In the transit assignment, modules 5.11 and 5.31, it has always been possible
to break down the trip impedance into its main components and store them
in separate matrices for later use. Thus, the following matrices can, if
desired, be computed during a transit assignment:
-- weighted total trip time
-- in-vehicle time
-- auxiliary transit time
-- waiting time
-- boarding time
-- number of boardings
While these components cover the needs of most applications, there are situations in which it would be very useful to have a break-up of some of these components by mode or mode group. This is especially the case when there are several transit modes, possibly operated by independent transit companies. Such a break-up can also be useful in the calibration and use of mode choice models which use mode specific variables, or when studying the effect of different fare structures.
Starting with Release 4.0, it is possible to compute some of the transit trip component matrices for a subset of the active modes used in the assignment. The subset of transit modes applies to the matrices for in-vehicle time and number of boardings, while the subset of auxiliary transit modes applies to the auxiliary time component matrix. If any of these matrices are requested when preparing the assignment in module 5.11, the question
Compute auxiliary time, invehicle time and number of boardings on a subset of modes only?follows immediately the specification of the active transit modes. If a subset is requested, the user is then asked to specify it, using the usual mode selection dialog.
With this new feature, it is possible to compute the trip components for any desired mode or mode group. If several sub-components are needed, the assignment is repeated once for every mode subset.
This implementation retains full flexibility and does not penalize the normal use of the transit assignment by sacrificing efficiency.
Note that the new question mentioned above may require a small adjustment of macros which invoke module 5.11 to prepare a transit assignment.