Multiple leaders and their spatial orientations – An empirical approach in modelling vehicle-following behaviour under mixed traffic condition

Acceleration models are an integral part of microscopic traffic simulation models. Most of the established acceleration models in the literature have typically considered the response of a follower based on the stimulus from a single distinct leader in the front. But under weak lane disciplined conditions, it is common to observe multiple leaders ahead of a subject vehicle, thereby leading to multiple stimulus sources. To accommodate this condition, the study formulates longitudinal acceleration models when multiple leaders are present by modifying the conventional response-stimulus model. These models are developed based on trajectory data from which information is derived about the presence and positions of multiple leaders and their static and dynamic characteristics that influence the response of the follower. The response under multiple and single leader scenarios are evaluated. Further, the influence of the spatial orientation of leading vehicles in relation to the subject vehicle is also investigated. The differences in driving behaviour of the two major constituents in the mixed traffic stream considered, namely, two-wheeler (TW) and car are compared and contrasted under single and multiple leader scenarios.  The results show that the multiple leaders have a significant influence on the follower’s driving decisions that are distinct from the influence of single leader conditions. The proposed model enhances the realism of modelling scheme for mixed traffic behaviour with potential applications.