2023 Carbon Monoxide Categorical Hot-Spot Finding Technical Report

This technical report describes the modeling analysis conducted to support the 2023 Federal Highway Administration (FHWA) carbon monoxide (CO) categorical hot-spot finding for intersections using Motor Vehicle Emission Simulator (MOVES3) and CAL3QHC. The finding does not apply to California, which uses EMFAC for its emissions model. The 2023 CO categorical finding replaces the single intersection of perpendicular highways modeled in the 2017 CO categorical finding with a skewed intersection modeled with four different scenarios of grade and truck percentages. These changes allow for wider application of the finding. Each scenario can be applied in a rural or urban area. This revised finding also modifies the acceptable ranges of modeling parameters based on FHWA’s latest understanding of worst-case conditions. A comparison of the acceptable ranges of modeling parameters between the 2017 finding and the 2023 finding is found in Appendix A. Information on how to apply the finding as part of a project-level conformity determination is found in FHWA’s CO categorical hot-spot finding, which is available on FHWA’s CO categorical hot-spot finding website. Modeling files for MOVES3 and CAL3QHC are available via request from FHWA’s Air Quality and Transportation Conformity Team at TAQC@dot.gov.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 33p

Subject/Index Terms

Filing Info

  • Accession Number: 01873371
  • Record Type: Publication
  • Created Date: Feb 22 2023 9:38AM