Socio-Economic assessment framework for replacing bus lines with DRT services

Abstract

Recently, new forms of mobility services have emerged (i.e. carsharing, micromobility, TNCs, etc.), having impacts on cities development and particularly on existing travel modes performances. For instance, it has been observed, especially in US and European metropolitan cities, that DRT (inc. Uber, Lyft, Lime) are often associated to the increase of road congestion and the decline of transit ridership. In peri-urban and rural areas, on the other hand, the diffusion of DRT is limited, even if the provided transit modes (i.e. bus) are usually inefficient and expensive for the society. This paper is devoted to investigating the socioeconomic potential of replacing buses (noted CPT for Conventional Pubic Transport) by DRT (Demand Responsive Transport) in peri-urban areas as complementary services to the existing transit network. It is based on a bi-level modelling approach: (1) at the first level, we propose an agent-based model, which describes movements of on-demand vehicles and assigns them to passengers in order to maximize the vehicle’s utility function. The traffic equilibrium is obtained for demand that is function of the generalized cost only. (2) The second model proposes a socio-economic optimization, which determines supply conditions (fleet size and fare) that maximize the gain for the operator, for the users and for the society. An application is then proposed for a real case in Paris metropolitan area by replacing CPT line with DRT service. Results suggest that social welfare is maximized for fleets of 20 to 30 vehicles and fares of 2 to 3€ per trip.