Design and operation of feeder systems in the era of automated and electric buses

This paper evaluates the impact of vehicle automation and electrification on the applicability of fixed routes and door-to-door services to supply a feeder transit solution in suburban areas. These technologies will modify the current cost structure of the bus system depending on how mature they are, reducing operating costs and increasing capital costs. By means of a continuum approximation model, we evaluate the performance for users and agency of the two feeder strategies in different scenarios of technological development. The results show that automation has the main impact on the applicability between the two feeder alternatives while the effects of electrification are considerably smaller. The future applicability of door-to-door trips reaches wider ranges, although this change is especially significant under some circumstances of technology, service area and users. The expansion of this range is relevant in case the automated bus is mature enough (high reduction of operating cost and low vehicle acquisition price), the areas are small, the trips are short and the value of time is high. However, the results reveal that fixed routes will remain a competitive feeder solution in a wide range of scenarios. We identify that the demand density threshold grows sharply in front of any reduction of agency costs once its value is around 200–300 pax/km2-h. Therefore, flexible services will gain applicability especially in environments that allow reaching this threshold.