Speed Notification System Warns Drivers Approaching Urban Work Zones

  • A variable message sign, part of the SWZSN, displays the warning "Slow Traffic Ahead" in a construction zone.
  • Speed detection sensors were installed on poles every half-mile through a new highway construction work zone.
Status:  Complete
Report Date:  06/04/2019


Queue warning systems are effective on rural highway work zones but not as effective in complex urban highway work zones, where traffic slowdowns and other disruptions are less predictable and more frequent. Drivers often brake suddenly and risk rear-end collisions when encountering unexpected traffic backups. Researchers evaluated MnDOT's Smart Work Zone Speed Notification system over two construction seasons in a complex urban highway construction project. The system was designed to detect changes in traffic speed near or in work zones, and then through an algorithm generate a message on a variable message sign to provide drivers with real-time information about slowed traffic ahead. Messages such as "35 MPH 1 Mile Ahead" proved effective in changing drivers' behavior, influencing them to slow in time to avoid sudden braking or collisions. The system has already been deployed in two more urban highway construction work zones.

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