Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
49 Processing the Denver Travel Survey to Support Tour- Based Modeling Methods, Data, and Lessons Learned Erik E. Sabina, Denver Regional Council of Governments Gregory D. Erhardt, PB Consult Thomas F. Rossi, Cambridge Systematics, Inc. John Coil, Denver Regional Council of Governments The Denver Regional Council of Governments(DRCOG) is completely restructuring its regionalmodel. This effort began with the conduct, in the late 1990s, of the Travel Behavior Inventory (TBI) project, a suite of regional surveys, including a household travel survey. Following completion of the TBI, DRCOG began an Integrated Regional Model project, through which DRCOG is rebuilding the regional model on the basis of TBI data, in three phases: ⢠The refresh phase, a partial reestimation and full recalibration of DRCOGâs existing trip- based model (now complete); ⢠The vision phase, an evaluation of advanced mod- eling techniques and projects throughout North America and Europe (also complete); and ⢠The update phase, a project to build an integrated modeling system that includes components for both tour- based travel models and disaggregate land use models (under way). The paper is intended to aid modeling practitioners who are considering implementing advanced techniques such as tour- based models by describing the type of sur- vey DRCOG has used in its development of tour- based models, the techniques and assumptions used to struc- ture the survey data for that use, and trip and tour sta- tistics that the survey produced. SURVEY DESCRIPTION In the mid-1990s, when DRCOG began preparing for the TBI project, attempts at advanced modeling approaches were just beginning in practice in the nationâs metropoli- tan planning organizations. In the early phases of the TBI, DRCOG convened a panel of modeling practitioners to assess the current and possible near- future state of mod- eling practice in the country so that travel surveys could be designed to support those likely approaches. Data col- lected in 1997 included a home- interview survey, a brief onboard transit survey, a commercial vehicle survey, and an external station survey. The initial home- interview survey design was in an activity- based format; in this format, one record of data was collected for each activity in which the household members engaged. While Metro in Portland, Oregon, concluded that its activity- based survey was only mar- ginally more complex than a traditional trip- based sur- vey (1), respondents to the pilot survey in the Denver region found the format confusing. These findings led to development of a place format for the main survey that was based on a similar survey conducted in New York. The place survey asked respondents to describe the sequence of placesâ including the address of each, the kind of place each was (from a list of categories), and their activity at eachâ at which they stopped through the day. Respondents were asked to select primary and sec- ondary activities at the place from a list of 12 possibili- ties (or to write in âotherâ). The survey included a standard sample of 4,196 households as well as 677 households recruited through the onboard transit survey. Riders on 51 routes responded to the onboard transit survey, which collected basic information on the trip purpose and demographic characteristics of the rider. The survey was used primarily to identify transit riders who could be recruited to participate in the home- interview survey, and 677 households were recruited in