Carbon monoxide screen for signalized intersections COSIM, version 3.0 : technical documentation.

0197-9191PDFTech ReportFHWA-ICT-08-019FHWA-ICT-08-019, UILU-ENG-2008-2006R27-7Air qualityExhaust gasesAir quality managementCarbon monoxideMultivariate analysisIllinoisIllinois Center for TransportationPeters, ScottIllinois Center for TransportationIllinois. Dept. of Transportation. Bureau of Materials and Physical ResearchNTL-ENERGY AND ENVIRONMENT-Air QualityNTL-REFERENCES AND DIRECTORIES-StatisticsUS Transportation CollectionThe Illinois Department of Transportation (IDOT) currently uses the computer screening model IllinoisCO Screen for Intersection Modeling (COSIM) to estimate worst-case CO concentrations for proposed roadwayprojects affecting signalized intersections. The original model was developed as part of the IllinoisTransportation Research Center (ITRC) research project IIIA-H1, FY 97, completed in October 1999. Modeledresults from Version 1.0 and 1.1 of COSIM are based on the U.S. Environmental Protection Agency\ue2\u20ac\u2122s (USEPA)mobile source emission model, MOBILE5b, and roadway dispersion model, CAL3QHC v 2.0 (Larson, 1999).The second version of COSIM was released in 2003. Version 2.0 incorporated new emission factor (EF) tablesdeveloped using USEPA\ue2\u20ac\u2122s updated version of the MOBILE model called MOBILE6. In addition to updating theemission factors used in COSIM, pre-screen criteria for determining when COSIM needs to be used for aroadway project were developed and incorporated into COSIM as a Pre-Screen feature (Larson, 2003). In2007, regulatory changes in the Illinois vehicle Inspection and Maintenance (I&M) program prompted the IllinoisEnvironmental Protection Agency (IEPA) to recommend that IDOT update COSIM with new EF tables using theMOBILE6.2 model. Based on this recommendation, IDOT and the Illinois Center for Transportation (ICT)provided funding to update the COSIM model. As part of the update, IDOT also requested that the methodologyused in creating the original Pre-Screen criteria be reevaluated and possibly revised based on the findings of theevaluation. This report provides technical documentation on the updates and revisions made to Version 3.0 ofCOSIM finalized in June 2008