Air quality estimation in project-level traffic forecasting

Some states and locales are in attainment of the national ambient air quality standards (NAAQS) from the Clean Air Act, so there is little need for air quality analysis for highway projects.

Otherwise, for guidance on estimating GHG emissions from HPMS data or from travel models, see FHWA’s, “Handbook for Estimating Transportation Greenhouse Gas Emissions for Integration into the Planning Process”. The methods presented in this Handbook are largely based on obtaining good VMT and speed estimates for a whole region. Emission factors may be improved by introducing a customized vehicle mix in MOVES. Although written for GHG gases, the advice in this Handbook applies equally well to the process of estimating energy consumption from highway vehicles.

Considerable advice on this subject may also be found in the report from NCHRP Project 25-25/Task 96, “Quick Reference Guide For Transportation Planners/Engineers: Generating Traffic & Activity Data for Project-Level Air Quality:Analyses”.

# References

FHWA, “Handbook for Estimating Transportation Greenhouse Gas Emissions for Integration into the Planning Process”

“Quick Reference Guide For Transportation Planners/Engineers: Generating Traffic & Activity Data for Project-Level Air Quality:Analyses” Prepared for AASHTO Committee on Environment and Sustainability. WSP USA, Inc. and Cambridge Systematics, Inc. July 2018. See http://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP25-25(96)_QRG.pdf