Traffic Platoon Dispersion Modeling on Arterial Streets

Calibration of Robertson’s Platoon Dispersion Model in Non-lane Based Mixed Traffic Operation

“…As a result, the microscopic behaviours of vehicles such as overtaking and lane changing behaviour observed in lane based traffic cannot be transferrable to non-lane based traffic as they are more likely to be different, which in turn will significantly affect the macroscopic behaviour of vehicles such as platoon dispersion [5]. Additionally, a few past studies [5,14] have investigated the effect of traffic volume on platoon dispersion factor (a) for lane based traffic system, but the finding may not be again directly applicable for non-lane based heterogeneous traffic as the freedom or constraints of manoeuvring in homogeneous traffic stream are likely to be different than that of heterogeneous non-lane based traffic. As a result, there still lies a gap in state of knowledge as to how non-lane based heterogeneous traffic will disperse and how traffic volume and composition affects such dispersion.…”

“…To demonstrate this fact, Bass and Lefebvre [15] calibrated platoon dispersion factor based on link travel time and traffic volume. Later, Manar and Bass [14] established a parabolic relation between traffic volumes and platoon dispersion factor (a). It was found that a increases as traffic volume increases and reaches its maximum value when volume becomes half of the roadway capacity.…”

“…Improper calibration of a and b may result an ineffective signal timing plan [29]. Manar and Bass showed that using a suggested value of a instead of using a locally calibrated value may result in additional delay for an arterial corridor [14]. Due to the significant impact of model parameters (a, b) on effective implementation of signal timing plan, several studies were carried out on calibration of these parameters, which could be categorised in two groups.…”

“…Further research on calibration of the model parameters identified the several other traffic state parameters such as traffic volume [15], volume to capacity ratio [5,14], mean and standard deviation of link travel time [30] as pertinent influencing factors. In present work, an empirical model is developed using non-linear regression technique to express platoon dispersion factor (a) as a function of vehicle composition, normalised flow, link travel time and modelling step size.…”

“…platoon dispersion factor (a) and travel time factor (b) [5]. Several studies pertaining to calibration of these two parameters have been reported in the literature for nearly homogenous traffic stream with disciplined lane behaviour [5,9,[13][14][15][16][17][18]. However, the traffic stream in developing countries such as India is highly heterogeneous and lane discipline is also absent [19].…”