Taxis as a Recourse Option for Ridesharing Services

Ridesharing services commonly offered at airports and to mobility-impaired persons exist worldwide. Unlike operators in conventional public transit, ridesharing operators maintain flexible routes and schedules that are used in providing door-to-door service. These routes and schedules are typically created by using the assumption of perfect foresight about future travel times. In practice, however, vehicles may encounter traffic congestion, be delayed because of road work or an accident, or even break down. Thus, the routes and schedules may adhere to quality-of-service constraints in planning when perfect conditions are assumed, but operationally they often violate such constraints. This paper investigates the effectiveness of routes and schedules created under a deterministic travel time assumption. The paper evaluates practical solutions that force the schedules to include excess slack. Finally, the paper proposes and assesses a recourse option for use in actual operations of assigning to taxis those passengers who are likely to be picked up late. The evaluation was completed on a real-world case study in Richmond, Virginia.