Headway-based Selective Priority to Buses

This paper addresses the problem of bunching of buses and how it may be counter-acted. An algorithm is presented for providing selective priority to buses at traffic signals according to their headways, the highest levels of priority being given to those buses with the highest headways, i.e. those buses which are running late or falling behind the bus in front.Alternative selective priority strategies are evaluated in terms of their effects on bus journey time regularity, bus delay and general traffic delay. A simulation model SPLIT (Selective Priority for Late buses Implemented at Traffic signals) has been developed to investigate the performance of different priority strategies. The paper describes the details of the model, including bus stop dwell times and overlapping bus services, and compares results obtained from the model for a number of different priority strategies.This work was driven by the keen interest in bus priority applications in London within the EC DGVII project INCOME.