A Time-Responsive Approach for Sustainable and Flexible Mobility Services

The need for more flexible mobility solutions is introducing new requirements to meet more changing demands. Therefore, this paper proposes a heuristic approach for solving the dynamic Dial-a-Ride problem. In this problem, not all requests are known a priori, and a dynamic assignment procedure of new upcoming requests is needed to set up efficient vehicles’ routes. We propose a mixed-integer linear programming (MILP) model including constraints that extend its application to the dynamic case. The proposed solution method is based on a single vehicle problem decomposition where each vehicle route is computed using an exact approach, whilst requests are assigned to available vehicles according to a greedy insertion heuristic. We adapted a state-of-the-art instances’ set to the dynamic case randomly extracting requests to be served. Results reveal the usefulness of the proposed approach in evaluating the impact of stochasticity on service performances. Moreover, the obtained assignment computation times result compatible with responsiveness requirements of timely flexible services.