The heterogeneity of vehicle classes and their lane-free movement are the unique characteristics of the mixed traffic conditions in several developing countries. Modelling and controlling such a traffic system is challenging since most well-established traffic flow models and control strategies are developed for homogeneous lane-based traffic. The complex driving behaviour and the inter-modal impedance in mixed traffic networks result in suboptimal throughput, increased delay, and environmental and safety concerns.
The present study systematically identifies the system characteristics suitable for modelling and develops link cost and capacity functions for mixed traffic based on traffic flow theory to incorporate the effect of traffic signals and the composite fundamental diagram parameters to represent the mixed traffic interactions. It is found that the proposed link cost and capacity functions perform well under different traffic compositions and are significantly better than the traditional models for mixed traffic networks. Next, field measurement methods and multi-linear regression models with traffic composition as the explanatory variables are presented to estimate saturation flow, jam density, and wave speed in mixed traffic conditions. The comparison shows that the proposed models outperform the existing multi-class model in estimating the composite fundamental diagram parameters for mixed traffic. Later, the study proposes a mathematical programming framework to develop a bi-objective formulation of optimal routing of single-class vehicle segregation in mixed traffic. Optimal routes for the waste management trucks through the mixed traffic is determined considering the trade-off across the competing objectives of aesthetic cost and public exposure. The evaluation using a case study that shows that the proposed single class segregation model gives a better trade-off solution accounting for network geometry, link characteristics, vehicular demand, travel time, etc. and the stakeholders can prioritise their options for routing according to the budget available giving importance to the trade-off between the two costs. Finally, the seminar concludes with extensions of the formulation for the multi-class segregation problem.