Automation of sound warning to increase safety in Iowa work zones

Crashed attenuatorMaking sure you are paying attention when you’re driving near those working on the road is essential to helping you avoid a crash and keeping everyone in the area safe, the main priority of the Iowa Department of Transportation. Last year we told you about a program that added a loud noise to a piece of equipment known as an attenuator. An attenuator is typically a trailer pulled by a large truck. Their purpose is to block oncoming traffic from entering a work zone and they are designed to take a hit instead of a worker if a driver happens to not be paying attention. While we’ve seen success with adding sound to this equipment, the next step to keeping you safer on the road is to automate the triggering of the noise.

How is automation expected to help?

Currently, the audible warnings coming from our attenuators are activated by an operator sitting in the truck ahead of the device. When the operator feels that a driver is coming too close and there is the danger of a crash, the operator uses a switch to activate the sound, hopefully getting the attention of the driver. This audible warning 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.

New equipmentTo take some of the burden off of the operator, we are working with Iowa State University and equipment vendors to develop research and add cameras and sensors to the attenuators that would automatically trigger the warning noise when a vehicle gets too close or is coming toward the work zone too quickly. The operator would always have the option to manually trigger the alarm if needed.

What information do the cameras and sensors detect?

The cameras will capture video of traffic and will record the movement and speed of vehicles traveling in the area. This is the information the system needs to identify when to sound the alarm if a vehicle is about to encroach on the work zone. The system’s artificial intelligence can “learn” the optimal time to sound the alarm using the data.

“The vendor is monitoring the cameras live when they are in use. This will allow them to make adjustments,” said John Hart, director of the Iowa DOT’s Maintenance Bureau. “As for our operators, this system will run in the background, but they will still be able Camera view to take over manually if they need to. They will still have control.”

Hart says cameras and sensors are currently installed on the attenuator used by the central Iowa paint crew. This fall he anticipates the Iowa DOT will have these capabilities installed on equipment used by our other five district paint crew attenuators and three other vehicles.

Once the cold weather hits and the paint crews shut down for the winter, all the data that has been collected will be analyzed and the systems adjusted to start back up in April 2023. Hart said, “Not only will we be looking at how well the cameras and sensors captured information and responded to the situations we’ll look at the equipment itself and how it held up to the punishment that comes with being in a work zone.”


What else will this research provide?

Hart said, “Teaming up with Iowa State, we found a vendor that typically designs missile defense systems to detect moving objects. As far as we can tell, this research project is the first of its kind in the United States. It uses cameras and sensors in a configuration similar to how a human eye detects the distance to watch for traffic that may be in danger of crashing into a work zone.”

He continued, “By putting cameras and sensors on the back of the attenuator, we hope to not only trigger the audible warning more consistently but also be able to capture more information on driver behavior,” said Hart. “We have never been able to ‘see’ how people react behind the attenuator before, so having this information could not only help this process but could give us valuable insight into safer ways to set up the work zones.”

The impact on attenuators

Audible explainedEven though attenuators are designed to be crashed into, each hit takes its toll. The driver who hit the attenuator may be injured and the vehicle severely damaged. Our crews must deal with the psychological impact of a crash in their work zone. In addition, there is the cost and time lost when an attenuator has to be repaired or replaced.

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

Hi Bill - Yep, I'm still here!

Don't tell me - you are still working? I have sure enjoyed my last 20 yrs but I sure liked my job at the DOT! Bill Burns

Good question Kathleen. The sound is similar to a siren, but very distinct. It's designed to get your attention.

Will the sound scare a driver?

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