IMPROVED ROAD SAFETY THROUGH REAL-TIME ADVANCE WARNING SYSTEMS

Despite significant improvements during the past 20 years, traffic collisions continue to be the biggest transportation safety problem in Canada. Investments in Intelligent Transportation Systems (ITS), including real-time Advance Warning Systems, can help improve safety by informing drivers of unexpected traffic conditions ahead, encouraging them to adjust their vehicle speed, and thereby helping to prevent avoidable collisions. This paper will examine two case studies were Advance Warning Systems were installed by the Ontario Ministry of Transportation (MTO) on identified freeway sections in Southern Ontario to address current and anticipated traffic safety problems. In the first case study, a comprehensive traffic study was undertaken to address high collision rates associated with unexpectedly long, standing truck queues on the Queen Elizabeth Way and Highway 405 approaches to the Niagara Region border crossings. The traffic study proposed that a Queue-end Warning System (QWS), designed to inform drivers approaching the end of a vehicle queue, be implemented on these two highway approaches. For each border approach, inductive loop detectors and hybrid dynamic warning systems were install at locations strategically determined to optimize the coverage of the highway approaches. The QWS continuously monitors traffic flows in each of the approach roadway lanes and once a queue is detected, the system automatically activates the warning signs upstream of the end of the queue to warn drivers of the vehicle queue ahead and to be prepared to stop. In the second case study, as part of the MTO’s highway-widening projects, a single high occupancy vehicle (HOV) lane and bypass tunnel were constructed along Highway 404 southbound to westbound Highway 401. The short tunnel (i.e., which is approximately 90 m long) is the end point of the HOV lane, and has a curve to the right that leads traffic to the Highway 401 Westbound Collector. While the tunnel was built to current Ministry standards, the perception of motorists may be distorted or distracted due to the fact that the traffic is travelling from a wide-open roadway to a short enclosed tunnel with a curve, compounded by different light transitions through the tunnel. In order to enhance the safety of motorists approaching the tunnel, an Advanced Warning System (AWS) was deployed to provide advance notice of anticipated ramp queues that can build from the recurring congestion on Highway 401. The system seamlessly integrates detector loop and video image processing vehicle detector technologies to achieve fast and accurate incident and queue detection in all traffic flow conditions. Two dynamic message signs located upstream of the tunnel entrance provide advance appropriate warning messages to drivers. This paper describes the deployment of these QWS and AWS systems, and provides examples of how ITS can be used to dynamically detect unexpectedly slow vehicles and queues and provide accurate and timely advance warning to drivers of unexpected traffic conditions ahead, encouraging them to adjust their vehicle speed, and thereby reducing rear-end collisions and improving motorist safety