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• 1. [Article] Contextual Influences on Trip Generation

  There is national interest in building data that expands upon the existing Institute of Transportation Engineers (ITE) trip generation rates to include sites located in a multi-modal context. Current ITE ...

  Citation × Citation Citation Abstract Copy Title: Contextual Influences on Trip Generation Author: Clifton, Kelly J., Currans, Kristina Marie, Muhs, Christopher D. Year: 2012 There is national interest in building data that expands upon the existing Institute of Transportation Engineers (ITE) trip generation rates to include sites located in a multi-modal context. Current ITE rates represent travel behavior for development in single lots and uses, primarily measured in low-density suburban areas. Despite evidence that a more compact urban form, access to transit and a greater mix of uses generates fewer and shorter vehicle trips, local governments are often compelled to use current ITE trip generation rates to evaluate transportation impacts and calculate transportation system development charges (TSDCs). This is due to: a) the expense of collecting local data, b) lack of alternative sources of information, c) the strong industry bias toward using ITE published rates and d) the absence of a empirically tested methodology for adjusting those rates for development occurring in different land use and transportation contexts. Compounding these challenges, cities in Oregon are required to demonstrate that planning and zoning changes will not degrade the performance of state-owned transportation facilities compared to the levels of service documented in the Regional Transportation Plan under the Oregon Transportation Planning Rule, section -0060, and Oregon Highway Plan, Policy 1.F.6. These requirements can conflict with regional policies in Metro's 2040 Growth Concept that call for development of mixed-use centers and corridors to support jobs and freight reliability, a compact urban form and leverage transportation investments such as high capacity transit. Thus, there are gaps in the understanding about how best to evaluate, mitigate and plan for growth under these conditions. This research proposes to develop multi-modal trip generation rates that better reflect the relationship between land use, transportation and travel demand for specific land use types located in various urban settings. The project aims to collect local data (using multi-modal counts and establishment surveys) on a few specific land uses (deemed most problematic to estimate demand and occurring across the spectrum of urban conditions) to develop trip generation rates that are sensitive to demographic, land use and transportation contexts. These new trip rates will be compared to the ITE rates for the same land use category and a methodology for adjusting the ITE rates will be developed. This adjustment methodology will be validated, using additional data collected in this research. The research will be documented and made available to local partners and disseminated widely to reach out to other communities across the country. The research conducted for this project would account for how the built environment (e.g., both land use and transportation) influences travel behavior (number of trips, trip length, mode choice), and determine trip rates that reflect the entire activity spectrum of different development/place typologies. This is extremely important in determining the impact of different development types on the transportation system to: 1) avoid over-planning the system for the surrounding land uses; (2) suggest strategies and investment priorities to encourage more compact, mixed-use areas with more transportation choices and 3) avoid creating regulatory and/or financial barriers to compact form envisioned by local, regional and statewide plans (i.e. uniform TSDCs can result in lower impact development paying the same rates, and thus subsidizing development with higher impact costs to the transportation system). The documentation of the findings and methodology will be applicable to current and future growth and be transferable to other communities, locally and nationally, beyond the Portland region. Title: Contextual Influences on Trip Generation Author: Clifton, Kelly J., Currans, Kristina Marie, Muhs, Christopher D. Year: 2012 There is national interest in building data that expands upon the existing Institute of Transportation Engineers (ITE) trip generation rates to include sites located in a multi-modal context. Current ITE rates represent travel behavior for development in single lots and uses, primarily measured in low-density suburban areas. Despite evidence that a more compact urban form, access to transit and a greater mix of uses generates fewer and shorter vehicle trips, local governments are often compelled to use current ITE trip generation rates to evaluate transportation impacts and calculate transportation system development charges (TSDCs). This is due to: a) the expense of collecting local data, b) lack of alternative sources of information, c) the strong industry bias toward using ITE published rates and d) the absence of a empirically tested methodology for adjusting those rates for development occurring in different land use and transportation contexts. Compounding these challenges, cities in Oregon are required to demonstrate that planning and zoning changes will not degrade the performance of state-owned transportation facilities compared to the levels of service documented in the Regional Transportation Plan under the Oregon Transportation Planning Rule, section -0060, and Oregon Highway Plan, Policy 1.F.6. These requirements can conflict with regional policies in Metro's 2040 Growth Concept that call for development of mixed-use centers and corridors to support jobs and freight reliability, a compact urban form and leverage transportation investments such as high capacity transit. Thus, there are gaps in the understanding about how best to evaluate, mitigate and plan for growth under these conditions. This research proposes to develop multi-modal trip generation rates that better reflect the relationship between land use, transportation and travel demand for specific land use types located in various urban settings. The project aims to collect local data (using multi-modal counts and establishment surveys) on a few specific land uses (deemed most problematic to estimate demand and occurring across the spectrum of urban conditions) to develop trip generation rates that are sensitive to demographic, land use and transportation contexts. These new trip rates will be compared to the ITE rates for the same land use category and a methodology for adjusting the ITE rates will be developed. This adjustment methodology will be validated, using additional data collected in this research. The research will be documented and made available to local partners and disseminated widely to reach out to other communities across the country. The research conducted for this project would account for how the built environment (e.g., both land use and transportation) influences travel behavior (number of trips, trip length, mode choice), and determine trip rates that reflect the entire activity spectrum of different development/place typologies. This is extremely important in determining the impact of different development types on the transportation system to: 1) avoid over-planning the system for the surrounding land uses; (2) suggest strategies and investment priorities to encourage more compact, mixed-use areas with more transportation choices and 3) avoid creating regulatory and/or financial barriers to compact form envisioned by local, regional and statewide plans (i.e. uniform TSDCs can result in lower impact development paying the same rates, and thus subsidizing development with higher impact costs to the transportation system). The documentation of the findings and methodology will be applicable to current and future growth and be transferable to other communities, locally and nationally, beyond the Portland region. Close

• 2. [Article] Using Household Travel Surveys to Adjust ITE Trip Generation Rates

  The Institute of Transportation Engineers (ITE) Trip Generation Handbook has become the predominant method for estimating vehicle trips generated by development. The handbook is often criticized for its ...

  Citation × Citation Citation Abstract Copy Title: Using Household Travel Surveys to Adjust ITE Trip Generation Rates Author: Currans, Kristina Marie, Clifton, Kelly J. Year: 2015 The Institute of Transportation Engineers (ITE) Trip Generation Handbook has become the predominant method for estimating vehicle trips generated by development. The handbook is often criticized for its inability to account for multimodal behavior in urban contexts, often overestimating vehicle traffic. The purpose of this research is to develop and test a ready-to-use method for adjusting the ITE handbook vehicle trip generation estimates for urban context. This method was created using household travel surveys from Oregon, Washington, and Maryland, as well as nationally available built environment data. Three adjustments were estimated for eight general land-use categories, including a “pooled” category considering all travel survey data. The performance of three adjustments were tested using 195 establishment-level vehicle trip generation datasets compiled from three independent sources. Using this data, the performances of four land-use categories were tested. The overall findings suggest that the simplest of the three adjustments developed provided similar results to the more complex adjustment methods. Moreover, adjustments applied using the “pooled” land-uses category also provided similar results to the more detailed segmentation of travel survey data. Both of these findings punctuate the need for a simple, urban adjustment for trip generation estimates. Title: Using Household Travel Surveys to Adjust ITE Trip Generation Rates Author: Currans, Kristina Marie, Clifton, Kelly J. Year: 2015 The Institute of Transportation Engineers (ITE) Trip Generation Handbook has become the predominant method for estimating vehicle trips generated by development. The handbook is often criticized for its inability to account for multimodal behavior in urban contexts, often overestimating vehicle traffic. The purpose of this research is to develop and test a ready-to-use method for adjusting the ITE handbook vehicle trip generation estimates for urban context. This method was created using household travel surveys from Oregon, Washington, and Maryland, as well as nationally available built environment data. Three adjustments were estimated for eight general land-use categories, including a “pooled” category considering all travel survey data. The performance of three adjustments were tested using 195 establishment-level vehicle trip generation datasets compiled from three independent sources. Using this data, the performances of four land-use categories were tested. The overall findings suggest that the simplest of the three adjustments developed provided similar results to the more complex adjustment methods. Moreover, adjustments applied using the “pooled” land-uses category also provided similar results to the more detailed segmentation of travel survey data. Both of these findings punctuate the need for a simple, urban adjustment for trip generation estimates. Close