Res 2001-197 - Laserfiche WebLink

Home Browse Search

model with particular emphasis on modeling trips in the San Marcos area. The Consultant will specify, develop and validate a separate mode choice model for SWTSU trips. The Consultant will retain the structure of the model, along with the coefficient and parameter estimates derived by CAMPO. The Consultant will implement the model as developed by CAMPO, but will validate it to observed aggregate mode shares in San Marcos. The Consultant will adjust the estimated coefficients until the model reproduces the target mode shares. The Consultant will prepare a final model where the set of coefficient values that deviate the least from the original CAMPO model University trip purpose derivations provide the best fit to observed aggregate mode shares. The Consultant will prepare and deliver to the City a technical memorandum in hard-copy, Microsoft Word, and Adobe.pdf formats outlining the structure and mathematical form of the mode choice models, including their derivation from the CAMPO model. The Consultant will thoroughly document the procedure for implementing the model in the TransCAD environment. 1.6.6 Re-Calibrate Trip Distribution. Change the structure of the trip distribution model in order to carry out trip distribution and mode choice by time of day. The Consultant will prepare and deliver to the City a technical memorandum in hard-copy, Microsoft Word and Adobe.pdf formats describing the new trip distribution process. The memorandum will also include a description of changes to the CAMPO model, with specifications for implementing the changes in the City model. 1.6.7 Model Validation. Develop a broader set of model validation targets which include: a) Trips per employee and trips per household by trip purpose; b) Trip length frequency distribution; c) Distribution of person trips attracted to special generators and major activity centers (such as the San Marcos CBD, SWTSU, and commuting to Austin); d) Auto occupancy; e) Transit and vehicle trips at the zone group level; f) Transit mode share by trip purpose and mode of access; g) Transit passenger volumes and travel times; and h) Statistical comparisons between observed and estimated values, such as root mean square error (IRMSE) of the observed versus modeled commuting flows by zone group. The Consultant will compile observed data for variables measuring the goodness-of-fit of the model from a variety of sources such as the regional household survey, on-board transit surveys (if available), 1990 CTPP data, CAMPO model results, traffic counts, and local transit ridership data. The Consultant will work with the City to define appropriate targets and criteria for model acceptance. The Consultant will prepare and deliver to the City in hard-copy, Microsoft Word, and Adobe.pdf formats, a working paper containing recommendations for model validation targets, a calibrated/validated peak period multi- modal travel model for San Marcos; and a technical memorandum documenting the assumptions, methodology, findings and products of this task. Transportation Masterplan K.wpd 6