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98 be used to derive relevant averages for comparable trips in for estimating internal capture, these would be combined the region. It is important to use vehicle-occupancy rates that as residential. reflect travel during the analysis period. Do not use daily When applying the internal capture estimation methodol- vehicle-occupancy rates. ogy, use the percentages from the third and fourth columns of sub Table 7.1 and sub Table 7.2 within Tables 105 and 106. Each sub table contains both A.M. and P.M. peak-hour data. If Step 3C: Enter Mode Split for MXD a local survey has been conducted using data collection and This is the mode split for the MXD. It does not apply to the compilation procedures described in this report, the result- base trip generation rates. Percentages of trips by transit and ing internal capture percentages may be used. Users are cau- non-motorized mode (e.g., walk, bike) may be different by tioned that data gathered in a method different than the data direction. Enter the percent of directional trips by each mode collection methods described in this report may not be appli- for each land use in Table 103, sub Table 2-A for the A.M. peak cable and could produce inaccurate internal capture estimates. hour and corresponding sub Table 2-P of Worksheet 2 for the For land uses other than the six classifications provided P.M. peak hour. The product of Step 3B is an estimate of the herein, users should assume no internal capture (unless com- number of person-trips in vehicles entering and exiting each parable survey data for other land uses are provided). The of the mixed-use development land uses. It is important to percentages in Tables 105 and 106 are not applicable to other use mode of access distributions that reflect travel to and land uses. They are also only for the weekday A.M. and P.M. from the MXD during the analysis period, not daily. peak periods and should not be used for other periods. In some cases, review agencies may set policies to limit the Step 3D: Compute Person Trips percent internal capture they will permit to be applied based on their own justifications. Such limitations would represent Using the vehicle trips entered in Table 103, sub Table 1-A, agency policy to use what they consider more conservative trip and vehicle occupancies entered in sub Table 2-A, compute generation estimates (e.g., to avoid the possibility of under- directional trip generation for each land use: estimating trip generation) and are not to be confused with the findings of this project. Person trips = vehicle trips vehicle occupancy. Enter the person trips in Table 104, sub Table 7-A for A.M. Step 4B: Apply Proximity Adjustment Factors trips. There are corresponding tables in Worksheet 2 for com- (P.M. Peak Period Only) puting P.M. estimates. The unconstrained internal capture values presented in Tables 105 and 106 represent rates to be expected between Step 4: Estimate the Unconstrained Internal land use pairs that are not constrained by proximity. As some Capture Rates for All Land Use Pairs at land use pairs become farther apart, the unconstrained inter- the Site nal capture rates will decline. This step accounts for the spe- In this step, unconstrained internal capture rates that are cific proximity characteristics of the MXD. appropriate for the subject development site are determined. Proximity adjustment factors are presented below for This determination begins with the base internal capture rates only the land use pairs for which the available data clearly documented in this research (described in Step 4A); the rates demonstrates a direct relationship between proximity and are then modified to account for specific proximity character- internal capture rate. These are comprised of only P.M. peak- istics of the subject site (described in Step 4B). period trips; no proximity adjustments are available for the A.M. peak period: Step 4A: Estimate Base Internal Capture Rates From all land uses to residential and applicable only to the Internal trip capture rates are provided for land use pairs trip origin end; involving the following generic land use classifications: From office to retail or restaurant, applicable at both ori- office, retail, restaurant, residential, hotel, and cinema. Trip gin and destination trip ends; and generation estimates were made in Step 3 for specific types From residential to retail or restaurant, applicable at both of land uses. For estimating internal capture, land use classifi- origin and destination trip ends. cations should be combined into the above general categories before continuing into the estimation process--for example, These factors are only applicable during the P.M. peak for a development containing apartments and townhouses, hour. If a land use pair is not included in the above list, use