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What is a Test Only?

Test-Only Directed Vehicles

In order to comply with state law, the California Department of Consumer Affairs/Bureau of Automotive Repair (DCA/BAR) directs a portion of the vehicles registered in Enhanced Smog Check Areas to Test-Only stations. Enhanced Areas are those parts of the state with "serious," "severe," or "extreme" ozone pollution problems.

What is a Test-Only? Test-Only facilities are licensed Smog Check stations that, by law, are only allowed to test cars; they cannot repair them. Any needed repairs must be performed elsewhere at either a Smog Check station designated as a Test-Repair or Gold Shield station. To learn more about the various station types, and what station best fits your Smog Check needs, click here.

High Emitter Profile - The majority of vehicles directed to Test-Only stations are selected by application of the High Emitter Profile (HEP), which identifies the vehicles most likely to fail their Smog Checks. The High Emitter Profile (HEP) uses data from several different sources. Some of it comes from the state Vehicle Identification Database (VID), which collects data from each Smog Check performed in California. The VID is used by the Department of Motor Vehicles (DMV), BAR, and other government agencies. In addition, general vehicle data such as make, model-year, vehicle miles traveled, and engine size help define the HEP.

This information is used to determine which vehicles are most likely to fail their Smog Checks, especially at Gross Polluter levels--at least two times the emissions level allowed for a particular vehicle. No single factor identifies a vehicle for a Smog Check to be done at a Test-Only station. The data is weighted and vehicles selected using this computer profiling of vehicles most likely to fail their Smog Check. DCA/BAR has gradually increased the number of vehicles directed to Test-Only stations to meet the air quality improvement goals of the State Implementation Plan (SIP). The SIP is a blueprint outlining the methods California will use to meet federal air quality standards.

Two Percent Randomly Selected - As required by State law, two percent of the vehicles in the Enhanced Areas are also directed to Test-Only stations for their Smog Checks. These vehicles are selected randomly to evaluate the overall effectiveness of the Smog Check Program.

How Motorists are Notified - The Department of Motor Vehicles (DMV) notifies owners of vehicles that have been selected to have their Smog Checks performed at Test-Only stations. The registration Renewal Notice sent for these vehicles will say "Smog Certification Required at Test-Only Center".

Consumer Assistance Program - You may qualify for up to $500 in financial assistance to repair your car if it requires a Smog Check at a Test-Only station and failed that test. Click here for more information on the Consumer Assistance Program or visit our Web site at


This Information is from the 

  Bureau of Auto.  Repair
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