Bandwidth optimisation and parameter analysis at two adjacent intersections based on set operations

Abstract

Bandwidth-based models are widely used for traffic signal coordination. Maxband-based integer linear programming is the most popular and practical method of obtaining the maximum bandwidth solution and researchers have been making continuous improvements to it for decades. However, the impacts of the parameters of the model determine (i) whether the parameter needs to be optimised and (ii) whether the optimisation results are strictly optimal, and have not yet been well explained. To analyse specifically the impacts of the relevant parameters on bandwidth, this study focuses on two adjacent intersections to establish a general mathematical description, including the parameters cycle, split, travel time, phase sequence, and offset, and further characterises the bandwidth versus relative offset relationship. The authors analyse the bandwidth solutions obtained with different relative offsets and the effects of parameters on the through-band. The results of the proposed model provide a reasonable interpretation of parameter optimisation strategies in bandwidth-based models, reveal the possibility for better offset transitioning, and promote awareness of the issues involved in applying Maxband-based models.