Work-zone intrusions—in which vehicles breach the boundaries of roadway construction or maintenance operations—are a serious safety concern. From 2005 to 2010, 733 road workers were killed in work zones in the United States, with about half struck by motorists, according to the Federal Highway Administration. Motorists themselves are also injured or killed by intrusion crashes.
To address this safety risk, it’s critical to understand what contributes to work-zone intrusions. Yet little is known because the methods and standards for capturing data around these events are not well established.
To fill this gap, researchers with the U of M’s HumanFIRST Laboratory created a system for road crew workers to report work-zone intrusions. The research was sponsored by the Minnesota Department of Transportation (MnDOT) and the Minnesota Local Road Research Board.
The data collected by the system could be used to examine risk factors, provide feedback to workers and MnDOT, and provide an empirical basis for future policy recommendations to the state.
HumanFIRST research associate Curtis Craig says that in aiming to make the system comprehensive yet efficient and user friendly, the researchers needed to first learn about the work zone crews—what they knew, the context of their work, and how they carried it out. “And we wanted to make sure we were testing [the system] in ways that reflect how they would use it in the real world,” Craig says.
The researchers interviewed workers across Minnesota in both urban and rural settings. They found that workers understood an intrusion as a vehicle entering the area cordoned off by cones, but they felt it was practical to report an intrusion only when there was an actual increased risk to the workers onsite. “Whenever there were high risks, they were more likely to want to report it,” Craig says.
During testing of the initial design, researchers asked potential users to input either a researcher-generated intrusion scenario or an actual one from their experience—“and they all had experiences that they were scared by or that were very memorable to them,” Craig says.
Workers and supervisors were asked to “think aloud” as they interacted with the interface and were timed as they completed the reports. “We wanted to make sure it wasn’t taking too much time out of their day. And we wanted to get a feeling for how usable the interface was,” Craig says.
The second phase of testing showed that workers struggled with whether they would use the report to record minor intrusions they personally didn’t feel at risk for, Craig says. “Like a car coming in to and out of the work zone and knocking over a few cones. They could just go put the cones back up and get on with their workday. So that was an ongoing tension between what we wanted, which was to get as much data as possible, and what they felt they needed to provide,” he says.
As a result, the researchers revised the earlier reporting logic by splitting it into an immediate “minor” report and a more comprehensive “major” report for higher-risk incidents. Users also tested different modes of the interface with a laptop, a tablet, and a paper form.
Work crew supervisors noted that the final version of the system should provide a clear explanation and rationale, which would help them motivate their crews to reliably report intrusions, Craig says. The success of the reporting system will depend not only on workers using it, he adds, but on a sustained dialogue between the users and the administrators of the system, adding that this engagement will help users feel “they’re in the process of improving safety culture.”
According to Craig, MnDOT staff are currently reviewing ways in which the intrusion reporting system could be integrated into the agency’s infrastructure.