History of the California smog check program, 1984 to 2026

Are you trying to check your own smog check history

Many people who search for smog check history want a record for one car. You can look up any car's smog check history on the BAR inspection history page at bar.ca.gov/inspection. Results show up from midnight the day after the test. This works for your own car and for a used car you are thinking about buying. Our smog check history lookup guide walks through it step by step.

The rest of this guide is about the history of the program itself. It shows when smog checks started, how the rules changed and where the program stands in 2026.

When did smog checks start in California

Smog checks began in 1984. The Bureau of Automotive Repair, or BAR, launched the Smog Check program that year under SB 33, a law signed in 1982. BAR itself was created in 1972 in the Department of Consumer Affairs after the Automotive Repair Act of 1971. The program is a joint effort with the Department of Motor Vehicles and the California Air Resources Board.

The idea is simple. Find the cars that pollute the most and get them fixed. That basic deal has stayed the same for over 40 years. What changed is how the test is done and which cars are asked to take it.

1984 to 2009 the first generation

In 1994 AB 2018 followed the 1990 federal Clean Air Act amendments. It required loaded testing in the areas with the worst air, which BAR calls enhanced areas. In those areas a car sat on rollers, called a dynamometer, and was run under load so the test could measure nitrogen oxides. Basic and rural areas kept the simpler two speed idle test.

The state also built a support system. BAR formed an Educational Advisory Group in 1997 and a broader Advisory Group in 2001. In 2004 the Foundation for California Community Colleges took over the Smog Check Referee program, which handles special cases a regular station cannot. Those cars include kit cars, engine swaps and imports.

The new car exemption was one of the most felt rules for ordinary drivers. From 1998 until 2005 a new car skipped the renewal smog check for four model years. On January 1, 2005 it grew to six. The chart shows all three steps.

2010 the big rewrite

2010 was the biggest year for the program since 1994. AB 2289, a law by Assemblymember Eng, modernized almost everything.

• OBD focused testing. The law created a test that reads the car's own computer. BAR put it into use in March 2015 for model year 2000 and newer cars. Stations no longer put a probe in the tailpipe of those cars.
• STAR stations. The law created the STAR program, which began January 1, 2013. It replaced the older Gold Shield program, which ended December 31, 2012. STAR stations must meet higher performance standards and are the only stations that can certify directed and gross polluter vehicles.
• Stronger enforcement. The law gave BAR more tools against fraud and told it to evaluate the program and report to the public.

Diesel cars joined the program on January 1, 2010. Earlier, AB 1488 of 2007 had called for smog checks on diesel passenger cars and trucks newer than the 1997 model year and up to 14,000 pounds. That is why a 1998 diesel needs a smog check today. Read the diesel smog check guide for the details.

In 2008 the state raised the smog abatement fee by $8. In 2011 the Consumer Assistance Program repair help was limited to low income owners. Participation in repair help fell from about 50,000 cars a year in 2010 to under 2,000 in 2019.

2015 to 2019 hybrids, OBD and the eight year rule

Hybrids joined the program in January 2015. In March 2015 BAR started the OBD focused inspection for newer cars and ended the fill pipe restrictor test. In May 2015 rules on readiness monitors took effect. These monitors are self tests the car runs. The rules said how many could be incomplete at test time.

AB 1274 passed in 2017 and changed two things at once. The new car exemption grew from six to eight model years starting in 2019, and the smog abatement fee for years 7 and 8 became $25 instead of $20. Cars under eight years old now skip the renewal test, so the cars on the test floor skew older.

In July 2019 BAR added a check for permanent diagnostic trouble codes on 2010 and newer cars. A stored code can fail the car even if the light is off. That same year SB 210 ordered a heavy duty inspection program, which became Clean Truck Check.

2020 to 2026 tighter rules and a new truck program

In July 2021 BAR added a modified software check. Illegally changed engine software fails, and software with a CARB Executive Order passes. In July 2022 new STAR rules created a process to suspend a STAR station. In 2023 AB 1263 changed the Smog Check Performance Report to a report every two years, and Clean Truck Check began for heavy trucks. In July 2023 BAR also allowed 2007 and newer diesels to pass with both the particulate filter and NMHC catalyst monitors incomplete.

In 2024 BAR updated the rules for inspection equipment. The new rules set a better data acquisition device that can read new protocols, record where an inspection happens and spot OBD simulators used for fraud. Over 7,000 of those devices were in use.

On January 1, 2025 the CAP payouts increased. Repair help went to $1,450 and retirement payouts rose to $1,350 and $2,000. See the vehicle retirement guide. On October 1, 2025 a rule took effect that requires all readiness monitors to be complete. BAR says it will phase the rule in and announce changes well ahead of time, so the old allowances still apply in practice.

On July 1, 2026 stations had to follow the April 2025 Smog Check Manual and a new biometric device rule. Cars from model years 2026 and 2027 that use a new communication protocol, OBD on UDS, get a bypass on the OBD test for now, until updated devices are certified.

The eight year rule in plain terms

Today the rule is easy to apply. Add 8 to the model year of your gas, hybrid or alternative fuel car. That is the year of its first renewal smog check. A 2020 model needs its first renewal smog check in 2028. After that it follows the biennial cycle in the areas that require it. Diesel cars get no break, since there are no model year exceptions for diesel.

The table shows why a rule change matters so much. Under the old six year rule, a 2018 model would have been tested in 2024. The eight year rule moved that to 2026. Owners saved two years of checks on each new car. The smog abatement fee takes the place of the test. It is $20 a year for model years 1 to 6 and $25 a year for years 7 and 8.

The four year rule for sales is separate. A gas car that is four model years old or newer can be sold without a smog check. The buyer pays an $8 smog transfer fee to DMV instead.

The laws behind the history

Nearly every change in this timeline began as a bill. These are the ones that matter most.

The text of the main rules sits in Division 26 of the Health and Safety Code, starting at section 44000. Many details are in BAR regulations in Title 16 of the California Code of Regulations. When BAR changes a rule it publishes the draft on its regulatory actions page, so owners and shops can comment first.

What stayed the same for 40 years

• The state sets the standards and licenses the stations. BAR licenses stations and technicians, and it does not set what a shop charges.
• DMV enforces the result. A car that does not have a current certificate when it is due cannot renew its registration.
• Cars in cleaner air areas get less testing. The program still splits the state into enhanced, basic and change of ownership areas.
• Repair help exists for low income owners. CAP started as a broad repair program and is now aimed at income eligible owners.
• Older cars are tested harder. That is true in the data today. Cars from 1999 and older fail about one test in six.

What the data shows has changed

Fewer cars fail today than a few years ago. The first test fail rate fell from 10.1% in 2019 to 8.5% in 2025. The fleet is also getting newer, and newer cars fail less often. BAR does not name one cause. See California smog check by the numbers for the full tables.

The old car group is shrinking fast. Cars from model year 1999 and older were 16% of first tests in 2019 and 7% in 2025. These are the cars that still use the tailpipe test. They fail far more often than newer cars. Even so, BAR said in 2022 that cars from 1995 and older made up only about 7% of roughly 10 million inspections a year and about 20% of the excess emissions.

The station network has shrunk too. There were 8,831 licensed stations in 2019 and 7,329 in 2025. That is 17% fewer.

What is coming next

Several changes are on the calendar or under study.

• All readiness monitors complete. The rule is in force. BAR will phase in changes by vehicle as data show monitors can set.
• New device for new protocols. OBD on UDS cars need new data acquisition devices, which BAR calls DAD 2.0, before their OBD test is back on.
• A central network for old cars. BAR was granted authority to set up a contracted inspection network for 1995 and older cars. It is taking input on the design. BAR says this could cut clean piping, gassing and tanking, which are forms of fraud on the older cars.
• Clean Truck Check in October 2027. Trucks with OBD move to four tests a year. See the Clean Truck Check guide.
• CAP payouts. BAR can adjust them every three years starting July 1, 2028.
• The $8 smog fee ends on July 1, 2035.

If your car is due, find a station on the station finder.