California is leading the charge in reducing vehicle emissions through forward-thinking legislation and programs overseen by agencies like the Bureau of Automotive Repair (BAR) and the California Air Resources Board (CARB). These agencies are responsible for implementing bold initiatives to meet the state’s climate goals and ensure clean air for all Californians.
New Requirements for Smog Check Coming in 2025:-
For years, California has required biennial smog checks for vehicles more than eight model years old under BAR’s Smog Check Program . Now, CARB is expanding its efforts to include heavy-duty vehicles. The Clean Truck Check (CTC) regulation, effective January 1, 2025, mandates that commercial fleets operating in or entering the state conduct emissions tests twice per year—ramping up to four times annually by 2027.
These evolving standards are designed to reduce pollution from diesel and other non-gasoline heavy-duty vehicles and ensure that emissions control systems remain effective over time.
Technology is Driving a Smarter Way to Comply:-
Recognizing the challenges that traditional in-person inspections pose for large fleets, BAR launched the Continuous Testing Program (CTP) pilot. This initiative allows telematics-based emissions data to be used in place of physical inspections, saving fleets valuable time and reducing vehicle downtime.
CARB also allows certified onboard diagnostic (OBD) systems to meet periodic testing requirements for medium- and heavy-duty vehicles under the CTC program—another way to bypass manual inspections.
What Are Smog Checks?
Smog testing are mandated emissions tests that help identify vehicles emitting excessive pollutants. Established after the Clean Air Act of 1966, these tests ensure compliance with state and federal air quality standards. Vehicles that fail cannot be legally registered or driven until repairs are made and the vehicle passes retesting.
How much does smog check cost?
A typical smog check cost in California is between $30 and $60. Most gasoline-powered vehicles more than eight model years old must undergo testing every two years. Exemptions apply to:
• 1975 or older gasoline vehicles
• 1997 or older diesel vehicles, or those over 14,000 lbs GVWR
• Natural gas vehicles over 14,000 lbs
• Electric vehicles
• Newer gasoline vehicles (less than 8 years old), which instead pay a smog abatement fee
What are the smog check requirements for BAR and CARB inspections?
The California Bureau of Automotive Repair (BAR) oversees the state’s Smog Check Program, which is designed to identify and reduce vehicle emissions. To ensure consistent quality, BAR established the STAR Program—a certification system for test-only, repair-only, and test-and-repair stations that are authorized to inspect high-emitting vehicles. In general, most vehicles that are more than eight model years old are required to undergo a smog check every two years, with some exceptions.
Vehicle owners can choose from over 7,000 licensed smog check stations across California, many of which are STAR-certified. BAR also offers an online auto shop locator to help drivers find nearby certified stations. Alternatively, smog checks may be completed at select California DMV locations. Under BAR’s Continuous Testing Program (CTP) pilot, certain vehicles may even qualify for remote smog certification using telematics data, replacing the need for an in-person inspection—though the same biennial testing requirement applies.
Historically, diesel vehicles over 14,000 pounds in gross vehicle weight rating (GVWR) were exempt from BAR’s standard smog checks. However, the California Air Resources Board (CARB) has since introduced the Clean Truck Check —a Heavy-Duty Inspection and Maintenance Program requiring non-gasoline powered heavy-duty vehicles (GVWR over 14,000 pounds) operating in California to register with CARB and undergo regular emissions testing. This ensures that emission control systems continue to function properly as vehicles age.
Vehicles that fail to meet CARB’s emissions standards or testing requirements will not be permitted to operate within California until all compliance issues are resolved.
Who Needs a Smog Check?
If your vehicle was manufactured in 1976 or later and is registered in a participating California county, it will likely require biennial smog testing. Participating counties include major regions like Los Angeles, Orange, Alameda, and Sacramento. See the full list here.
For fleets under CARB’s Clean Truck Check, any diesel-powered truck or bus with a GVWR over 14,000 pounds operating in California must be registered with CARB and pass periodic emissions testing.
What to Expect During an Inspection:-
A smog check may include:
• Visual inspection of emissions components
• Functional tests of systems like the fuel evaporative and exhaust gas recirculation systems
• A check engine light test
• Tailpipe emissions measurement
• OBD diagnostics scan
Which Vehicles Are Exempt from Smog Check Requirements?
Not all vehicles in California are subject to regular smog checks. The state offers several exemptions based on a vehicle's age, fuel type, and weight class. If you're unsure whether your vehicle qualifies for an exemption, here’s a breakdown of the most common categories:
Gasoline Vehicles (1975 or Older):-
Gasoline-powered cars, motorcycles, and trailers manufactured in 1975 or earlier are exempt from smog check requirements.
Diesel Vehicles (1997 or Older or Over 14,000 lbs GVWR):-
Diesel-powered vehicles are exempt if they meet either of the following criteria:
• Manufactured in 1997 or earlier, or
• Have a Gross Vehicle Weight Rating (GVWR) over 14,000 pounds
Natural Gas Vehicles Over 14,000 lbs:-
Vehicles powered by natural gas and weighing more than 14,000 pounds are not required to undergo smog inspections.
Fully Electric Vehicles:-
All fully electric vehicles (EVs) are automatically exempt from smog check requirements.
Newer Gasoline Vehicles (Under 8 Model Years Old):-
Gasoline-powered vehicles that are less than eight model years old are exempt from the biennial smog check requirement. However, owners must pay a smog abatement fee, typically $25 per year, when renewing registration.
In summary, if your vehicle falls into any of these categories, you may not need a smog check—but be sure to stay current with any applicable fees or documentation. Always verify your exemption status through the California DMV or BAR (Bureau of Automotive Repair) to ensure compliance.
How to Prepare for Your Smog Check Inspection:-
Taking your gasoline or diesel vehicle to a STAR-certified smog check station can be time-consuming and may lead to unexpected downtime—especially for fleet operators. To help ensure your vehicle passes on the first attempt, here are several best practices to follow:
1. Check for an Illuminated Engine Light
One of the most common reasons vehicles fail a smog check is an active check engine light. Before your inspection, ensure there are no warning lights illuminated on your dashboard. Even if your vehicle is running smoothly, an active light will typically result in automatic failure.
2. Warm Up Your Vehicle Before the Test
Before heading to the testing station, drive your vehicle at highway speeds for at least 20 minutes. This warms up the engine and ensures that the emissions control system is operating at optimal efficiency—especially important for accurate readings on the dynamometer used during the test.
3. Change the Oil if Needed
If your vehicle is nearing its oil change interval, have the oil replaced before the smog test. Dirty or low oil can interfere with emissions testing by affecting the performance of your engine, potentially resulting in a failed inspection.
4. Ensure the Vehicle Is Properly Tuned
A well-maintained vehicle is far more likely to pass a smog test. If your engine is running rough, misfiring, or experiencing issues with fuel or air intake, these problems can increase emissions. Make sure your vehicle has been recently serviced or tuned to catch and fix any issues beforehand.
5. Request a Pre-Inspection
Many smog check stations offer pre-inspections that identify any potential issues before your official test. This gives you the chance to make necessary repairs without the risk of an immediate fail being reported to the DMV.
6. Use Vehicle Telematics for Smog Compliance
For fleets or high-usage vehicles, Vehicle Telematics solutions can dramatically streamline the smog check process. By collecting real-time diagnostic data, telematics systems can help:
• Monitor engine health and emissions system performance
• Detect issues before they lead to a failed inspection
• Submit remote smog certifications under programs like BAR’s Continuous Testing Program (CTP)
Telematics tools not only reduce downtime and manual inspection costs, but also help ensure ongoing compliance with California’s emissions regulations.
Streamlining Compliance for Government Fleets:-
Government fleets face added complexity due to the volume of vehicles and the inefficiencies of manual smog checks. These challenges include:
• Operational inefficiency: Drivers must deviate from routes to complete inspections
• Vehicle downtime: In-person smog checks take 20–30 minutes per vehicle
• Reporting errors: Manual data entry increases the risk of compliance issues
To address these issues, ELD Mandate now integrates with the California BAR CTP program. This enables public fleets to automate smog compliance using telematics data, eliminating the need for in-person inspections and significantly reducing downtime.
Key Benefits for Government Agencies Using ELD Mandate’s BAR CTP Integration:
• Increased productivity: No more trips to smog stations
• Reduced downtime: Vehicles stay on the road
• Improved sustainability: Monitor and maintain optimal vehicle performance
Meet CARB’s Clean Truck Check Standards with ELD Mandate CTC Manager:-
Starting in 2025, commercial fleets will need to submit emissions data twice annually under CARB’s Clean Truck Check, increasing to quarterly by 2027. ELD mandate’s CTC Manager helps fleets stay compliant by:
• Automating emissions data collection and reporting
• Centralizing compliance tracking in one dashboard
• Minimizing vehicle downtime
Fleet managers can see which vehicles need testing and schedule them proactively, all within ELD Mandate’s platform—saving time, reducing penalties, and ensuring compliance.