A Comparison of the Multiple Dispatch and M/M/c Priority Queueing Models of Police Patrol

In many cities, a substantial fraction of calls for police service require more than one patrol car. We compare Green's multiple dispatch queueing model to several M/M/c-based approximations for multiple car dispatching that are obtained by adjusting the parameters. We found that none of the approximate models yields consistently reliable results under a broad range of conditions. The best approximations are produced by reducing the actual number of servers. Increasing the call rate gives the worst results.