Table 2 Assessment of the theoretical basis for assuming diminishing returns

Frequency

Yes. An additional service (increased frequency) has a smaller effect on the average waiting times (assuming random arrival) the larger the existing number of services.

Number of service providers

Yes. An additional service provider has a smaller effect on the intensity of competition the larger the existing number of services. For most destinations, there is only one service provider. The introduction of a second service provider leads to competition on that route, the effect of a third competitor is small.

Minimum number of intermediate stops

No. An intermediate stop adds transit time. There is no reason to assume this effect will be less important the larger the number of intermediate stops.