In order to plan its time-tables, a road transport corporation needs to have reliable information on the lead-factors on various bus-trips that are currently operated. Existing information does not permit determination of load-factors on segments of trips, but provide only over-all trip-wise load-factors. Such load-factors need to distinguish between local and through traffic. The conceptual separation of these types of traffic is discussed. An approach to estimating segment load-factors is described which includes development of results for simultaneous confidence intervals for the estimates.