A work zone queue warning system at the I-70/I-57 interchange reduced queuing crashes by 14 percent and injury crashes by 11 percent.

Experience mitigating work zone crashes in Effingham, Illinois.

Date Posted

Mitigating Work Zone Safety and Mobility Challenges through Intelligent Transportation Systems: Case Studies

Summary Information

The objective of this study was to evaluate the effectiveness of a work zone queue warning system installed to improve safety during reconstruction on the I-70/I-57 interchange in Effingham, Illinois. The system used portable dynamic message signs (DMS) mounted on solar powered trailers equipped with traffic detectors and cameras to monitor traffic conditions and warn drivers of developing queues. Using cellular communications, DMS trailers located 10 to 12 miles upstream of the work zone were integrated into a wireless command and control system to provide drivers with real-time information on traffic queues and opportunities to select alternate routes if needed.

An evaluation was conducted to assess impacts on queues and delays, and end-of-queue crashes with and without the system installed. The construction project occurred between December 2010 and October 2012. The following functions and features were deployed.

  • Capability to operate automatically on a continuous (24/7) basis.
  • 25 portable dynamic message signs (DMS) capable of remote control via a central computer base station.
  • 25 portable traffic sensors linked to the central base stations.
  • 20 remote video cameras linked to the central base station.
  • One central base station with appropriate software and either wireless or dedicated phone line communications to link with the traffic management system components.
  • A password protected project website (with color coded map display) that project personnel could use to monitor conditions and check on operational status of the system components.

The Illinois DOT found that with the system in place travelers experienced fewer crashes, including fewer end-of-queue crashes.
  • Between 2010 (prior to system implementation) and 2011 (after system implementation) researchers saw nearly a 14 percent decrease in queuing crashes, and an 11 percent reduction in injury crashes, despite a 52 percent increase in the number of days when temporary lane closures were implemented during the evaluation.
Although it was not certain whether the queuing frequencies and conditions between the two years were similar, the data collected suggested positive benefits.
Goal Areas