Designing capacity and service level at ferry crossings

This paper first deduces how the transport capacity over a ferry crossing, measured by the number of passenger car equivalents, depends on the length of the crossing, the ferries' size, their speed, their efficiency of boarding and alighting them. Such calculations are essential in order to evaluate whether the ferry material used at a service has sufficient capacity fulfilling national quality standards like meeting required transport demand during the opening hours and a stated minimum probability for users to board their desired departure. Second, the paper derives a model that shows how welfare optimal frequency at a crossing depends on its level of traffic, ferry users' waiting time costs, the cost structure of ferry operations and the length of the crossing. The model demonstrates in a clear way the influences of crossing - and ferry fleet characteristics on optimal frequency. Using Norwegian data for ferry users' waiting time costs and for the costs of operating ferry transport services, the model's results indicate that the authorities recommend to low frequency, in particular at high traffic services. It is also emphasised that the length of the crossing has great impact on optimal frequency; optimal frequency at long crossings is less than a half compared to short crossings for all levels of traffic. Lastly, the model shows that it is more serious from a welfare perspective to undersupply frequency with X units than to oversupply it with X units.