The complete guide to California smog check requirements

The state of California has a number of government organizations aimed at reducing harmful vehicle emissions, such as the Bureau of Automotive Repair (BAR) and the California Air Resources Board (CARB). In order to reduce emissions and combat climate change, these agencies have launched sweeping initiatives to meet ambitious climate goals and ensure California has access to clean air. 

For decades, the state of California has required smog testing for vehicle models older than eight years pursuant to the requirements set forth in BAR’s Smog Check Program. Similarly, to minimize unhealthy air pollutants emitted from commercial fleets, CARB passed a smog check regulation geared towards reducing emissions from heavy-duty vehicles known as the Clean Truck Check (CTC) regulation. Starting January 1, 2025, California’s emissions testing requirements are evolving. Under new CTC regulations, fleets operating in or entering California will need to conduct emissions tests twice annually, with testing intervals increasing to four times per year by 2027.

Ensuring compliance with these regulations is especially important for fleets that operate in California—agencies have acknowledged the role that technology can play in improving the efficiency of smog checks and keeping vehicles operating on the road. As a result, BAR recently launched the Continuous Testing Program (CTP) pilot, which allows government agencies to use telematics technology to achieve smog certification instead of having to undergo a manual in-person smog inspection. 

In addition, under the Clean Truck Check (CTC) regulation, medium and heavy-duty trucks and buses are permitted to leverage certified onboard diagnostics (OBD) systems to help meet the applicable periodic emissions testing requirements without the need of an in-person smog test. By leveraging innovative technology to streamline emissions testing, fleets are able to improve compliance, minimize downtime, and reduce operating costs.

With the right technology partner, commercial fleets can ensure they remain compliant with California’s emission standards. This comprehensive guide covers what you need to know about smog checks—including how heavy-duty fleets can leverage Samsara to streamline compliance management and improve efficiency.

What are smog checks? 

Smog checks are state-sponsored programs designed to identify cars that release excessive tailpipe emissions and pollutants. Instituted shortly after the Clean Air Act in 1966, these programs aim to reduce air pollution and vehicle emissions, and improve regional air quality to comply with local emissions regulations.

What happens if you don’t pass a smog check?  

In most cases, failing a smog check inspection means that you cannot complete your vehicle’s registration renewal, making it illegal to drive until you pass the smog check test. Once your vehicle passes, you are allowed to renew your registration and drive legally.

How much does a smog check cost? 

On average, a smog check can cost anywhere between $30-$60. Once your vehicle passes, the smog check administrator provides you with a state-issued sticker to display on your dashboard, proving that your vehicle has passed the smog check.

What are the smog check requirements for BAR and CARB inspections?

The California Department of Consumer Affairs’ Bureau of Automotive Repair (BAR) administers the California Smog Check Program. To improve the overall quality of smog checks, BAR created the California STAR Program, a certification program for test-only stations, repair stations, and test-and-repair smog check stations that wish to certify gross-polluting vehicles. According to the California Smog Check Program, with a few exceptions, vehicles more than eight model years old must be smog tested every two years. 

When it’s time for a smog check, vehicle owners may visit any of the 7,000 state-licensed and independently owned smog check stations throughout the state of California. If you’re looking for a location to complete your smog check, the California Bureau of Automotive Repair has a convenient auto shop locator for shops that are certified STAR stations. You can also complete a smog check at your nearest California DMV. According to BAR’s Continuous Testing Program (CTP) pilot, vehicles more than eight model years old must be smog tested every two years.

Under BAR’s Smog Check Program, smog checks were not required for diesel-powered vehicles with a gross vehicle weight rating of more than 14,000 pounds. However, the California Air Resources Board (CARB) recently passed the Heavy-Duty Inspection and Maintenance Program, known as Clean Truck Check, which requires non-gasoline powered heavy-duty vehicles (with a GVWR of more than 14,000 pounds) operating in the state of California to register with CARB and conduct periodic emissions testing to ensure that the vehicles’ emissions control systems are maintaining the same efficiency as the vehicle ages.

Under the Clean Truck Check regulations, vehicles that fail to meet the periodic testing requirements and emissions standards will be prohibited from operating in California until the emissions violations are corrected.

Who needs a smog check in the State of California? 

The BAR’s California Smog Check Program requires vehicles that were manufactured in 1976 or later to participate in the biennial smog check program in participating counties. Vehicles more than eight model years old—including government vehicles owned and operated by California cities and municipalities—must be smog tested every two years.

If you live in one of the following California counties, you need a smog inspection when you renew your Department of Motor Vehicles vehicle registration: Alameda, Butte, Colusa, Contra Costa, Fresno, Glenn, Kern, Kings, Los Angeles, Madera, Marin, Merced, Monterey, Napa, Nevada, Orange, Sacramento, San Benito, San Francisco, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Shasta, Solano, Stanislaus, Sutter, Tehama, Tulare, Ventura, Yolo, or Yuba. 

For CARB inspections under the Clean Truck Check program, heavy-duty trucks and buses with a GVWR greater than 14,000 pounds operating in California must conduct periodic testing and submit the data to CARB. Unlike light-duty smog checks, inspections for trucks and buses do not necessarily need to occur at a heavy-duty smog check station, and it is possible to leverage approved onboard diagnostics (OBD) solutions to collect the necessary data to complete these tests.

What to expect during your smog check inspection 

In order to receive a valid smog certificate, your vehicle must pass all parts of the smog check inspection. A smog check may include any of the following tests:

• Visual inspection of emission control components and systems.

• Functional inspection of the vehicle's check engine light, ignition timing, exhaust gas recirculation system, fuel evaporative system, and gas cap.

• Functional inspection of the vehicle's onboard diagnostic (OBD) system.

• Tailpipe emissions inspection, or emissions test.

LEARN MORE: The Importance of Fleet Maintenance Management 

What vehicles qualify for smog check exemptions? 

There are many exemptions to the California smog check program. These exemptions apply to newer vehicles, older vehicles, hybrid vehicles, electric vehicles, and more. If you’re wondering which vehicles qualify for an exemption, check the following list:

• Gasoline-powered vehicles manufactured in 1975 model year or older, including motorcycles and trailers.

• Diesel-powered vehicles manufactured in 1997 model year or older, or if it has a Gross Vehicle Weight Rating (GVWR) of more than 14,000 pounds.

• Vehicles powered by natural gas and weighing more than 14,000 pounds is not required to undergo a smog inspection.

• Fully electric vehicles are exempt from smog check requirements.

• Gasoline-powered vehicles less than eight model years old are exempt from biennial smog checks but must pay a smog abatement fee during registration renewal.

In addition, vehicles that are eight years old or less are exempt from a biennial smog check. If your vehicle qualifies, you can avoid a smog check by paying an annual $25 smog abatement fee or smog transfer fee.  

How to prepare for your smog check inspection

Taking your gasoline or diesel vehicles into a STAR station for a smog check can be time consuming and cause downtime. To ensure you’ll pass your smog check on the first try, here are some best practices to consider:

1. Clear your check engine light

Before you go in for your smog inspection, make sure your vehicle does not have its check engine light on. An illuminated check engine light is one of the few things that will cause an automatic failure of your smog check.

2. Drive your vehicle at highway speeds

It’s recommended that before you head in for your inspection, you drive your vehicle for at least 20 minutes. This will ensure that your vehicle is sufficiently warmed up so the dynamometer can properly measure your vehicle’s torque.  

3. Change the oil if it needed

If you’re approaching your next oil change milestone, it’s important to change the oil before your smog test. If the oil in your vehicle is too low or contaminated, it may cause an automatic failure. 

4. Make sure your vehicle is tuned up

If something in your vehicle is not running properly, the inspector is more likely to fail your vehicle’s smog inspection. Before you take your vehicle in for a smog check, make sure it’s been tuned up recently so that you save both time and money. 

5. Get a pre-inspection

Most smog check stations perform pre-inspections to provide you an opportunity to correct anything with your vehicle that could cause an automatic failure. 

6. Leverage Vehicle Telematics technology

With a Vehicle Telematics solution, it's possible to automate the smog checking process, improving operational efficiency. While smog checks can be time-consuming and disrupt productivity, a Vehicle Telematics system can enable you to automate smog checks and obtain the diagnostics data needed to streamline smog checks without an in-person inspection. This makes it possible for fleets to reduce downtime, minimize costs, and ensure compliance.

LEARN MORE: A Guide to Understanding DTC Codes 

Government fleets can bypass manual inspections with Samsara's BAR-CTP integration

Any fleet in California will need to meet the state’s Smog Check Program requirements, but government fleets in particular have unique requirements for environmental management. By passing smog check inspections, government agencies can reduce emissions and ensure city vehicles remain compliant. 

According to BAR’s Smog Check Program requirements, vehicles more than eight model years old must be smog tested every two years. For government agencies in California with thousands of city vehicles in their fleet, this can create a number of challenges, such as:

• Inefficiency: The hassle of in-person smog checks can create inefficiency, since drivers must go to designated smog check stations for smog inspections, deviating from scheduled routes and tasks. Completing paper-based vehicle inspection reports (VIR) can also be time-consuming and error-prone. 

• Vehicle downtime: With smog emissions tests taking 20 to 30 minutes per vehicle, in-person smog checks can cause fleet downtime. 

• Errors: Manual smog test reporting can be error-prone.

Recently, Samsara was approved to participate in the California BAR CTP program, providing public sector fleets the opportunity to bypass in-person inspections and streamline smog certification. With Samsara’s certified BAR CTP integration, BAR gains full visibility into vehicle diagnostic and engine data for all enrolled CTP vehicles—enabling them to grant compliant vehicles a passing score on their smog check, without the inefficiency of in-person manual inspections.

Samsara offers government agencies a number of significant benefits, including:

• Enhanced productivity: Alleviate the effort of in-person smog checks using telematics technology to automate reporting for key vehicle diagnostics data. 

• Reduced downtime: Eliminate the time needed for in-person smog inspections and keep your city vehicles on the road. 

• Improved efficiency and sustainability: Ensure that your city vehicles are running as cleanly and efficiently as possible by proactively monitoring maintenance needs.

Learn more about Samsara's California BAR CTP integration here.

Fleets operating in California can streamline emissions testing with Samsara’s CTC Manager

Under CARB’s CTC regulation, heavy-duty vehicles operating in or entering California will be required to conduct two emissions tests per year starting on January 1, 2025, with testing intervals increasing to four times per year by 2027. For fleets operating in California, compliance with the new CTC regulations can mean time consuming manual testing, non-compliance fees and penalties, and lost job opportunities due to non-compliance.

To stay ahead of California’s evolving emissions regulations, government fleets can now leverage Samsara’s CTC Manager, a comprehensive solution that includes remote emissions data capture and automated reporting.

With Samsara’s CTC Manager, fleets can:

• Minimize downtime and compliance costs, keeping vehicles on the road and fleets productive.

• Collect remote emissions data without the need for cumbersome in-person testing.

• Streamline compliance tasks with automated tracking and reporting.

By leveraging Samsara’s CTC Manager, public sector fleets are able to simplify compliance management by centralizing, automating, and reporting emissions tracking within Samsara’s unified platform. Fleet managers easily monitor which vehicles need testing and schedule checks directly in the Samsara Dashboard. This creates a streamlined experience, eliminating manual tracking and reducing administrative burden to allow teams to focus on other high-value priorities.

To learn more about how Samsara can help streamline emissions compliance and improve efficiency, reach out for a free trial or demo today.