Travel Demand Model - OKI

OKI/MVRPC Travel Demand Model – Version 6.05.6 Trip BalancingStep 16 applies the OKI trip attraction models to the entire consolidated region, and balancestotal attractions to productions. In the course of calibrating and validating the trip distributionand highway assignment models, it was determined that this method tended to overestimate thetrip interchanges between the OKI and MVRPC regions. The most likely reason is that the OKItrip attraction models do not fully apply to the MVRPC region. Original trip attraction models forMVRPC could not be estimated, due to lack of data. Instead, attraction scale factors wereintroduced to allow control over the allocation of attractions between the two regions. Thesescale factors were estimated jointly with the production scale factors by adjusting the modelregional volume and VMT estimates to the observed volume and VMT. Special attention was paidto the screenlines, in particular those at or near the border between the two regions. The finalattraction factors are shown in Table 5.8. Note that the overall effect of these factors is todecrease the attractiveness of the OKI region for work trips, and to decrease attractiveness ofthe MVRPC region for HBO trips.Table 5-8 HBW and HBO Attraction Scale FactorsRegionScale FactorHBW HBOOKI 0.85 0.90MVRPC 1.12 0.755.7 Step16 Batch, Control and Parameter FilesThe Step16 parameter file, ST1601.inp, was modified to add a new parameter to the tripgeneration program: the highest internal zone number (NIZ). Previously this parameter wasinternally calculated by assuming that all zones with no households and no employment wereexternal zones. This is no longer the case, and thus it was necessary to read this parameter oninput. ST1601.inp also specifies an additional output file (see Section 5.8). The Step16 batchfile, Step16.bat, was modified so that it now uses the new version of the executable program,ST160160.exe. The modified control and batch files are listed in Appendix A. Additional inputfiles to the Step16 program are listed in Table 5.9 below.Additional parameters were added to control the balancing of trip attractions to productions,identified in the control file as SCALHBW and SCALHBO. See Appendix B for a listing of thesefactors.Trip Generation - Trip Generation 20