OPTIMAL DIMENSIONS OF BUS SERVICE ZONES

Multiple period optimization models arc developed that may be applied to several types of bus transit systems including feeder routes to transfer terminals, radial routes to activity centers. and zonal service operations. Decision variables including zone size, route length. route spacing, and service headway are optimized in closed form either independently or jointly. Although the service headways may be separately optimized for each time period, the route lengths and spacings must normally be optimized at unique values over all time periods, while varying with location. Effects of system parameters, such as demand density. operating cost and speed, value of time, and line-haul distance on the optimal route characteristics are identified. Guidelines for designing bus-service networks are provided based on the analytic results obtained.