A stochastic model for a vehicle in a dial-a-ride system

We consider a stochastic model for a system which can serve nn customers concurrently, and each accepted and departing customer generates a service interruption. The proposed model describes a single vehicle in a dial-a-ride transport system and is closely related to Erlang’s loss system. We give closed-form expressions for the blocking probability, the acceptance rate, and the mean sojourn time, which are all shown to be insensitive with respect to the forms of the distributions defining the workload and interruption durations.