CASE STUDY: BUS FLEET REPLACEMENT.

Parallel replacement analysis is concerned with determining minimum cost replacement schedules for a group of assets that are economically interdependent and operate in parallel. That is, keep and replace decisions are required for each asset among a group of assets over a specified horizon. The assets are economically linked through economies of scale or budgeting constraints. One application of parallel replacement analysis is fleet replacement. We recently studied the operations, including fleet replacement policies, for a city transit bus operator in Europe. Key factors in their replacement decisions included the ability to choose from multiple manufacturers, purchase price, and government regulations. We explore these and other factors, by solving a heterogeneous replacement problem with fixed costs, budgeting constraints, and demand constraints. Through extensive sensitivity analysis we analyze the impact of various parameters on decisions, in terms of the choice of replacement assets, as well as the optimal time to retain assets. Additionally, we provide motivation for future research in this application area, which is important for many cities. [ABSTRACT FROM AUTHOR]