Texas Detection Control System

MTO is currently undertaking a pilot project to test a new detection control system to improve the safety of rural high speed signalized intersections and reduce the incidence of red light infractions. Current advanced warning systems have not effectively addressed vehicles just entering or within the dilemma zone when the traffic light turns to amber, resulting in high-speed trucks running the red light. With participation from the Texas Transportation Institute (TTI), MTO installed the Texas Detection Control System (TDCS) at intersections in Northwest Region and Eastern Region in an effort to address these concerns and evaluate the effectiveness of this unique technology.

Interrelated detection-control system diagram

Operational and safety concerns were identified at rural high-speed signalized intersections in Ontario. The ministry utilizes Advanced Warning Flashers to provide advanced information on the state of the traffic signals ahead to approaching drivers. Additional detection systems such as Long Distance Detection and Double Long Distance Detection system, which provide increased dilemma zone protection have not deterred red light running. Furthermore, existing detection systems would terminate the signal without regard to the number or type of vehicles approaching or within the dilemma zone.

TTI developed an Intelligent Detection Control System that enhanced MTOs Double Long Distance Detection System. The TDCS monitors cars and trucks approaching rural high-speed signalized intersections and determines the optimal time to end the signal phase. The system is able to classify a vehicle as it approaches a signalized intersection and determines the vehicles speed, the occupied lane and the vehicle type.

Continuous communication is held between the detection-control system components (Figure 1). The vehicle detection system detects vehicles speed, classification, and location via speed trap loops located in advance of the dilemma zone and sends a signal to an industrial computer running the algorithms which in turn communicates to the signal controller. The system is able to predict a dilemma zone for each vehicle approaching the intersection and predict whether the vehicle will proceed or be able to stop safely at the intersection, adjusting the signal display times accordingly. Customized software and hardware in the signal controller cabinet (Figure 2) will either end the green light before the driver enters the dilemma zone or hold green the green light to allow drivers to clear the dilemma zone before turning red. The system will not end a green signal with trucks in the dilemma zone but will relax to allow one car within the dilemma zone.

Previous field trials by TTI and Texas DOT found the TDCS reduced general red light violation by 53% and reduced truck red light violations a further 80%. In spring 2006, MTO trial-tested the system at locations that would significantly benefit safety and operations. The TDCS was installed on Highway 17 at Round Lake Road and Doran Road in Pembroke (Eastern Region) and Highway 11/17 at Oliver Road in Thunder bay (Northwestern Region). Dr. Karl Zimmerman of the TTI together with regional representatives from MTO participated in the installation. The study undertaking the evaluation of the detection system was awarded to Lake Head University under the Highway Infrastructure Innovation Funding Program (HIIFP). A final report is expected for August 2007 on the results of the Ontario in-field evaluation. Look to upcoming issues of Road Talk for comprehensive coverage.