APPLICATION OF THE INCREMENTAL TRAVEL MODELING APPROACH IN BOISE

Ada County and the city of Boise, Idaho, are updating their urban travel model as part of a regional transportation study. An incremental travel modeling approach, a derivative of the four-step travel modeling approach, and geographic information system software are being used. The incremental travel models developed for Ada County use the projected changes in land use, socioeconomic, and travel data to forecast differences in trip table matrices from the base to future years. The differences are applied to the base year trip tables to produce future year trip tables. The advantages of this approach over traditional four-step modeling include the data needs for forecasting are not as intensive because of the incremental nature of the approach; and the accuracy is improved by forecasting differences from well calibrated base conditions. This approach is a valid alternative to traditional travel demand models because of the high quality multidimensional base year trip tables created from available data.