In-vehicle warnings show promise for improving work-zone safety
Work zones can be dangerous for both drivers and the work crew—but Roadway Safety Institute (RSI) researchers are working on innovative ways to lessen these risks and lower the rate of work-zone crashes. In a new study, an RSI research team investigated the potential advantages and possible disadvantages of vehicle-to-infrastructure (V2I) in-vehicle messages to communicate to drivers.
“When we started this project, we saw a potential for drivers to become more aware and responsive to hazards within the work-zone by presenting the information directly to them through in-vehicle messaging technologies,” says Nichole Morris, director of the University of Minnesota’s HumanFIRST Laboratory, who led the project. “We also wanted to assess the extent to which this type of messaging could lead to driver distraction, as numerous studies have demonstrated the hazards of distracted driving, particularly from interacting with on-board technologies.”
One bridging technology to provide V2I in advance of future original equipment manufacturer (OEM) capabilities could be a smartphone. To investigate the possibilities, the researchers began with multiple literature reviews to illustrate the crash risks imposed by work zones and the factors that exacerbate these risks, along with the ideal design guidelines for any in-vehicle messaging system. Next, they conducted a survey to uncover driver attitudes in Minnesota toward work-zone safety, smartphone use, and the potential for receiving messages through in-vehicle technologies.
“Our survey found that a significant number of drivers use their smartphone while driving—for navigation, talking, and even texting—and that they place them in a variety of locations throughout the vehicle, rarely in a mount,” says Morris. The survey revealed positive attitudes toward the use of a V2I work-zone messaging system but concern over its distraction potential. The researchers also found that many drivers distrust the accuracy of roadside signs for work zones and were receptive to using an electronic messaging system, Morris says.
Following the survey, researchers designed the in-vehicle messages and conducted a simulated driving study in the HumanFIRST Lab to test the effectiveness of the messaging system on driving safety. During the driving simulation, participants drove through two different types of work zones three times, each with different work-zone events and messaging interfaces. These included a portable roadside message sign, a smartphone presenting only audio messages, and a smartphone presenting audio-visual messages; the smartphones were either mounted on the dashboard or placed in the passenger seat to reflect real-world conditions. During the drives, researchers recorded measures of driving performance such as vehicle control, event recall, mental workload, user-friendliness, and eye-tracking metrics.
After analyzing the driving simulation data, researchers found that drivers using either type of in-vehicle messaging performed better than they did with the roadside warning signs. Furthermore, drivers had better vehicle control and reported significantly less mental workload, better usability, and greater work-zone-event recall with the in-vehicle warnings than with the roadside signs.
“Using eye-tracking technology, we can see that participants took their gaze off the road less often with the in-vehicle messages, as drivers had to look over to read the roadside signs in order to understand the messages,” says Morris. “In addition, the positive effects of in-vehicle messages appear to be elevated for the more difficult drive, suggesting that in-vehicle messages were helpful for more challenging roadway conditions.”
The study produced two key findings. First, if in-vehicle messages are delivered in a controlled and driving-relevant manner, there appeared to be no effect of distraction, and driving performance improved. Second, placement of the messaging interface did not appear to be a significant factor for driving performance when the messages contained an audio component. Researchers hope to continue this work by field testing in-vehicle message systems and exploring possible avenues for broad implementation.