ENVIRONMENT ORIENTED TRANSPORT POLICIES AND TRANSIT NETWORK DESIGN

摘要

Following the most recent directives promoted by European Community, main cities have begun to renew transit fleet with electrical and alternative cleaned fuel vehicles to achieve reductions in emissions. The possibility of allocating low and zero emission vehicles (LEV and ZEV, respectively) in the network is taken into account in this paper introducing a method for solving the transit network design problem in a multimodal, demand elastic urban context dealing with the impacts deriving from transportation vehicle emissions. The mathematical formulation as an optimization problem explicitly takes into account the relationship between demand modal split, level of transit service and transport externalities related to the introduction of a limited number of green vehicles in the transit fleet. The design criteria are addressed to develop an intensive rather than extensive transit network in order to improve environmental quality, transport efficiency, integration among direct routes and effective transfer points that strongly affect service quality and riderships. The solving procedure consists of a set of heuristics, which includes a first routine for route generation and a genetic algorithm for finding a sub-optimal set of routes with the associated frequencies and the allocation of green vehicles.