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96 The following description of the computational process ITE Trip Generation Database: The MXD should not has been put into the form of these spreadsheets, and there already be covered in the ITE trip generation database as is an accompanying Excel spreadsheet workbook to auto- reported in the latest edition of Trip Generation (2). Cur- mate the computations. It is intended that the spreadsheet be rent ITE land use classifications that already account for used to perform computations. The spreadsheet workbook is internal trip-making include shopping center, office park explained for the A.M. street peak hour and consists of the four with retail, office building with ground floor retail or spreadsheets shown in Tables 103 through 106. The P.M. street onsite cafeteria, and hotel with limited retail and restau- peak-hour estimate is prepared identically. The estimator-- rant space. either automated or manual--was designed to have a cover Time Period for Analysis: The internal capture rates con- sheet that contains all input and output of interest, with look- tained in this methodology cover the weekday A.M. and P.M. up data and intermediate computations on the subsequent peak periods for adjacent street traffic. Weekday peak period spreadsheets. The description that follows uses the spreadsheet internal capture rates are not appropriate for estimating as an example. weekend internal capture--or weekday midday internal capture--or daily internal capture unless survey data for Step 1: Determine Whether the Methodology those periods become available. Is Appropriate for Your Application The procedure should only be used for estimating internal Step 2: Define the Pertinent capture at an MXD that has characteristics resembling the Site Characteristics sites from which the internal capture rates have been derived. In this step, the following data describing pertinent site This step screens/eliminates sites for which the procedure is characteristics are assembled: appropriate. The specific land uses in the mixed-use site in sufficient Development Type: The MXD should be a single, physi- detail so that vehicle or person trip generation can be esti- cally and functionally integrated development on a single mated for each individual land use (described in Steps 2A block or a group of contiguous blocks with three or more and 2B); and revenue-producing uses, with internal pedestrian and vehic- Building proximity for each pair of land uses (described in ular connectivity, and with shared parking among some or Step 2B). all uses. The site should have sufficient parking supply to meet demand although the most convenient parking may The source of much of this information is a proposed site sometimes fill during peak periods. Development Location: The MXD should be downtown plan, if one exists. If a site plan is not available, assumptions fringe, general urban, or suburban. It should not be located must be made about general site layout, individual land uses, either within or adjacent to a central business district (CBD). sharing of parking, and the internal pedestrian circulation Development Size: The MXD should have at least system. 100,000 sq ft of building space within an overall acreage of up to roughly 300 acres. The MXD can be a single site, Step 2A: Identify Land Uses a block, or a district or neighborhood (with multiple inter- connected or interactive blocks within a defined bound- Identify specific land use components of the MXD ary); however, this procedure should not be used for a and assign them into the six classifications--office, retail, SAC composed of different adjacent, but not directly con- restaurant, residential, cinema, and hotel--covered by the nected, land uses. estimation procedure. Any component land uses that do Land Use Mix: The MXD should consist of a combination not fit into those six classifications or are too unique to be of at least three of the following uses: retail, restaurant, considered normal for a classification should be kept sepa- office, residential, hotel, and cinema. Internal capture for rate. If in doubt, keep a land use separate from the six listed land uses beyond these six should be considered to be zero classifications. (unless comparable survey data for other land uses are Define the land use components in as much detail as pos- provided) because there are no supporting data from which sible. The greatest detail will allow for greatest precision in to derive an appropriate percentage. In addition, if a sub- trip-generation estimates. The internal capture relationships stantial portion of the land use at a mixed-use site is outside quantified in this methodology are provided at the aggregated these six land uses, the reported internal capture rates might land use level. It is important to separate the retail and restau- not be appropriate. rant uses in this step because they exhibit different internal cap-