Incorporating the 10th Edition Institute of Traffic Engineers (ITE) Trip Generation Rates Into Virginia Department of Transportation Guidelines

About the report:

The Institute of Transportation Engineers (ITE) released the Trip Generation(TG) 10th edition in 2017, which significantly updated its database, and some of its trip generation rates were substantially lower than those of earlier editions. This study aims to investigate the applicability of the TG 10thedition in various Virginia contexts and to recommend how to incorporate the TG10th edition into state guidelines. The research team surveyed 31state transportation agencies to obtain a clear understanding of current practices in the adoption of trip rates and trip estimation approaches. We systematically compared trip rates of TG 9th and 10theditions using hypothesis tests and identified land uses with significant rate reduction. Trip generation data were collected from 37 sites in Virginia during weekday PM peaks for the mixed-use sites and single-use sites with significantly reduced 10th edition rates (multi-family low-rise and general office). To investigate the use of trip rates in different settings, general offices in both general urban/suburban and dense multi-use urban were considered. For mixed-use developments, we explored the combinations of four internal trip capture models and TG rates of 9th and 10theditions to identify the best trip estimation approach. Given that all trip data were collected after the outbreak of the COVID-19 pandemic, Streetlight data were used to adjust trip counts to account for the impacts of COVID. This study recommends that the VDOT Office of Land Use: 1) accept the TG 10thedition for the development of a Traffic Impact Analysis (TIA) should the 8thor 9th edition rates show a TIA is required and select 10thedition trip rates according to settings; and 2) accept the methodology presented in Trip Generation Handbook 3rd edition to estimate internal trip capture for mixed-use developments. This project will provide benefits to VDOT by improving the estimation of trip generation, which is critical in determining charges to developers for transportation improvements and making decisions concerning the modification of existing facilities and the design of new facilities

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