You probably just got a notice from the Department of Motor Vehicles that requires you to get a smog check or emissions test before you are able to get a new sticker for your car. For your information, depending on the state where you live, vehicles which are powered by gasoline which are produced after 1975 need to meet certain emissions standards.
The Federal Clean Air Act was amended in 1990 with the aim to reduce the unhealthy pollutants in the air. That’s why EPA or the Environmental Protection Agency made standards to help reduce harmful pollutants which are emitted into the air by vehicles.
However, not all states in the U.S. require a smog check. Some states that require a smog check are California, Colorado, Delaware, Louisiana, Vermont, and District of Columbia. In some other states, smog check is not required or it is only required for certain cities or counties or certain vehicles.
How Long Does It Take?
Now, the question is, how long does it take to perform a star smog check? As explained on the Bureau of Automotive Repair site, it may take more time to perform accurate Smog Check inspections. However, generally it can take around 20 to 30 minutes. It is for a comprehensive inspection including determining proper inspection procedures accurately and performing the visual inspection and all applicable functional tests. However, if the inspector has many experiences and is familiar with the vehicle, it can take less than that. Nevertheless, there is evidence shown by the results on the STAR short-term performance measures where it shows that there are a lot of inspectors who are making more mistakes than they realize. So, it is better to slow down and do it correctly.
The Testing Methods of Smog Test
The testing methods of smog test depends on the state where you live and also the type and model of vehicle that you have. However, here are the most common testing procedures.
1. OBD or On-Board Diagnostic Inspection
Cars that were manufactured from 1996 and up usually use this method. The thing that will be performed by the smog inspector is to plug their state-certified device into your on-board computer diagnostics system and monitor the emissions levels from your exhaust. Let’s say that it goes well after the smog check is done. If so, you will be on your way, but if there is something wrong, there will be a fault code and you have to diagnose and repair the issue.
2. ASM or Acceleration Simulation Mode test
Since many cars that were manufactured before 1996 do not have an OBD system, a dynamometer will be used by the technician where it works as a driving simulator while a sensor is put in the exhaust pipe so that it detects the levels of pollutant.
3. TTI or Two-Tier Idle test
For cars which are manufactured between 1976 and 1995, this test is usually performed because these cars have variable idling and timing. In this test, exhaust missions will be tested at both higher and lower speeds.
Vehicles That Are Chosen for a Star Smog Check
Some vehicles can be tested at a regular smog check station, but some others need to be tested at a Star station. So, what vehicles are required to go to a Star station? There are three criteria which are used by the State of California to determine which vehicles that can go to a Star station.
1. Gross Polluters
If a vehicle has failed in a previous smog inspection and the emissions are high, then you will be required to go to a Star station.
2. High Emitter Profile
The other vehicles that will have to go to a Star station for smog check are certain types of vehicles that have been identified by the BAR as having a high chance of failing the smog inspection.
3. Random Sampling
A random sample of all vehicles that are registered in California which are driven on public roads is chosen by the BAR to get a smog check at a Star station.
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