The TransCAD version of OCTAM 3.1 travel demand model was used to build the customized TransCAD version of the OCTAM 3.1 model for these CSMP studies. The original TransCAD version of the OCTAM model only had a highway traffic assignment module. Through the understanding of the original GISDK codes from Caliper Corp., a few new components were added to the enhanced OCTAM model. The new modules include select link analysis, subarea analysis, OD estimation, and output data display. In addition, we also converted OCTAM’s trip generation module to TransCAD and enabled the possibility to use different types of volume delay functions on different types of roadway facilities. For example, the BPR functions can be applied to freeway segments and the default Akcelik functions can be applied to arterials.

Besides the improvement on the OCTAM GUI, the geometries for all study corridors were updated to the latest condition. We also enabled a feature to add penalties to some turns barred in the real world in order for the model to be realistic. Moreover, most CSMP study corridors allowed us to prepare a well balanced datasets that were used in the calibration of the focused models for each study corridor. Potentially, these dataset can be applied to the whole OCTAM model to make it more accurate.