Evaluating HOV Plans and Priorities - The Case of Expressways in the GTA

The proportion of High-Occupancy Vehicle (HOV) commuting trips in the Greater Toronto Area has been declining over recent years. In an effort to reverse this decline and make more efficient use of the available infrastructure, the Ministry of Transportation of Ontario has begun to implement HOV lanes on the 400-series highway system. The implementation of HOV lanes on portions of Highway 403 and 404 in late 2005 met with substantial success. In support of the planning and prioritization of future HOV lane implementation, the Ministry conducted a study focused on the area to the east of Highway 427, to forecast HOV use of potential future HOV network components. HOV forecasting is not a standardized tool in the transportation planning toolbox. Different approaches have been attempted with varying levels of success. This paper is a useful addition to the literature on the subject in that it discusses some of the key issues encountered and describes the development and adaptation of models and methods to address these issues. Issues discussed include making maximum use of available data, model validation with before-and-after data, and the integration of macroscopic travel demand modeling with microsimulation to combine the strengths of both approaches.