• Taillights and brake lights are checked during the annual car inspection required by the state of Massachusetts.Close up detail of a classic car at a car show image by Rob Hill from Fotolia.com
  
  The state of Massachusetts requires that automobiles registered in the state be inspected once a year to ensure that they meet federal air pollution standards for emissions of greenhouse gases such as carbon dioxide and nitrogen oxide, as well as cancer-causing agents such as acetaldehyde and benzene. The annual inspection also includes a check of safety features such as windshield wipers and headlights. Massachusetts drivers take their automobiles to state-designated inspection stations where they pay a small fee to have the vehicle inspected. A car that passes inspection gets a dated sticker on the front windshield that affirms the car meets state standards.
  
  

Visual Overview

• The first thing the state-licensed inspector does is to inspect the car visually for problems such as leaking gasoline that could endanger the inspector or the public. If the inspector finds such a condition, it must be repaired before the inspection can go forward. At this time the inspector also asks to see the registration, checks the vehicle identification number and makes sure the license plate decal is up-to-date.
  
  

Emissions Test

• In the United States, transportation emissions are the greatest contributor to the problem of greenhouse gases, which cause global warming by trapping heat in the earth's atmosphere. Massachusetts conducts an emissions test to ensure that car engines are running as cleanly as they should be. Model year 1996 and newer passenger cars are given on-board diagnostic tests during which the technician connects the vehicle's on-board computer to an analyzer, which checks several systems including emissions. The test checks for diagnostic trouble codes, which indicate that a component of the emissions system, such as the catalytic converter or gas recirculation valves, is not working properly.
  
  

Safety Test

• During the safety test, which usually takes about 12 minutes, the inspector looks for or tests: the parking brake and service brake; the exhaust system's muffler and the color of the smoke coming out of the tailpipe; steering and suspension (steering wheel, suspension, springs, shocks); horn; windows and windshield wipers; rearview and other mirrors; headlights, taillights, brake lights and reflectors; tires and wheels; the car's frame, bumpers, fenders, floor pans and fuel tank; vehicle height; seat belts; air bags and fuel tank cap.
  
  

If the Cars Fails

• A car that does not pass inspection in Massachusetts gets a rejection sticker. The owner has 60 days to repair the car and have it retested in order to get an up-to-date inspection sticker. Under some circumstances, an owner can be granted a waiver for the emissions part of the test. Waivers are not granted for safety violations. If the car fails inspection and the owner believes it should have passed, he may ask that the Registry of Motor Vehicles investigate and have the car put through another, "challenge," inspection.