Source: Benefit-Cost Evaluation of MoDOT’s Total Striping and Delineation Program, Report # OR09-014, MoDOT, November, 2008.
Minnesota studied 203 miles of roadway, showing every key crash statistic decreased, even those that are typically increase with traffic growth. Total fatal and most severe (Type ‘A’) crashes decreased by 25%. The crash rate and severity rate both decreased by more than 10 percent, even while average annual daily traffic (ADT) increased by nearly 10 percent.
Source: Safety Effects of Centerline Rumble Strips in Minnesota, Report #MN/RC-2008-44, MnDOT