This page provides a rundown of the trip generation rates used in step 4 of the West Station area study. Trips are generated by households, jobs, schools, etc. Household characteristics are important determinants of how many trips are likely to be made by each household for different travel purposes. Four key household characteristics were used for the trip generation analysis: household size, household income, vehicle ownership, and number of workers.
Base year and forecast year estimates of households specify the number of households in respective subgroups along each of these dimensions for all model area TAZs. For example, there are estimates for each TAZ specifying the number of one-person households, two-person households, three-person households, and four-or-more person households; and separate estimates specifying the number of zero-car households, one-car, two-car, and three-or-more-car households.
Trip generation rates, however, are specified at a more detailed level, such that these dimensions need to be combined. Each household’s size, income, number of vehicles, and number of workers is needed to model trip generation. The accessibility-based model includes an iterative proportional fitting (IPF) module to cross-classify households, estimating the number of households by detailed combinations of characteristics for each zone.
The detailed trip generation rates can be explored in the tabs below. For “non-home” trip generators (jobs, school enrollments, e.g.), the columns reflecting household dimensions have the value “Non-home”. Use the filters above each column to search and sort the tables. Note that rates are specified for impossible household types - like one-person households with two workers - but these are precluded in the cross-classification process.
The table below presents trip generation rates for person trip productions by travel purpose:
Note that NHB trip productions are estimated based on household characteristics, but as non-home-based trips, they do not begin or end at the household location. The household characteristics inform the magnitude of NHB trip productions, and these are spatially redistributed to match the locations for NHB attractions.
In addition to households characteristics, trip generation is also influenced by land use context. Three land use categories are specified in the regional travel demand model, and their influence on trip generation rates is reflected in the table. The land use categories break down as follows:
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The table below presents trip generation rates for person trip attractions by travel purpose:
Note that households have attraction potential for the HBO purpose, reflecting social travel. There is no land use factor in estimating person trip attractions. Key non-home categories include:
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