Reducing variation not function: Lessons from applied route bus design research

Individual bus operators specify vehicles in line with their own unique requirements. Collectively, diversity across vehicle specifications increases costs and lead time and decreases quality in local bus manufacture, paradoxically having negative consequences for the very function that specifications were intended to improve. The vehicle specifications are driven by functional requirements and are therefore difficult to reconcile with manufacturing by simply reducing them. This research set out to develop bus designs balancing user and manufacturer needs. Investigation found that specification diversity results from bus operators determining designs to meet their requirements – resulting in a raft of solutions to the same or similar problems. Two interventions to this situation were formulated; that a higher-specification product could offer equal or better function to bus operators while being of standardised manufacture; and that a system of modular design could be implemented where specification differences were functionally justified. These approaches were tested in the design, manufacture and implementation of a new driver’s area for route buses. It was found to meet the functional requirements of several Australian bus operators while streamlining manufacture. It resulted in a definitive design strategy for the development of better public transport vehicles.