Does automated speed enforcement in work zones reduce distracted driving?

traffic road
Photo: iStock

Work zones are necessary—and often dangerous. Each year more than 100 road construction workers and 500 drivers are killed in highway work zones nationwide. Driver inattention contributes to approximately half of all work-zone crashes and worker strikes. 

Though there is consensus about the dangers of highway work zones, the path to reducing injuries and deaths in them is less clear. To help identify solutions to this persistent highway safety problem, U of M researchers investigated the impact of different types of speed enforcement methods on driver attention in work zones.

“Work zones are dangerous for many reasons,” says Nichole Morris, a research associate with the HumanFIRST Laboratory. “There are numerous factors drivers may not expect, such as lane closures and high traffic volumes. In addition, high-risk driving behaviors such as distraction, speeding, and aggressive driving make the problem worse.” 

The investigation examined enforcement methods currently used in Minnesota as well as the potential influence of automated speed enforcement (ASE). “Up to this point, little has been known about how ASE compares with other speed limit enhancements in terms of its impact on driver attention and distraction,” Morris explains.

The project, sponsored by the Minnesota Department of Transportation (MnDOT), used a high-tech driving simulator with eye-tracking technology to examine how drivers responded to four types of work-zone enforcement: control (no enforcement), police car present, dynamic “your speed” signs, and automated speed enforcement.

The test-subject drivers were asked to drive through a realistic simulated work zone on a divided Minnesota rural roadway while engaging in a secondary “distraction” task. The researchers then analyzed the results to determine whether drivers responded to the four types of speed limit enhancements differently with regard to speed limit compliance, safe following distances, crash rates, lane control, visual attention, and distraction seeking.

car simulator
Video recording of a test participant’s gaze through eye-tracking
glasses

“Overall, our results did not find that automated speed enforcement in itself strongly improves driver attention in work zones,” Morris says. “However, we did find some evidence that drivers heighten their visual attention with a combination of automated speed enforcement and dynamic speed display signs.”

In addition, researchers found the largest effects were among younger and older drivers, who tended to exceed the speed limit most often and varied their speed slightly based on the type of enforcement present. Middle-aged drivers exhibited the greatest speed control and tended to abide by the speed limit to the same extent regardless of the type of enforcement present. 

“Because younger and older drivers are the most at-risk groups for work-zone crashes, it is promising that they appear to be the most positively influenced by the combination of automated speed enforcement and dynamic speed display signs,” says Morris.

Ken Johnson, MnDOT’s state work-zone engineer, was the project manager. “While automated speed enforcement is currently not being considered legislatively, we needed to determine if this method would be distracting to motorists as they navigate the work zone,” he says. “The results indicate that automated speed enforcement neither improved driver attention nor distracted the driver. This is important to know as we don’t want to add to driver distraction in an area where they need to pay attention.”

More Information

Subscribe

Sign up to receive our Catalyst newsletter in your inbox twice every month.

Media Contact

Michael McCarthy
612-624-3645