OPTIMIZATION OF GRID TRANSIT SYSTEM IN HETEROGENEOUS URBAN-ENVIRONMENT

Current analytic models for optimizing urban transit systems tend to s acrifice geographic realism and detail in order to obtain their soluti ons. The model presented hare shows how an optimization approach can b e successful without oversimplifying the spatial characteristics and d emand patterns of urban areas. This model is designed to optimize a gr id transit system in a heterogeneous urban environment whose demand an d supply characteristics may vary arbitrarily among adjacent zones. Ne twork characteristics (route and station locations) and operating head ways are found that minimize the total cost, including supplier and us er costs. Irregular many-to-many demand patterns, zonal variations in route costs, and vehicle capacity constraints are considered in a sequ ential optimization process.