CALINE4 (the California Line Source Model version 4) is used throughout the world to model near-road pollutant concentrations. STI's Paul Benson developed CALINE4 during his career with the California Department of Transportation. STI, together with researchers at UC Davis, developed a user-friendly version of CALINE4, called CL4, to support near-road pollutant modeling. STI’s most recent CL4 update makes it easier to complete near-road particulate matter and nitrogen dioxide assessments, in addition to the carbon monoxide analyses the model originally supported. STI software developers have programmed CL4 to:
  • Include onscreen programming tips that simplify near-road modeling
  • Improve compatibility with a wide range of desktop and laptop computing environments
  • Enable rapid assessment of multiple pollutant problems with an easy-to-use interface