Knowledge Resources

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 DMS units 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.

The reconstruction 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.

SYSTEM COSTS

Total system costs were estimated at $1.545 million.

• Initial mobilization and deployment of the system components: $1.5 million.
• Traffic management system operations and maintenance: $1,800 per month for 25 months.

At the conclusion of the project the system was intended to remain operational to support three additional projects in the area over the next several years. Budget estimates included the following.

• Initial mobilization of additional sensors, signs, cameras: $78,750.
• Traffic management system operations and maintenance: $29,767 per month for 25 months.

IDOT noted that it can be difficult to know in advance how much equipment will be needed and where it should be installed. Depending on site conditions additional devices may be required or equipment may need to be moved.