Evaluating dispatching consequences of automatic vehicle location in emergency services

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Abstract

Automatic vehicle location (AVL) systems present to the dispatcher of emergency response units (e.g., police cars, ambulances) the estimated real time locations of units within his service area. Building on a recently developed hypercube queuing model, this paper presents a Markov process model for computing the operating characteristics of the radio-dispatched fleet operating under a policy that dispatches the closest available unit to each call for service (implying use of a perfect resolution AVL system). The model accommodates a realistic description of the service area and rather general spatial deployment policies for units.

In implementing the model for efficient computer execution, the focus is on computation and storage minimizing procedures for generating the state-to-state Markov transition rates. One useful technique involves the effective application of a recently developed backward regenerative unit-step tour of the hypercube. The algorithmic procedures generalize to computer solutions of MIMIN queuing systems with distinguishable servers, different customer classes, and a cost structure for assigning servers (who may be in one of several “postures”) to customers of each class.

The paper concludes with a realistic nine-unit police example that indicates the general ways in which AVL dispatching improves (and degrades) system performance.

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Cited by (0)

Richard C. Larson is Associate Professor of Urban Studies and Electrical Engineering, Massachusetts Institute of Technology. He holds a B.S., M.S. and Ph.D. in electrical engineering, with specialization in operations research, from M.I.T. Professor Larson's papers have appeared in The Journal of Computers and Operations Research, Operations Research, Management Science, Journal of Criminal Justice, IEEE Transactions on Systems Science and Cybernetics, IEEE Transactions on Vehicular Technology, Journal of Urban Analysis, Sloan Management Review, Evaluation, and Journal of Research on Crime and Delinquency. He is author of a book Urban Police Patrol Analysis, M.I.T. Press, 1972, which was awarded the 1972 Lanchester Prize of ORSA. He has served as a member of the Science and Technology Task Force of the President's Commission on Law Enforcement and Administration of Criminal Justice (1966–1967) and the Police Advisory Panel of the National Commission on Productivity (1973).

Evelyn A. Frank, now a consultant in Paris, France, received her Masters Degree in Operations Research from the Massachusetts Institute of Technology in 1976. She received the S.B. degree from Universidad de los Andes (Bogota, Colombia) in 1973. At the Universidad de los Andes she held the position of lecturer on Computer Programming and Research Fellow in Planning.

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