摘要

Location and allocation of emergency response units are assumed to be interdependent in the incident management system. System costs will be excessive if delay regarding allocating decisions is ignored when locating response units. This paper presents an integrated method to solve location and allocation problem of emergency vehicles on freeways. The principle is to begin with a location phase for managing initial incidents and to progress through an allocation phase for managing the stochastic occurrence of next incidents. Previous studies used the frequency of independent incidents and ignored scenarios in which two incidents occurred within proximal regions and intervals. The proposed analytical model relaxes the structural assumptions of Poisson process (independent increments) and incorporates evolution of primary and secondary incident probabilities over time. Interdependent ERUs location-allocation problem is solved by taking stochastic information of future incidents explicitly into account with lookahead. The mathematical model overcomes several limiting assumptions of the previous models, such as no waiting time, returning rule to original depot, and fixed depot. The initial nonlinear stochastic model is linearized. The temporal locations flexible with lookahead are compared with current practice that locates units in depots based on Poisson theory. An efficient heuristic algorithm is implemented to deal with time-consuming process of a large-scale problem in real time.

  • 出版日期2016-9