VMT Mix Estimation Method Refinement for MOBILE6

Project Description

The on-road mobile source emissions estimation process requires vehicle classification data to develop locality-specific vehicle miles of travel (VMT) mix. Therefore, vehicle classification data are a critical part of the emissions estimation process. The Texas Transportation Institute (TTI) previously developed a method for converting vehicle classification count data collected in the Federal Highway Administration vehicle classification categories (based on axle spacing and/or vehicle length) into the eight Environmental Protection Agency categories. This methodology was subsequently modified and expanded to include the 28-vehicle classification types contained in MOBILE6. The MOBILE6 method now requires additional refinement based upon peer review of the current method and the availability of more detailed data. This task is for the review and assessment of the suggestions, recommendations, comments, criticisms, and proposed refinements relating to the current TTI VMT mix estimation practice. From these comments, combined with TTI's own experience with the MOBILE6 VMT mix category structure, a refined "best practice" was derived and documented.

For More Information