Effect of Policy Mix on Urban Road Network Capacity Assessment Considering Shared Mobility

In the context of the trend for green travel, the emergence of shared mobility, represented by e-hailing and ridesharing, provides behavioral richness for travelers. Consequently, the authorities that devote themselves to balancing supply and demand in multimodal networks are concerned with incorporating shared mobility into transportation planning and formulating reasonable policy measures. A novel capacity model incorporating a policy mix is developed here as a bi-level programming problem in which the lower-level model is a combined modal split and traffic assignment considering elastic demand (CMSTA-ED) problem, while the upper-level model maximizes the origin-destination (OD) demand multiplier. Integrating the capacity model (the effectiveness index) with social welfare (the implementability index) can account for the synergy, facilitation, and potential contradiction of policy mixes. Numerical experiments validate the characteristics of shared mobility as a supplement to poorly performing public transit under its poor performance. It also examines the policy mix between a public-transit priority subsidy, parking charging, and the shared-mobility subsidy to discover the positive coordination that any individual policy cannot satisfy. This study provides implementable insights for further formulating rational policy-mix strategies on shared mobility to promote the sustainable usage of shared mobility.