Rumbling down the center of the road
AMES, Iowa – June 7, 2010 – In an effort to reduce rural highway centerline crossover crashes, the Iowa Department of Transportation (DOT) has adopted a policy to include centerline rumble strips on certain sections of two-lane highways.
“This is about saving lives,” said Tom Welch, Iowa DOT state safety engineer. “Iowa has already made great strides in implementing strategies that reduce run-off-the-road and crossover crashes, including shoulder rumble strips and cable median barrier. The centerline rumble strips are an additional safety measure.”
Eighteen-inch wide grooves will be milled into the center of the road to alert inattentive drivers when their vehicles are about to cross into the opposite lane. Three test projects for centerline rumble strips have already been installed on U.S. 34 in Union County, U.S. 52 in Dubuque County and U.S. 61 in Des Moines County.
At least 11 other states are currently using centerline rumble strips to reduce crashes on rural, two-lane roads. National statistics show a nearly one-third reduction in head-on crashes in areas where centerline rumble strips have been installed. A 2006 Minnesota study found that after installing centerline rumble strips, fatal and the most serious crashes were reduced by 25 percent per year. A 2001 Colorado DOT study found that head-on crashes decreased by 34 percent and opposite sideswipe crashes decreased by 36.5 percent, based on four years of before-and-after data.
Cross centerline crashes are most prevalent on rural, two-lane roadways with relatively high traffic volumes. To address these areas, the Iowa DOT will add centerline rumble strips wherever pavement upgrades are made on state-maintained roadways with greater than 3,000 vehicles per day. In addition, centerline rumble strips will be installed on any state-maintained roadways with a statistically high number of cross centerline crashes, provided the pavement is in acceptable condition.
Although some motorcycle interest groups have in the past expressed concern about the ability of motorcyclists to maintain control when passing other vehicles on roads with centerline rumble strips, a 2008 research project in Minnesota found no change in rider behavior. The study also showed that while 29 motorcycle crashes occurred on Minnesota roads that had centerline rumble strips, that roadway feature was not listed on any of the crash reports as a contributing factor. Finally, researchers had 32 motorcyclists riding various motorcycle designs evaluate rumble strips on a closed course. The research team found that riders had no difficulty passing over the rumble strips and made no adjustments to throttle, braking or steering during simulated passing operations.
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Contact: Tom Welch at 551-239-1267 or tom.welch@dot.iowa.gov
