Transport is a service, usually accompanied by large physical objects. Physical products are measured by their consistency, their closeness to a specification or a norm. Services are, almost by definition, always different, as circumstances and the state of the people concerned are always changing. Thus with a service, there is no norm. Measuring a mode of transports conformity to an engineering specification is a measurement of its performance, not its quality. Thus, quality of transport (or any other) service is its closeness to the requirements specified by the customer, or the end user. For a physical object, the customer is the specifying engineer, for transport it is the traveller. Similarly, the requirements concerned are those areas that are important to the consumer, not what the supplier, commissioning agent or regulator think are important. Marketeers use a concept known as the Zone of Tolerance, which represents the gap between the level of service that a customer desires and the level of service they will tolerate. Complex mixtures of circumstances, social, physical and psychological factors influence these levels, but the levels can be measured (indirectly) without resort to the reasons. Empirical qualitative research on 230 adults showed that Zone of Tolerance in transport varied not only according to the type of journey wanted but also in anticipation of the mode of transport to be used (i.e. people raised and lowered their expectations according to mode). Assessment of modes as well allowed a direct comparison of mode supply with Zones of Tolerance, showing the journey quality for specific journeys. Aeroplanes, for example, had a high level of requirement, and a high level of performance, whereas Metros had low expectation yet barely adequate performance. Taxis had a very narrow gap between desire and acceptability levels, suggesting they are seen as very functional modes, with very little variation in tolerance.
Abstract