[en] One element in the Physical Protection of Nuclear Material in Transit Program is a determination of the number of local law enforcement agency (LLEA) officers available to respond to an attack upon a special nuclear material (SNM) carrying convoy. A computer model, COPS, has been developed at Sandia Laboratories to address this problem. Its purposes are to help identify to the SNM shipper areas along a route which may have relatively low police coverage and to aid in the comparison of alternate routes to the same location. Data bases used in COPS include population data from the Bureau of Census and police data published by the FBI. Police are assumed to be distributed in proportion to the population, with adjustable weighting factors. Example results illustrating the model's capabilities are presented for two routes between Los Angeles, CA, and Denver, CO, and for two routes between Columbia, SC, and Syracuse, NY. The estimated police distribution at points along the route is presented. Police availability as a function of time is modeled based on the time-dependent characteristics of a trip. An example demonstrating the effects of jurisdictional restrictions on the size of the response force is given. Alternate routes between two locations are compared by means of cumulative plots