Iowa DOT testing audible warnings on attenuators to better protect road crews

Updated Aug 1, 2018
Iowa DOT is trying out a new attenuator, seen here on the left, that alerts drivers to the presence of a road crew with both audible and visual warnings. Photo: Iowa DOTIowa DOT is trying out a new attenuator, seen here on the left, that alerts drivers to the presence of a road crew with both audible and visual warnings. Photo: Iowa DOT

The Iowa Department of Transportation has been trying out a new type of attenuator to protect workers and drivers in work zones, and, as the agency reports, so far, so good.

A wrecked attenuator following a work zone crash. Photo: Iowa DOTA wrecked attenuator following a work zone crash. Photo: Iowa DOT

In 2017, IDOT used nine pull-behind attenuators. With more than half of U.S. highway contractors reporting work zone crashes, attenuators are an integral tool used by road crews to protect workers. As the last vehicle in the chain that is placed between roadway workers and the traffic flow, the attenuator warns drivers of the work under way, and provides a buffer to protect workers from traffic and potential crashes.

When wrecked, the replacement cost for each attenuator is $14,000. If the lighted arrow board attached to the attenuator is damaged, that’s another $2,300 in replacement costs.

In the hopes of making these mobile protective barriers even more capable in heading off crashes, the agency is testing the utility of a new audible attenuator warning system that ups driver awareness of road work with both visual and audible warnings.

As you can see in the video below, the new system flashes six yellow lights beneath the arrow board and blares a siren that sounds a bit like those found on ambulances.

“Because we work so closely with other states on equipment, we’re able to share ideas and new technologies,” says Ken Morrow, Iowa DOT  Office of Maintenance.

“A few years ago, we went down to Saint Louis to see an audible system they were using to protect workers on their paint crew. The system uses much brighter flashing lights and emits a unique sound geared towards getting driver’s attention.

“It took a while to work everything out, but this summer we’re testing two systems on our paint crews in central and eastern Iowa and will be adding eight more systems all over the state later this summer.