Transit Path Building

Two basic options exist for modeling transit path choice in the travel forecasting process: (a) a detailed mode choice model and (b) deterministic procedures underlying transit multipath, path-building algorithms. These two options require different approaches to transit path building, mode choice, and transit assignment. Modeling decisions regarding transit path-building techniques and the amount of transit path choice incorporated into mode choice models directly affect the ability of travel models to consistently model mode choice and transit use. Options and their implications are presented for transit path building and mode choice. An analysis is presented of the success of alternate transit path-building techniques in reproducing known transit paths as reported by transit users in Denver, Colorado; analysis of several commonly used transit path-building validation techniques is also given. Suggestions are made for interface transit path choice and transit path building on the basis of the results of the empirical transit path-building tests. Two primary suggestions applicable to current planning processes are made. First, transit path choice should be performed in only one component of the forecasting process, such as transit path building or mode choice, to minimize inconsistencies in the modeling process. Second, disaggregate measures such as prediction success tables comparing modeled boardings to reported boardings for individual observations of transit trips should be compiled for validation of transit networks and transit path-building procedures.