Modelling Urban Bus Service and Passenger Reliability

Reliability of public transport systems has been considered critically important by public transport users, operators and the government. Lack of reliability in public transport results in uncertainty and delays aggravating anxiety and discomfort for the passengers and increases costs due to lost mileage and lower fleet utilisation for the operators. The government emphasises a reliable bus-service in order to ensure its competitiveness to car use such that it results in modal shift. Though reliability is of significance to a range of actors such as the bus operators and the passengers, its interpretations vary across different groups. For example, quality of service identified by the demand-oriented indicators, the travellers, is systematically different from what the supply-based quality indicators show. Reliability, as a measure of quality of service, is related to the operational characteristics of the public transport system. Passenger’s wait time, on the other hand, is much more sensitive to schedule reliability than to service frequency.