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between Home-to-Work and Work-to-Home. The Home-Based-Other trips were <br />divided into trips between Home-to-Other and Other-to-Home. By splitting the HBW <br />and HBO trip purposes into their components; this eliminated the possibility of a <br />problem of excessive trips between households. In addition, a Truck trip purpose was <br />added to allow for the explicit generation and tracking of truck trips. Therefore six trip <br />types were used: <br />• Home to Work (HW) trips, <br />• Work to Home (WH) trips, <br />• Home to Other (HO) trips, <br />• Other to Home (OH) trips, and <br />• Non-Home-Based (NHB) trips <br />• Truck trips <br />PTV America developed the following trip generation factors for use in the model. The <br />base trip generation rates were taken from ITE's Trip Generation Report. Factors used to <br />separate the trips into the six purposes and origins-destinations were from NCHRP <br />reports 187 and 365 and experience by PTV America with other studies. The trip <br />generation process used percentage control totals that correspond to data in NCHRP <br />365 for similar sized areas. <br />Trip generation rates are set at values during the beginning calibration simulations. As <br />the calibration process is conducted, adjustments are made to the rates to better reflect <br />the known (or base-year) travel conditions. Generated trips are compared with traffic <br />count volumes and modified to match these volumes as closely as possible. During the <br />process the residential and agricultural land uses were disaggregated for better <br />definition of actual trip making characteristics. The total trips generated were adjusted <br />for the three main county areas based upon regression analysis and observation of the <br />behavior of the model with these adjustments. The allocations of the SFDU, MFDU, and <br />AGFM units to the territories <br />During the update of the model, the trip rates were refined for use in Kittitas County. <br />This involved making incremental changes and comparing the results with the traffic <br />counts in the areas throughout Kittitas County. Trip rates were revised as necessary to <br />achieve improvement of the modeled volumes within Kittitas County. Table 6 presents <br />the final trip generation rates used for the weekday evening peak hour model. Note that <br />Kittitas County, Washington Transportation Model-May 2009 Page30