Scriba, Tracy, and David Register
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The Illinois DOT used ITS during reconstruction of a 40-mile section of Interstate 55 including the Lake Springfield Bridge. Reconstruction of the bridge involved closing the southbound span and diverting southbound traffic onto the northbound span, and then reversing the process once work on the southbound span was complete. To minimize congestion and improve safety in the work zone, the DOT deployed a Real Time Traffic Control System (RTTCS) from February 2001 to May 2002. The RTTCS consisted of 17 portable dynamic message signs (DMSs), 8 portable vehicle detectors, and 4 portable closed circuit television (CCTV) cameras linked to a central computer via a wireless communication system. The field components were solar powered.

The DMSs displayed a variety of messages including delay information, lane closure advisories, and the number of citations for moving violations. The CCTV camera images were used to confirm traffic and incident data. The central computer monitored traffic flow data from the vehicle detectors, calculated delay at each detector location, automatically displayed preprogrammed messages on DMSs, updated a real-time traffic condition map on the project website, and provided congestion and incident alerts for Illinois DOT staff via email or pager.

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The Illinois Department of Transportation (IDOT) chose to deploy ITS to support work zone operations for a major bridge and highway reconstruction project on Interstate 55. A Real Time Traffic Control System (RTTCS) was used, which included portable dynamic message signs (DMSs), portable traffic sensors, and portable closed-circuit television (CCTV) cameras linked via wireless communications to a central workstation. The RTTCS system covered the southbound and northbound approaches to the work zone for a total of 40 miles. The system was used from February of 2001 to May of 2002, monitoring traffic along I-55, automatically generating messages on the DMSs based on predefined thresholds, providing data for a real-time congestion map displayed on IDOT's website, and transmitting congestion/incident detection alerts for IDOT staff.

Other Reference Number
Report No. FHWA-HOP-04-018
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Federal Highway Administration, U.S. DOT
Source ID
Intelligent Transportation Systems in Work Zones: A Case Study - Real Time Work Zone Traffic Control System
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