During the design stage, the Ministry identified safety concerns about the forthcoming Highway 404 High-Occupancy Vehicle (HOV) tunnel being introduced. Based on the design, motorists entering the tunnel at design speed will have adequate line-of-sight for lane blockages or queues. However, motorists violating the speed restrictions pose a heightened risk in terms of potential collisions. Consideration was given to alternative tunnel geometries that would inherently improve safety however, these alternatives were far too costly with little return in improved safety. An Advance Warning System (AWS) was proposed. The AWS is an automated system designed to improve tunnel safety, reduce the potential for both primary and secondary collisions, and to reduce incident response times. The Advanced Warning System was successfully commissioned with Ontario’s official HOV lane opening on December 13, 2005 and is fully meeting and exceeding the original goals for improved motorist safety and incident management. The warning messages provided on the signs has exceeded the degree of safety of a multi-million dollar geometric realignment, however at a fraction of the cost. This system is the first of its kind in North America and will set the new standard for exceptionally safe and efficient freeways in Ontario.
