Which Vehicles Are Required to Comply With CARB Clean Truck Check?

Key Takeaways

• Clean Truck Check applies to nearly all diesel, alternative fuel, and hybrid heavy-duty vehicles with a manufacturer’s gross vehicle weight rating over 14,000 pounds that operate on California public roads and highways, including vehicles not registered in California.
• The program reaches far beyond long-haul trucking. Concrete mixer trucks, dump trucks, refuse trucks, tow trucks, heavy service vehicles, local delivery trucks, and large box trucks are all potentially covered if they meet the weight and fuel-type criteria.
• Out-of-state fleets based in Arizona, Texas, Nevada, New Mexico, Utah, Oregon, and other states are subject to the same compliance obligations as California-registered trucks when their vehicles operate in California.
• CARB confirmed on March 10, 2026, that Clean Truck Check enforcement remains fully in effect for out-of-state vehicles, covering reporting, annual compliance fees, and emissions testing.
• OBD-equipped vehicles (2013 and newer diesel engines and 2018 and newer alternative fuel engines) are tested with a CARB-certified OBD device. Older diesel engines require a smoke opacity test plus a visual inspection.
• Most covered vehicles currently need two passing emissions tests per year. Starting October 1, 2027, OBD-equipped vehicles are scheduled for four tests per year; qualifying agricultural vehicles and California-registered non-commercial motorhomes remain annual.
• CARB enforces the program using emissions screening devices, automated license plate readers, roadside inspections at border crossings, ports and railyards, and coordination with the California Highway Patrol.

Introduction

If a covered heavy-duty vehicle operates on California public roads or highways, Clean Truck Check can apply even when the vehicle and fleet are based elsewhere. The first checks are its manufacturer GVWR, fuel or powertrain, and whether a specific exclusion applies.

The California Air Resources Board’s Clean Truck Check program, formally known as the Heavy-Duty Inspection and Maintenance program, exists to verify that emissions control systems on heavy-duty vehicles are working correctly. Its scope is intentionally broad. CARB designed it to cover not just long-haul semi trucks but the full range of heavy vocational equipment that moves freight, hauls materials, and delivers goods across California’s roads every day. Concrete mixer trucks, dump trucks, tow trucks, refuse vehicles, local delivery trucks, and large box trucks all fall inside the program if they meet the weight and fuel-type criteria.

The out-of-state reach of this program is the part that catches most fleet owners off guard. An Arizona operator running loads into Los Angeles, a Texas carrier making seasonal runs through the Central Valley, and a Nevada company whose vehicles transit through California on interstate routes all face the same obligations under Clean Truck Check that a California-based carrier does. CARB reiterated this directly on March 10, 2026, confirming that out-of-state enforcement remains fully in effect and that roadside inspection activity at border crossings, ports, and railyards is ongoing.

This guide explains which vehicles are covered, the main exclusions, testing type and frequency, and key owner obligations. Clean Truck Check is an emissions program, separate from the federal ELD rule. For a broader overview, see our Clean Truck Check guide. To discuss a fleet setup, call (800) 261-4361 or contact our team.

Which Vehicles Must Comply With CARB Clean Truck Check?

Clean Truck Check applies to nearly all diesel, alternative fuel, and hybrid heavy-duty vehicles with a manufacturer’s gross vehicle weight rating (GVWR) over 14,000 pounds that operate on California public roads and highways, even if they are not registered in California.

Coverage starts with three questions: is the manufacturer GVWR greater than 14,000 pounds, does the vehicle use diesel or an alternative non-gasoline fuel (including a hybrid with such an engine), and does it operate on California public roads or highways? The vehicle’s business purpose, home state, and CDL status do not by themselves decide Clean Truck Check applicability. Check the specific exclusions below.

CARB specifically includes motorcoaches; transit, shuttle, and school buses; hybrid vehicles; commercial vehicles of all types; personal vehicles that meet the weight threshold; California-registered motorhomes; single-vehicle fleets; and vehicles registered in other states. That last category is critical for any fleet operating across state lines.

Does the Vehicle’s Commercial Purpose Change Whether It Is Covered?

No. Commercial use is not required. A qualifying privately owned vehicle or California-registered motorhome can be covered, while an otherwise similar gasoline-only or zero-emission vehicle is not. Apply the GVWR, fuel, California-road use, and exclusion tests to the particular vehicle.

What About Vocational Trucks That Rarely Leave One County?

Local operation does not create an exemption. A refuse truck operating within one California city, a concrete mixer that never travels more than twenty miles from its dispatch yard, and a dump truck on a local construction site in San Bernardino are all covered if they meet the weight and fuel-type criteria and operate on California public roads. The program has no local-area carve-out.

Which Specific Vehicle Types Fall Under the Program?

Clean Truck Check reaches well beyond the long-haul trucking fleets most people picture when they think about heavy-duty compliance.

Construction and Earthmoving Vehicles

Concrete and cement mixer trucks are among the clearest examples of covered vocational vehicles. These trucks typically run on diesel, carry GVWR ratings well above 14,000 lbs, and use California public roads daily on routes between batch plants and job sites. Dump trucks used in construction, quarrying, and site preparation fall under the same rules.

Heavy construction support vehicles, including water trucks, fuel tankers, and large flatbed haulers that use public roads between sites, are also typically covered. If a vehicle operates exclusively on a private job site and never uses a public road, verify its status with your compliance team, since the program specifically covers vehicles on public roads and highways.

Local Delivery and Service Vehicles

Large box trucks used in local and regional delivery are frequently covered, and this surprises many local fleet operators who assume the program targets only long-haul carriers. If a box truck has a manufacturer’s GVWR above 14,000 lbs, runs on diesel or an alternative fuel, and operates on California roads, it is generally covered. Our guide on box truck ELD requirements covers the federal ELD side separately; the two obligations are independent.

Heavy service and utility trucks, including large plumbing and HVAC service vehicles, crane trucks, and bucket trucks on California public roads, are typically covered as well. The nature of the work does not change the vehicle’s compliance status. The GVWR and fuel type do.

Refuse, Tow, and Waste Vehicles

Refuse trucks and garbage vehicles are almost universally above the 14,000 lb GVWR threshold and run on diesel or compressed natural gas, both of which are covered fuel types. Tow trucks capable of hauling heavy commercial vehicles are typically well above the threshold. Roll-off trucks, recycling vehicles, and portable toilet service trucks with large tank bodies on diesel chassis are generally covered as well.

Transit Buses, School Buses, and Motorcoaches

CARB includes transit, shuttle and school buses and motorcoaches when they meet the weight, fuel and California-road criteria. Public ownership alone is not an exclusion. Government operators should confirm the current reporting and fee instructions in CTC-VIS rather than assume a fee waiver.

Out-of-State Fleets Entering California

An out-of-state fleet must meet Clean Truck Check requirements for each covered vehicle it operates on California public roads. That ordinarily means CTC-VIS reporting, the annual fee and passing tests by the vehicle’s due dates. Registration in another state does not itself create an exemption; CARB’s limited five-day pass may be available to an eligible occasional entrant.

What Gross Vehicle Weight Rating Triggers Compliance?

The threshold is a manufacturer’s gross vehicle weight rating above 14,000 pounds. Almost all non-gasoline heavy-duty vehicles with a GVWR over 14,000 lbs that operate on California public roads must comply with Clean Truck Check.

GVWR is the manufacturer-assigned maximum loaded vehicle weight, not its actual scale weight on a particular trip. Check the manufacturer’s label or other authoritative vehicle documentation. A GVWR of exactly 14,000 pounds does not cross the Clean Truck Check threshold; a rating above 14,000 pounds may, if the other coverage conditions are met.

What If My Vehicle Is Right at the Threshold?

The rule uses the manufacturer’s GVWR, not an estimate, curb weight or weigh-station reading. Confirm the rating from the vehicle label or manufacturer documentation when it is close to 14,000 pounds.

Why Do So Many Vocational Trucks Clear This Threshold?

Vehicle class labels and typical weights are only clues. Do not infer coverage from a truck’s body style, axle count or a quoted class range. Check the manufacturer GVWR of each vehicle.

A box truck or service vehicle may fall on either side of the threshold. The manufacturer-assigned GVWR, not a model-family average, decides this part of the test.

Which Fuel Types Are Covered Under Clean Truck Check?

Covered powertrains include diesel, natural gas, propane, ethanol, methanol and other qualifying non-gasoline fuels, as well as hybrids using a covered combustion engine. A gasoline-only vehicle and a truly zero-tailpipe-emission battery-electric or hydrogen fuel-cell vehicle are not subject to Clean Truck Check. Confirm unusual dual-fuel configurations against CARB guidance.

CARB defines alternative fuel as natural gas, propane, ethanol, methanol, or any other non-diesel, non-gasoline fuel, including combinations of these fuels. Electricity, hydrogen, and other zero tailpipe emissions technologies fall outside that definition, which is why zero-emission vehicles are exempt from the program.

What About Vehicles That Run on Two Fuels?

A dual-fuel or hybrid vehicle is not exempt merely because it also uses electricity or gasoline. Determine whether its combustion engine uses a fuel covered by CARB’s definition, then apply the GVWR and California-road criteria. If the configuration is unusual, confirm it with CARB before marking it exempt.

Are CNG and LNG Trucks Covered?

Yes. Compressed natural gas (CNG) and liquefied natural gas (LNG) are both covered alternative fuels under the program. CNG refuse trucks, CNG transit buses, and LNG long-haul trucks are all covered if they meet the weight threshold. Switching to a cleaner fuel does not create an exemption. The test required depends on the engine model year, the same way it does for diesel trucks.

Which Vehicles Are Exempt From CARB Clean Truck Check?

The exemptions are specific and narrow. Clean Truck Check does not apply to:

• Zero-emission vehicles, including battery-electric trucks and hydrogen fuel cell trucks
• Military tactical vehicles designed and used for military tactical operations
• Authorized emergency vehicles that meet California’s specified statutory definitions; some may still need CTC-VIS reporting to resolve a DMV hold
• Historical vehicles that meet the California Vehicle Code’s historical vehicle definition
• Motorhomes registered outside of California
• Vehicles operating under a CARB-issued experimental permit
• Qualifying new engines certified to the optional 0.010 g/bhp-hr NOx standard, but only through December 31, 2026
• Certain out-of-state vehicles operating under a qualifying California emergency executive order or declaration for the limited period CARB specifies

California-registered motorhomes are covered, but on an annual rather than twice-yearly testing schedule.

Does Having an ELD Exemption Exempt a Fleet From Clean Truck Check?

No. A federal ELD exception does not create a Clean Truck Check exception. CARB regulates emissions compliance for covered vehicles operating on California roads; FMCSA’s ELD rule generally concerns drivers who must keep hours-of-service records. A short-haul driver may not need an ELD yet still operate a Clean Truck Check-covered vehicle. CDL licensing is separate again: the usual federal Class B weight threshold is 26,001 pounds, with other passenger and hazardous-material triggers. A vehicle can therefore exceed CARB’s 14,000-pound threshold without requiring its driver to hold a CDL on weight alone.

Is There an Exemption for Trucks That Rarely Enter California?

No general low-use or occasional-entry exemption applies. An eligible vehicle owner may instead request a five-day pass once per calendar year per vehicle before entering California, provided there is no outstanding enforcement action. A pass allows operation during its approved period but does not make a non-compliant vehicle compliant or qualify it for California DMV registration.

What Is the Time-Limited NOx Standard Exemption?

CARB describes a temporary exclusion for new vehicles with engines certified to the most stringent optional 0.010 g/bhp-hr NOx standard, ending January 1, 2027. CARB’s published FAQ stated that none had been certified as of June 2024; do not assume a particular vehicle qualifies without checking its engine certification with CARB.

What Type of Emissions Test Does Your Truck Need?

The test method depends primarily on the engine model year and fuel type, with the engine emissions-control label used to confirm the correct category. The program distinguishes OBD testing from non-OBD inspection procedures.

CARB generally assigns 2013-and-newer diesel and diesel-hybrid engines and 2018-and-newer alternative-fuel and alternative-fuel-hybrid engines to OBD testing. Older engines generally follow the applicable non-OBD procedure. Check the engine label and CARB’s testing guidance for an individual vehicle.

What Test Does an OBD-Equipped Vehicle Need?

OBD-equipped vehicles (2013 and newer diesel engines and 2018 and newer alternative fuel engines) require a scan of the engine’s on-board diagnostics data using a CARB-certified testing device. The scan reads emissions fault codes and readiness data directly from the engine and sends the results to CARB’s Clean Truck Check Vehicle Inspection System, known as CTC-VIS.

A periodic OBD test must use a CARB-certified device. A non-continuously connected scan-tool test is performed by a CARB-credentialed tester. With a CARB-certified continuously connected telematics device that submits testing data automatically, CARB says a separate credentialed tester is not required for that submission.

CARB’s current certified-device list names Pacific Track’s PT40 and PT40-Q as continuously connected OBD devices under EO IM-006-0001-7. Geosavi may offer a compatible service configuration, but CARB certifies the listed device, not every installation or fleet service. Confirm the vehicle’s OBD eligibility, diagnostic connector and protocol, supported hardware and software, active connectivity, enrollment, and CARB result submission with the provider before relying on it for a deadline. A connected device does not replace CTC-VIS reporting or the annual fee.

CARB’s approved OBD test submissions are for Clean Truck Check emissions compliance. Do not assume the same connected device’s separate ELD or telematics service has identical data collection or sharing rules; review the applicable provider terms and configuration.

What Test Does a Non-OBD Vehicle Need?

Under CARB’s testing guidance, covered vehicles with 2012-or-older diesel engines generally use the non-OBD procedure: a smoke-opacity test and visual inspection of emissions-control equipment. This program classification does not prove that no diagnostic electronics exist on the vehicle.

The smoke opacity test measures how much smoke the engine produces during acceleration, using a calibrated smoke meter. A vehicle that produces too much smoke must have the underlying issue repaired before it can pass. The visual inspection checks whether the vehicle’s emissions-related parts, including the exhaust system, air filter, and fuel system, are present, intact, and show no signs of tampering or damage. Both tests must be completed by a CARB-credentialed tester.

Alternative fuel vehicles with 2017 or older engines need the visual inspection only and are not required to take the smoke opacity test.

Quick reference by engine type:

Always check the model year on the engine’s emissions label, not the vehicle’s model year. A 2015 truck can have a 2012 engine if the powertrain was replaced. The engine year is what controls the test type.

Do Out-of-State Fleets Have to Comply With CARB Clean Truck Check?

Yes. If your heavy-duty truck operates in California, California’s Clean Truck Check requirements may apply even if your fleet is based in another state. The obligation applies to any vehicle operating on California public roads and highways, regardless of where it is registered.

For fleet operators in states that border California, including Arizona, Nevada, and Oregon, this has direct day-to-day implications. For operators in Texas, New Mexico, Utah, and other states whose trucks make periodic California runs, those vehicles carry California compliance obligations even when most of their operation happens elsewhere.

CARB confirmed on March 10, 2026, that requirements remain fully in effect for out-of-state vehicles, covering all four obligations: registering in CTC-VIS, paying the annual compliance fee, submitting passing emissions tests, and having no outstanding enforcement violations. This confirmation came after the EPA partially disapproved California’s State Implementation Plan. CARB made clear that the EPA’s action only affected whether those emissions reductions could count toward federal air quality targets. It had no effect on CARB’s authority to enforce the program against all vehicles operating in California.

How Does CARB Enforce Against Out-of-State Vehicles?

CARB says it uses roadside inspections, remote emissions monitoring devices and automated license plate readers, and coordinates with CHP. A specific vehicle’s compliance status should be checked in CTC-VIS; do not assume every screening event results in a citation.

An out-of-state vehicle may receive a CARB notice or enforcement action if it fails an applicable requirement. Follow the vehicle-specific notice and CARB instructions; the process is not a fixed automatic sequence.

What If My Fleet Only Enters California Occasionally?

CARB offers an approved five-day pass for an eligible vehicle once per calendar year, covering five consecutive days. The request must be submitted through CTC-VIS at least seven business days before planned entry, and the vehicle must have no outstanding enforcement action. Keep the approved pass in the vehicle. It permits operation during the approved period but does not make a non-compliant vehicle compliant or eligible for California DMV registration; ordinary reporting, fee and testing obligations remain the route to full compliance.

How Do Compliance Deadlines Work for Covered Vehicles?

Every covered vehicle has a compliance deadline. How that deadline is set depends on where the vehicle is registered. Both California-registered and out-of-state vehicles have the same compliance obligations. Only the method of calculating the deadline differs.

How Are Deadlines Set for California-Registered Vehicles?

California-registered vehicles generally have deadlines tied to the DMV registration expiration date and, for semiannual testing, another deadline about six months later. Starting October 1, 2027, OBD-equipped vehicles are scheduled for four tests per year. Always use the specific dates displayed in CTC-VIS; do not infer them from a simplified calendar rule.

How Are Deadlines Set for Out-of-State Vehicles?

For out-of-state vehicles, CARB generally assigns compliance months using the last VIN digit. Check the exact due dates in the vehicle’s CTC-VIS account; a quoted example or another vehicle’s schedule should not replace that record.

How Far in Advance Can a Passing Test Be Submitted?

CARB allows a passing test to be submitted up to 90 days before the applicable compliance deadline. Confirm that the passing result appears in CTC-VIS in time for that deadline.

How Often Is Testing Required Right Now and What Changes in 2027?

As of November 2026, most covered vehicles need two passing emissions tests per year. Qualifying agricultural vehicles and California-registered non-commercial motorhomes generally test annually. Use each vehicle’s CTC-VIS account for the actual due dates.

Starting October 1, 2027, OBD-equipped vehicles are scheduled for four tests per year. Non-OBD vehicles remain semiannual. Qualifying agricultural vehicles and California-registered non-commercial motorhomes remain annual, even if equipped with OBD. This future change does not make quarterly testing a current requirement.

Covered owners must report vehicles in CTC-VIS, pay the annual compliance fee and submit passing tests by the applicable due dates. CARB lists the fee as $32.13 for 2026 compliance deadlines and $33.12 for deadlines on or after January 1, 2027. Check CTC-VIS for each vehicle’s deadline and current status.

Who Is Responsible When a Vehicle Is Leased or Sold?

Compliance responsibility depends on ownership, lease terms and CARB’s transfer rules. Confirm the responsible party and vehicle status before operating or transferring a covered vehicle.

Who Is Responsible for a Leased Vehicle?

The company that owns and leases out the vehicle is responsible by default. This means registering in CTC-VIS, paying the annual compliance fee, and making sure passing tests are submitted. There is one exception: if the lease runs longer than one year and the lease contract formally states that the company or person leasing the vehicle takes on compliance responsibility, the obligation transfers to them for that lease period. If the contract says nothing about this, or if the lease is under one year, the owner remains responsible. Confirm this in writing before assuming either party has taken it on.

What Happens When a Used Vehicle Is Sold?

For a used vehicle, CARB says the buyer is responsible for ensuring the vehicle demonstrated compliance within the 90 days before transfer. Compliance status may transfer only if that condition is met. Verify the vehicle’s CTC-VIS status and the transaction requirements before closing; do not assume a sale erases a compliance problem or that every sale requires a new test.

What Are the Rules for Brand New Vehicle Purchases?

For a brand-new covered vehicle, CARB generally requires the ultimate purchaser to demonstrate reporting and fee compliance within 30 days of purchase; the first emissions test is due at the vehicle’s next scheduled testing deadline, subject to CARB’s rules. Confirm the vehicle’s CTC-VIS instructions rather than assume the same timing applies to a used sale.

What Are the Consequences of Non-Compliance?

Failure to report a covered vehicle, pay its annual fee, or submit a passing test by the applicable deadline can lead to enforcement and, for California-registered vehicles, a DMV registration hold. The response depends on the vehicle and the action CARB takes.

What Is the Enforcement Sequence?

CARB uses roadside inspections, remote emissions monitoring and other compliance checks. Non-compliance can lead to notices, enforcement action, a California DMV registration hold, or denial of entry to some ports and railyards. The sequence and consequences are not identical in every case. See CARB’s current FAQ and the notice issued for the specific vehicle; do not treat federal ELD inspection programs as Clean Truck Check enforcement rules.

What Are the Financial Penalties?

Civil penalties depend on the specific violation, current law and enforcement action. Do not assume a fixed daily amount applies to every non-compliant vehicle. Resolve any CARB notice promptly and follow its response instructions or obtain qualified legal advice.

What About DMV Registration Holds?

California DMV may place a registration hold on a subject California-registered vehicle that is not compliant with Clean Truck Check. Verify the specific reporting, fee, test or enforcement issue in CTC-VIS and follow CARB’s instructions; a DMV hold is not the same as an automatic roadside out-of-service order.

Federal HOS and ELD duties are separate from CARB emissions compliance. An ELD or CDL status does not establish Clean Truck Check coverage, and a CARB issue should not be described as an FMCSA Safety Measurement System violation. Our Clean Truck Check overview explains the California program in more detail.

Covered vs Exempt Vehicles: Quick Reference

The examples below assume California public-road use and the stated fuel type. A vehicle-body label alone does not establish coverage; confirm the manufacturer GVWR, powertrain and any CARB exclusion for each vehicle.

What Should You Ask Before Starting the Compliance Process?

What is the manufacturer’s GVWR on my vehicle’s door jamb label?

Read it from the label on the vehicle, not a spec sheet or registration document. If the number is above 14,000 lbs, continue through the rest of these questions. If it is 14,000 lbs or below, the vehicle is not covered.

What Fuel Type Does My Vehicle Run On?

Diesel, natural gas, propane, ethanol, and methanol are all covered under the program, including any combination of these fuels. Gasoline is not covered. Zero-emission vehicles running on electricity or hydrogen are not covered. If your vehicle runs on any of the covered fuels listed above, move to the next question.

What is the model year of my vehicle’s engine?

Check the emissions label on the engine itself, not the vehicle’s model year. A 2013 or newer diesel or a 2018 or newer alternative fuel engine requires an OBD scan. Older engines go through the smoke opacity or visual inspection process.

Does the vehicle operate on California public roads and highways?

If your vehicle operates exclusively on private property and never uses a public road, verify its status with your compliance team. The program covers vehicles on public roads and highways specifically.

Where is the vehicle registered?

California-registered vehicles use the DMV registration expiration date to set compliance deadlines. Out-of-state vehicles use the last digit of the VIN. Both groups carry the same obligations; only the deadline calculation differs.

Who is responsible for compliance if the vehicle is leased?

Read the lease contract. If the lease is under one year, the owner is responsible by default. If it runs longer than one year and the contract formally assigns responsibility to the operator leasing the vehicle, it transfers. If the contract says nothing, the owner remains responsible.

If I only send trucks into California occasionally, what are my options?

An owner of an eligible vehicle with no outstanding enforcement action may request one five-consecutive-day pass per calendar year through CTC-VIS at least seven business days before entry. Approval is not automatic. Carry the pass in the vehicle; it permits limited operation but does not confer full compliance or California DMV registration eligibility.

If I am buying a used heavy-duty truck, is it currently compliant?

For a used vehicle, verify that compliance was demonstrated within the 90 days before transfer and confirm current CTC-VIS status. Do not assume a non-compliant vehicle becomes compliant merely because ownership changes.

CARB Clean Truck Check FAQs

About Clean Truck Check Vehicle Applicability

My company is based in Texas. Do my trucks have to comply when they run into California?

Yes, if the Texas-registered vehicle is non-gasoline, has a manufacturer GVWR above 14,000 pounds, operates on California public roads, and is not otherwise excluded. Covered out-of-state vehicles must meet CTC-VIS reporting, annual fee and testing obligations; a limited five-day pass may be available to eligible occasional entrants.

Are concrete mixer trucks and dump trucks covered?

Usually, but check each vehicle. A concrete mixer or dump truck with a manufacturer GVWR above 14,000 pounds, a covered non-gasoline engine and California public-road operation is subject unless a specific exclusion applies. The test type depends on engine year and fuel.

Are CNG garbage trucks covered?

Yes. Compressed natural gas is a covered alternative fuel. A CNG refuse truck with a GVWR above 14,000 lbs that operates on California roads is covered under the same rules as a diesel truck. The test required depends on whether the engine has built-in OBD diagnostics, which is determined by the engine model year.

Does a vehicle need to be used for commercial purposes to be covered?

No. The program applies based on GVWR and fuel type, not whether the vehicle is used commercially. A California-registered personal vehicle with a GVWR above 14,000 lbs running on a covered fuel type is subject to the program.

Are school buses covered?

CARB includes school buses when they meet the manufacturer GVWR, covered-fuel and California-road criteria. Public or school-district ownership alone does not make an otherwise covered bus exempt.

Is there a weight above which the program definitely applies?

No weight alone guarantees coverage. A vehicle with a manufacturer GVWR above 14,000 pounds must also use a covered non-gasoline powertrain, operate on California public roads or highways, and not meet a specific exclusion. The CARB threshold is lower than the usual federal Class B CDL weight threshold of 26,001 pounds.

Does Clean Truck Check apply to vehicles that only drive through California without stopping?

Yes, for a covered vehicle. Driving through California on its public roads counts even if the vehicle makes no stop in the state; the vehicle still must meet the applicable requirements or hold an approved limited pass.

Does the program apply if I send one truck into California just a few times a year?

A covered occasional-use vehicle is not automatically exempt. If eligible, its owner may request a five-consecutive-day pass once per calendar year, at least seven business days before entry, with no outstanding enforcement action. The approved pass permits limited operation but does not make the vehicle fully compliant.

About Testing, Deadlines, and Your Obligations

My fleet has a mix of 2010 and 2018 diesel trucks. Do they get tested the same way?

Not necessarily by the truck model year alone. For this program, a covered vehicle with a 2010 diesel engine generally needs a smoke-opacity test plus visual inspection; one with a 2018 diesel engine generally needs an OBD test using a CARB-certified device. A credentialed tester performs a scan-tool test, while a certified continuously connected telematics device may submit results without a separate tester.

Can I use the OBD scanner from our shop to submit the Clean Truck Check test?

A standard shop scanner is not enough. A periodic test must use a CARB-certified OBD device; a non-continuously connected scan-tool test requires a CARB-credentialed tester. A CARB-certified continuously connected device can submit results automatically without a separate credentialed tester.

What changes in October 2027 and which of my trucks does it affect?

Starting October 1, 2027, OBD-equipped covered vehicles are scheduled for four tests per year, rather than the current two. Non-OBD vehicles remain semiannual; qualifying agricultural vehicles and California-registered non-commercial motorhomes remain annual even if OBD-equipped.

How do I find my compliance deadline if my trucks are registered in Arizona?

Out-of-state vehicles use the last digit of the VIN to determine deadlines. Each digit maps to a specific month, and twice-yearly deadlines fall six months apart from that base month. Your specific deadlines are visible in your CTC-VIS account once you have registered the vehicle.

Can I submit a passing test more than 90 days before my deadline?

No. A test submitted more than 90 days before the deadline does not count toward that compliance period. Plan your testing to fall within that 90-day window.

What happens if one of my trucks gets flagged at a California port for non-compliance?

A non-compliant vehicle may face a CARB enforcement action and may be denied entry to a port or railyard. The consequence depends on the facility and the vehicle’s status; consult the specific notice and CTC-VIS account rather than assume an automatic denial or fixed penalty.

If I sell a truck that is currently non-compliant, does the buyer take on the issue?

The buyer must confirm that the used vehicle demonstrated compliance within the 90 days before transfer for compliance status to carry over. Check CTC-VIS and the transaction requirements before closing; a sale does not automatically erase an unresolved compliance issue.

Conclusion

Clean Truck Check is a broad program. It covers concrete and cement operations, dump truck fleets, refuse and tow services, transit and school bus operations, local delivery, and heavy vocational equipment of all kinds. The rule is simple: if the truck has a manufacturer’s GVWR above 14,000 lbs, runs on diesel or a covered alternative fuel, and operates on a California public road, it is almost certainly covered. Where your fleet is based does not change that.

The out-of-state reach is what catches most operators off guard. Fleets in Arizona, Texas, Nevada, New Mexico, Utah, Oregon, and every other state whose trucks cross into California carry the same obligations as California-registered fleets. CARB confirmed in March 2026 that enforcement is fully active, and its screening infrastructure at border crossings, ports, and railyards is designed to identify out-of-state non-compliance.

Starting October 1, 2027, most OBD-equipped covered vehicles are scheduled to move from two tests per year to four, while CARB’s annual-testing exceptions remain. Confirm each vehicle’s exact schedule in CTC-VIS and whether a certified connected device or periodic test is the appropriate method.

Call us at (800) 261-4361 or schedule a call with our team and we can walk through how your fleet’s ELD and compliance setup fits alongside your California obligations.