[PDF] A Methodology For Generating Disaggregate Truck Data For Texas Statewide Analysis Model eBook

Author : Akshay Mani
Publisher :
Page : 260 pages
File Size : 35,92 MB
Release : 2004
Category : Information storage and retrieval systems
ISBN :

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The following research describes a novel approach for generating disaggregate county-level truck data for Texas from publicly available freight data sources. County-level truck flows are required as inputs to the Statewide Analysis Model (SAM), a multi-modal freight planning model developed by the Texas Department of Transportation, to analyze the freight system performance and make critical infrastructure improvement decisions. TxDOT currently relies on the commercial Reebie Associates' TRANSEARCH database for inputs to the SAM, since it is the only available freight data source providing comprehensive county-level truck flow data for Texas. However, the sources, methodology, and assumptions used in compiling the database are proprietary, which have raised questions regarding the reliability of the data. Since statewide primary freight data collection is an expensive and time-consuming process, there is a need for methods to extract disaggregated data from secondary freight data sources. The current research addresses this need by developing a model to generate county-level truck flows for Texas from the publicly available Commodity Flow Survey. The methodology is applied to compute inter-county, county-to-state and state-to-county truck flows for Texas for nine major commodity categories. Though the generated truck data suffer from certain limitations associated with the CFS, the approach provides a cost-effective means of estimating county-level truck flows in Texas, of which the limitations, assumptions and measures of reliability are well documented

Author :
Publisher :
Page : 343 pages
File Size : 47,33 MB
Release : 2006
Category : Freight and freightage
ISBN :

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The Texas Department of Transportation (TxDOT) developed the Texas Statewide Analysis Model (SAM) to provide analysis and forecasting capabilities of passenger and commodity/freight movements in Texas. The SAM provides data and results at a level that is more aggregate than that typically accomplished within urban areas in their travel demand models. Travel demand models for urban areas typically concentrate on person estimates and at an aggregate level also estimate commercial vehicle (i.e., truck) movements. To produce consistent compatible estimates of passenger and commodity/freight movements, agencies have not integrated the SAM and urban travel demand models. The purpose of this research was to provide a Texas analysis model that would disaggregate statewide estimates of commodities/freight within the Texas traditional urban travel demand model boundaries. The research has developed a disaggregation model for integrating the SAM commodity estimates into the urban framework and a "bottom-up" model for estimating the commodity movements internal to the urban area that occur in addition to statewide movements. The integration of the SAM estimates involves disaggregation of internal to internal, external to internal, and external to external movements. The SAM accomplishes disaggregation using existing demographic data at the urban level. The urban model component uses data from typical urban travel demand models, including software currently used by TxDOT in their urban travel demand models. Modeling data such as shipping/receiving rates, trip length, load factors, etc. were developed from travel surveys done as part of the state travel survey program. The urban model also specifically estimates vehicle (truck) movements that do not involve the transfer of commodities as well as movements of empty vehicles. Included in the research was the application of the urban model and integration of the SAM estimates for the Houston-Galveston Area to develop estimates of commodity movements in the Houston-Galveston Area and estimate the truck movements associated with those commodities.

Author : Stasa Vojin Zivojnovic
Publisher :
Page : 368 pages
File Size : 13,43 MB
Release : 2015
Category :
ISBN :

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Transportation projects do not necessarily get evaluated for economic value or impact even though arguably most projects are done to advance the economy in the long run, from inducing travel to improving market access. Those studies that do provide an economic study in their reports do not explain the methodology or critique the economic study process. This thesis takes a look at using the Texas Statewide Analysis (SAM) in combination with the Transportation Economic Development Impact System (TREDIS) to better understand the bearing a transportation project, or group of projects, may have on a region. The overview and critique of the SAM-TREDIS methodology is completed using a few scenarios of groups of projects for the Texas study region, for which one scenario includes the implementation of HSR in the Texas Triangle. The scenario of high-speed rail is explored as to encourage a future discussion to create a more concrete plan regarding future HSR. While the outputs of SAM for most Texas transportation scenarios were too subtle in difference between scenarios to create informative TREDIS outputs, they provided an in-depth look in the use of SAM and TREDIS separately and collectively. Overall, this method is useful at looking at future roadways projects that produce a moderately significant change in travel characteristics. Another model, or an improved SAM, is recommended for an accurate HSR study.

Author : Michael J. Fischer
Publisher :
Page : 92 pages
File Size : 20,32 MB
Release : 2001
Category : Business & Economics
ISBN :

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TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 298: Truck Trip Generation Data identifies available data and assesses the current state of the practice in truck trip generation.

Author : Alan J. Horowitz
Publisher : Transportation Research Board
Page : 125 pages
File Size : 11,65 MB
Release : 2006
Category : Traffic estimation
ISBN : 0309097657

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TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 358: Statewide Travel Forecasting Models examines statewide travel forecasting models designed to address planning needs and provide forecasts for statewide transportation, including passenger vehicle and freight movements. The report explores the types and purposes of models being used, integration of state and urban models, data requirements, computer needs, resources (including time, funding, training, and staff), limitations, and overall benefits. The report includes five case studies, two that focus on passenger components, two on freight components, and one on both passenger and freight.