Field Evaluation of the Effectiveness of a Public Transportation Priority System (PTPS) under Real-World Traffic Conditions

This paper reports a field evaluation of a public transportation priority system on a mixed tram and bus corridor in Hiroshima, Japan. We designed and deployed a wireless architecture using ITS Connect that provides drivers with the current signal state and the remaining time until the next signal change, and sends priority requests, either green extensions or red shortenings, to the signal controller. The prototype consisted of an on-board unit, a roadside device, and virtual beacons that detected approaching vehicles at a signalized intersection. We verified three core functions derived from predefined use cases: passage detection, execution of priority control, and in-vehicle display of system status. On 12 March 2025, twenty-seven test runs were conducted between 09:30 and 16:00. The roadside device recorded every virtual-beacon passage. Driver information was provided in all runs. Priority control was executed when the time from cycle start to beacon passage was up to approximately 78 s, with adjustments from −10 to +10 s. Negative values indicate red-phase shortening, and positive values indicate green-phase extension. The evaluation confirmed functional viability and identified implementation issues, including the lack of pre-execution notification to drivers, the alignment between map data and satellite-based positioning, and the timing of the in-vehicle display.