Testing Hours / Schedule
Failures & Retests
Massachusetts requires emissions testing on vehicles and they have set up Motorist Assistance Centers (MACs) in order to help you be able to identify any issues or problems with your vehicle in the event that it fails its initial emissions inspection.
The emissions testing process is done by having an emissions technician run a test of your vehicle’s on-board diagnostics (OBD). This is a computer system that tracks your car’s performance and logs any issues that the car has concerning emissions.
If your vehicle is from 1998 or newer it will be tested using the OBD test process. If your vehicle is a light duty diesel based vehicle and it weighs less than 8,500 lbs it will also be required to have a OBD test. And the same with medium duty diesel vehicles from 2007 or newer which weigh between 8,500-14,000 lbs and medium duty non-diesel vehicles which weigh the same and are from 2008 or newer. The years mentioned relate to the year that your vehicle was manufactured in.
There is a test called the Opacity Test for medium and heavy duty diesel vehicles which way more than 10,000 lbs but do not have an on-board diagnostic system. Vehicles that were manufactured prior to 1998 no longer are required to receive a tailpipe emissions test, though they will fail a safety inspection if there is smoke coming from their tailpipes that is visible to the eye.