Iowa DOT addresses imminent road dangers head-on with light and sound

AMZ4This time of year, our Iowa Department of Transportation maintenance crews turn their focus from plowing snow to making roadway repairs like patching potholes and painting. These activities often take our people out of their trucks on to the roadway, dangerously close to speeding traffic.

The sound and vibration of cars and trucks whizzing by you at 70+ miles per hour is something we learn to live with as we get the job done, but the fear of being hit by an inattentive or speeding driver is real and it takes a toll.

Our equipment is hit multiple times every year and sadly, two of our employees were killed in roadway operations last summer. “We are seeing more and more inattentive drivers or drivers who are going way too fast. Safety has always been at the heart of everything we do, but ensuring the safety of our crews has become a real concern and is top of mind for all of our folks working on the roadways,” explained Brad Fleming of our maintenance bureau.

To reduce the risk to our crews and everyone else who is on the road, we are constantly working to implement the best safety innovations and practices possible.  One of those safety innovations is an “audible attenuator” that we use on short-term, stationary, or slow-moving maintenance operations like pothole patching or painting.

Setting up the safest possible work zone

AttenuatorWhen we’re on the road painting or patching potholes, our work zones consist of several vehicles working in a line on the shoulder or one lane of the roadways. At the rear of the work zone is a specialized vehicle known as an attenuator. An attenuator is the last vehicle in the chain and is designed to provide a buffer between our workers and traffic.

Generally, seeing the attenuator, trucks, and lights of a crew on the roadway are more than enough to warn drivers that something’s going on ahead. But occasionally there are drivers who are paying more attention to their dinner, phone, or passengers than to the road. That is dangerous for all of us.

Over the past few years, many of our attenuators have been equipped with extra lights and the ability to emit a loud sound. When a motorist is approaching too quickly, and our crews feel they are in imminent danger of a crash, the attenuator truck operator has the ability to activate the sound to get the attention of the driver. It has the added benefit of letting the crew ahead know that they should be aware of an approaching driver who could be putting them in danger.  

“The sound is loud by design and we recognize it has the potential to be disruptive to those in the area. We reserve it’s use for times when we feel it could be a life or death situation for our people out on the roads. We hope that those that are hearing the sound recognize the value it brings to the safety of our crews and treat the disruption like sounds they would hear from other emergency response vehicles.” explained Fleming.

Fleming went on to explain that even with these updated safety features, the number of trucks being hit is impacting the willingness of employees to drive the attenuator trucks. He said, “Our crews have a sense of duty to get the job done. They are dedicated to their work, but we have very few employees who haven’t seen or been involved in a near-miss or a crash due to an inattentive driver. When drivers aren’t paying attention, sounding the audible attenuator signals to everyone around that the crew is in imminent danger of being hit. Our crews don’t like the loud sound any more than those who may find it annoying, but to them, it could mean the difference between life and death. Although you may not be aware of these audible attenuators, they are very similar to fire or law enforcement sirens. Just like those sirens, these audible warnings are used to increase the safety of not only our crews but all of those who share the road.”

Corey Baptiste from the central Iowa paint crew has the job of assigning a crew member to drive the attenuator truck. With all the crashes to that vehicle, it’s not an assignment he likes to make.


Chad Rumbaugh, part of the central Iowa paint crew, says while driving the attenuator is dangerous, it helps keep him and co-workers safer. 

Keeping you safely traveling down Iowa’s highways is our main goal. Audible attenuators are just another step in what we are doing to hit this goal. But we can’t do it alone. Help us, help you by paying attention and using all your senses to navigate through work zones whether they are stationary or mobile.

I love LUDMAILA Scott’s comment!

My late husband, Jack Gordon, was on the district one paint crew for 15 years until Hecretired in 1997.

His last years were spent as the garage operations assistant, GOA.

I remember one summer when two of their trucks were hit on I 235 in the Des Moines area. Thank God nobody was hurt or killed.

I love they have developed the attenuator with sound since his retirement.

As Corey and Chad stated, they know if they hear that; they are going to be hit and hopefully not seriously injured.

My thoughts and prayers go out to each of them who work on dangerous jobs like that in the paint trucks As well as Filling cracks in the roads from the winter.

I was also the secretary for the Ames maintenance residency for 13 winters/years.

So I would have to type up personal injury reports from things like this happening.

SLOW DOWN AND PAY ATTENTION TO HIGHWAY EMPLOYEES IN LIME GREEN CLOTHING so their lives can be saved and they can go home to their loved ones daily.

Thank you from a former Iowa DOT spouse knowing the dangers say face daily.

Jack and I were each 30 year DOT employees until our retirements.

Stay safe road crews! I know the audible attenuators work. I hope ALL moving maintenance and construction operations can be equipped with these safety devices.

Great article! It helped me better understand the dangers that the workers on the road are facing and measures taken to mitigate them.

I'd like to share an additional feature that could be added as another aid to draw driver's attention to work zone. Typically vehicles doing the work are moving at a much slower speed than traffic. In Eastern Europe slow moving vehicles are required to have a sign on the back indicating the speed limit for them. I propose adding a large "speed limit" sign to the back of attenuator that specifies the average speed that the work crew is moving with. Yellow speed limit sign (like we see on exit ramps from highways) would draw attention of the drivers and give them a good idea on how much they need to slow down to match the speed of working vehicles. As DOT set a goal of having zero fatalities in work zones I am hoping that my suggestion can be helpful in achieving this goal.

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