A Comprehensive Solution for Urban Traffic Congestion Dilemmas: Allocating Roadspace to Public Transport

Transport planners are continually seeking ways in which to balance the often conflicting needs for their limited road space. There is trend towards the reallocation of roadspace to on-road public transport due to its effectiveness in people movement and wider environmental benefits (road diet). However reallocating roadspace can be a delicate task since it is often at the times of highest demands that space must be taken away from one mode to benefit another. Transport planners are not assisted by the techniques they have available to manage this issue. Traditional warrants for provision of facilities such as bus lanes only consider the relative people moving abilities of alternative modes. Generally these methods only examine the average travel time impacts on people. Yet in practice one of the main benefits of public transport priority is improved service reliability. The benefits of improved reliability and the wider environmental benefits of these schemes are not a part of traditional approaches to determine if road space reallocation is appropriate. This paper describes a new method for assessing the impact of reallocating roadspace to public transport. The presented approach would identify the optimal combination of transit exclusive lanes, considering the benefits of all network users. The presented method involves the effects of shift in modal split, private car route choice, and transit route choice. The problem is formulated in form of a bi-level optimization with integer variables. A solution algorithm based on a decomposition method is proposed. The presented approach is applied to an example network and results are discussed.