Roads and Links

• It is very important to have accurate emission estimates from the mobile
  sources, one of the major NOX emitters in the Houston-Galveston
  area (HGA);
• HGAC-developed link-based VMT (Vehicle Mileage Traveled) data for
  the area is used as input to EPA's MOBILE6.2;
• Compared to county-based emissions inventory, the link-based MOBILE
  6.2 emissions can increase accuracy by applying VMT data to generate hourly emissions;
• Along with ozone precursors species, air toxic emissions are estimated with
  the link-based VMT data for CMAQ-TOXIC simulations.