NCJ Number
92993
Date Published
1982
Length
147 pages
Annotation
Strategies for Wide Area Patrol (SWAP) is a new model developed and tested using data and advice from the Washtenaw County (Michigan) Sheriff Department. The model proves useful for evaluating rural patrol allocation policies and the cost-effectiveness of providing contract police patrol services to unincorporated areas or small towns as well as for maintaining effective patrols when policing agency resources are reduced.
Abstract
In those areas where travel time is a significant component in servicing a call, urban based models do not sufficiently represent reality. SWAP explicitly incorporates travel time by representing the patrol system in terms of a Markov process model, using a travel state for each region. When applied to Washtenaw County, primary measures of interest were the fraction of time a unit is on patrol in each township and the mean response times to emergency and routine calls. Results indicate that two patrol cars substantially reduced average response times to all types of calls, when compared to using a single car. A third car in one of the 12 townships substantially reduced average response time in that region. A fourth car led to further reductions in all mean response times. The model successively computes the probability that each car is busy and modifies call rates to account for calls that cannot be handled by cars from their region of origin. The model iterates until these probabilities converge. This approach avoids solving a combinationally large problem for multiple cars and has performed efficiently in practice. Tables, appendixes, and 18 references are supplied.