Welcome to the Connecticut Emissions Program

The Modified Snap Acceleration (MSA) test is for older diesel-powered vehicles. The emissions analyzer will utilize an opacity meter to measure the density of smoke emitted from the vehicle’s tailpipe.

Vehicles subject to the Modified Snap Acceleration (MSA) include:

  • 2006 and older diesel-powered vehicles with the GVWR between 8,501 LBS to 10,000 LBS.
  • All 1996 diesel-powered vehicles with the GVWR up to 10,000 LBS.

Please note that NOT all Test Centers can accommodate this emissions test. Please contact the motorist hotline at 1-888-828-8399 or click here to find the closest Full-Service Test Center.

In addition to this test, all vehicles are subject to the visual verification of the catalytic converter; if one or more catalytic converters are missing from your vehicle, the emissions test will fail.