The Iowa Department of Transportation is planning to install wire barriers in areas along the interstate that were the recent scenes of crashes that resulted in multiple deaths. D.O.T. senior transportation engineer, Troy German, says the plans for the barriers have been in the works as the number of vehicles on the interstates has grown.
German says in the past the volume of traffic was low enough that if someone crossed the centerline, they could make it through without hitting anyone else. He says the volume of traffic has increased, and so have the odds of hitting another car if you cross the median, so the cable prevents those types of crashes. While the cables are intended to be a safety feature, German says they have raised some concerns.
German says people are concerned that they will hit the cable and bounce back into traffic. He says it is not guaranteed that you won’t bounce back into traffic, as it’s a natural reaction to turn back from the cable. But German says at least you would be going in the same direction of traffic. German says the combination of vehicles going in two different directions creates more chance for injuries or death. The wire cables were chose for their cost and the way they react when hit.
German says there are many kinds of barriers, including concrete. He says the concrete barriers don’t give as much and the impact is absorbed by the car, while the cables give more and lessen the impact on the car. German says it costs 65-thousand dollars to install a mile of cable along an interstate. There are some 35 miles installed now and plans for more.
German says they have two years of cable installation planned, but the goal is to go from Des Moines to the Mississippi River on I-80 and parts of I-380, the high traffic volume areas. Seven people have been killed and six injured in a couple of crashes along I-80 in Jasper County where cars crossed the median into traffic on the other side.
German says wire barriers installed along I-35 near Ankeny have proved successful in preventing such crashes. He says newer wire barriers can be hit by a car and lose some posts and still be effective at stopping other cars that run into them.