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MASON CITY, Iowa - With two recent massive vehicle pileups along Interstate 35 in central Iowa recently, cable barriers may have played a role in preventing injuries and fatalities.
The barriers, which were developed in Europe in the 1980s and were first introduced to the U.S. in the 1990s. They are designed to retain vehicles that drift into medians on multi-lane highways. Compared to concrete and plate beam barriers, the cables flex and the posts they rest on break, allowing them to absorb the energy produced in a crash, as compared to concrete, which tend to bounce vehicles off and into oncoming traffic. Cable barriers also prevent cross-median accidents.
According to the Iowa Department of Transportation, they first installed cable barriers along a 3-mile stretch of I-35 in Ankeny in 2003. In Minnesota, MnDOT installed cable barriers on Interstate 94 northwest of Minneapolis in 2004, according to the Minnesota Department of Transportation. Since then, Iowa has installed 330 miles worth along interstate highways, which accounts for nearly 42 percent of all road miles in the state, while Minnesota has strung 591 miles worth along major roadways. Both states have placed them in high traffic and accident prone corridors.
Iowa DOT Field Services Coordinator Pete Hjelmsted says since that time, they have reduced fatalities significantly.
"With the numbers we have, we have seen that cross-median crashes that end in fatalities have dropped by over 50 percent," Hjelmsted says.
In addition, cable barriers are more cost effective compared to other methods.
"They cost approximately $120,000 per mile. When you compare it to another method such as concrete barriers, that's about 10 percent of the cost for the concrete," Hjelmsted adds.
Iowa DOT is partnering with Iowa State University to investigate where they should be expanded further based on factors such as road curviture and crash history, while MnDOT is adding cable barriers along I-35 between the Iowa border and Albert Lea by this summer.