Using buses as probes for neighbor links travel time estimation in an urban network

Using transit vehicles as probes offers a number of advantages as they cover large parts of urban networks and the equipment required for data collection is usually already installed by transit operators. Travel time estimation using buses as probes is usually limited to specific transit routes. In this research, the potential of using bus travel time data to estimate auto travel times of neighbor (nearby) links is investigated. The main research hypothesis is that travel times of nearby links are strongly correlated as they are subject to similar traffic conditions. Two clues are used for travel time estimation; historical travel time data of the link itself and real-time bus data from neighbor links. A case study was presented using a microsimulation model of downtown Vancouver. The model was calibrated and validated using real-life traffic volumes and travel time data. Neighbor links travel time estimation accuracy using bus probes data was assessed using the Mean Absolute Percentage Error (MAPE), the value of which was 15.4%. The method was proven to be useful to estimate travel time on links that do not have real-time travel time data while having strong travel time correlation with neighboring links.