ALIAGES: A System for the Assignment of Bus Routes to Garages

Abstract

Most large transit companies operate several garages, and must face the problem of deciding which garages will adequately serve bus routes. Several costs and operational constraints must be taken into account in the decision process. Since terminology varies between transit operators, we first define some basic terms.

The objective of the system described is to assign vehicle trips independently or by lines to the various garages of a transit company in order to minimize both the number of vehicles required and the deadhead costs. The system can also be used to study the optimal location of new garages. A heuristic procedure is proposed for solving this problem because of the variety of operational constraints which must be respected These constraints include the requirement for trips of a subset of routes to be assigned to a specific garage, to only one garage among a given subset, or to be split amongst no more than two or three garages. Constraints on the minimum and maximum number of buses assigned to a garage for peak and off-peak services are also imposed. The problem and solution methods are discussed in the context of the S. T. C. U.M., (the Montreal Transit Commission) where the system will be implemented.