Transit dwell time

Dwell time can be a significant component of the overall travel time for transit. In San Francisco, about half of the bus travel time is taken up by the servicing of passengers or by the bus either pulling in or out of a stop.

Dwell time to service passengers is often represented in one of three ways:

  1. Not explicitly included: this is an appropriate simplification when the dwell time is either not of much consequence to the total travel time (i.e. an express or low-ridership route), or if it is predictable and already included in the in-vehicle travel time (this is common for rail)
  2. Included as a constant value: this is an appropriate simplification if the dwell time is fairly even throughout the route and ridership is evenly distributed.
  3. Calculated as a constant value (pull-out/pull-in time) plus a function of boardings and alightings and other variables that may affect dwell time such as crowding levels.

Based on research at SFCTA, it may be appropriate to segment the above techniques and parameters by mode, vehicle and route type (i.e. an urban articulated bus will have different boarding and alighting times than a van or one-door vehicle)

One also may want to consider the application of policies such as bus bulbs, all-door boarding, and low-floor vehicles to the dwell time.