ABSTRACT
Fixed stops and Hail stops are among the possible mode of service used in intra-urban transit. Under the fixed stop service, vehicles stop to load or unload passengers at designated points only. For the hail stop service vehicles stop to load and/or unload at any point along the route on demand by patrons. The relative performance of fixed stop and hail stop services have been evaluated and compared. The objective that guided the comparison is that of minimisation of the total system cost. Models for total system costs per passenger are set up and the optimum headways that best satisfy the chosen objectives are determined for each service. Numerical values are specified for models' variables. Sensitivity analyses have been used to isolate the parameters affecting the total system costs and optimum headways. The most significant elements affecting both functions are demand on the route, length of the route, value of out-of-vehicle time and the normal operating cost. Results from the sensitivity analyses were then used to generate guidelines for comparing the two modes of service under consideration and isolate the conditions under which one service is more appropriate for adoption than the other. On the latter, two hypotheses were advanced, which are then used to derive a general methodology for comparing the modes of service. Highlight from the proposed methodology is that the demand, value of time, the route length and the operating cost are needed to be compared for both services. In the situations where demand is low, value of time high, the route short and operating cost low the hail stop may well be better. It was found out that for a 24 seater vehicle capacity that hail stop was better at nearly all demands considered. The effect of vehicle size on the modes of service were examined; larger vehicles are more appropriate to be used for the fixed stop service and smaller capacity vehicles for the hail stops service. Also examined is the effect of changing 0-D pattern on the services. Hail stop was found to be more sensitive to changes in the 0-D pattern. On this basis it is recommended that where demand is low enough, hail stop operation should provide collective and distributive service i.e moving patron to high activity areas(e.g CBD) and from CBD to residential locations. While the fixed stop is more suitable to serve as line haul service between important major activity centres in urban areas.