V ehicle scheduling is the process of assigning vehicles to a set of predetermined trips with fixed starting and ending times, while minimizing capital and operating costs. This paper considers modeling, algorithmic, and computational aspects of the polynomially solvable case in which there is a single depot and vehicles are identical. A quasiassignment formulation is reviewed and an alternative asymmetric assignment formulation is given. The main contributions of the paper are a new two-phase approach which is valid in the case of a special cost structure, an auction algorithm for the quasiassignment problem, a core-oriented approach, and an extensive computational study. New algorithms are compared with the most successful algorithms for the vehicle-scheduling problem, using both randomly generated and real-life data. The new algorithms show a significant performance improvement with respect to computation time. Such improvement can, for example, be very important when this particular vehicle-scheduling problem appears as a subproblem in more complex vehicle-and crew-scheduling problems.The single-depot vehicle-scheduling problem (SDVSP) is defined as follows: Given a depot and a set of trips with fixed starting and ending times, and given the travelling times between all pairs of locations, find a feasible minimum-cost schedule such that (1) each trip is assigned to a vehicle, and (2) each vehicle performs a feasible sequence of trips. All the vehicles are supposed to be identical. A schedule for a vehicle is composed of vehicle blocks, where each block is a departure from the depot, the service of a feasible sequence of trips, and the return to the depot. The cost function is usually a combination of vehicle capital (fixed) and operational (variable) cost. The SDVSP is well known to be solvable in polynomial time.Overviews of algorithms and applications for the SDVSP and some of its extensions can be found in Daduna and Paixão (1995) and in Desrosiers et al. (1995). Several network-flow-type algorithms have been proposed for the SDVSP in the literature. In particular, the SDVSP has been formulated as a linear assignment problem, a transportation problem, a minimum-cost flow problem, a quasiassignment problem, and a matching problem. We briefly discuss the most relevant algorithms. Let n be the number of trips to be covered by vehicles. Paixão and Branco (1987) propose an O n 3 quasiassignment algorithm which is specially designed for the SDVSP. Computational results indicate that this approach significantly outperforms approaches based on transportation and linear-assignment models. The quasiassignment algorithm is a modified version of the Hungarian algorithm for the linear assignment problem, including the improvements proposed by Jonker and Volgenant (1986). An extension of this algorithm can also deal with a fixed number of vehicles (see Paixão and Branco 1988). Dell'Amico (1989) (see also Dell'Amico et al. 1993) proposes an O n 3 successive shortest-path algorithm for the SDVSP, which uses the initializ...