For the computation of departure time choice, one needs information
about the trip times as a function of different departure times.
[[Different possibilities are discussed in Sec. .]] The
implementation that we present here is the arguably simplest method,
but it has some caveats for large scale scenarios. [[This will also be
discussed in Sec.
. ]]
The idea is that one parses the events file, and for each origin, each
destination, and each time bin one averages the trip times. This is
similar to how the router treats link travel time information. That
is, if an individual departs (events flag 6), then this information is
stored away somewhere. If the same individual arrives (events flag
0), then the departure time and departure location are retrieved, and
the travel time is added by the time bin for the departure time for
the corresponding OD pair. Once the complete events file is parsed,
the sums are divided to the number of entries as was done for the link
travel times. If you assume that you have time bins,
origins,
and
destinations, then this results in
entries.
Note that you have to invent some method to generate OD travel times for time bins for which you have no information.