Modeling an Elastic-Demand Bimodal Transport Network with Park-and-Ride Trips

This paper presents a network equilibrium formulation for modeling commuters' travel choices in a bimodal transport system with park-and-ride (P&R) trips while the total demand is elastic to the congestion level of the network. A super-network approach is adopted in the proposed model. It is assumed that commuters' trips are categorized into two types, auto mode only and a combined mode with both auto and transit modes. The former is referred to as the pure mode trip and the latter as the P&R mode trip. The proposed model simultaneously considers the commuter's choice of the pure mode versus the P&R mode, the choice of parking location for the pure mode, the choice of transfer point for the P&R mode, as well as the route choice for each mode. The demand elasticity of transport system, the capacity constraints of transport facilities, and the congestion interaction throughout the super-network are also explicitly incorporated into the proposed model. The results of the numerical experiment show the following key findings: (ⅰ) traditional parking/P&R models may overestimate or underestimate travel demand distribution over network; (ⅱ) parking/P&R, transit scheduling, and carpooling schemes bring significant impacts on commuters' travel behavior and network performance; and (ⅲ) different transport policies may be to some extent mutually substituted.