California Truck Exhaust & Emissions Laws: A Driver’s Guide

Three rulebooks, not one

Drivers working the harbor get told a lot of half-remembered things about California emissions rules, usually by someone who heard them from someone else. Most of the confusion comes from mixing up three separate rulebooks that apply at the same time and answer to different people.

Federal law (EPA). Applies everywhere in the United States. Governs engine certification and makes it illegal to tamper with emissions control equipment.
California state law (CARB and the Vehicle Code). Applies to essentially any heavy-duty vehicle operating on a California public road, whether or not it is registered here. This is where Clean Truck Check lives.
The ports’ own rules (the Clean Truck Program). Apply only to trucks entering the marine terminals at the Port of Los Angeles and the Port of Long Beach. These are terms of doing business with the ports, not traffic law.

A truck can be perfectly legal on the 710 and still be unable to enter a terminal, because those are different questions. Keep them separate in your head and most of the confusion goes away.

This guide is written for drivers and dispatchers and reflects the rules as published in September 2026. CARB deadlines, fees, and program details change frequently. Verify anything that matters to your business against CARB and the ports directly before you rely on it.

Clean Truck Check: the one that catches everyone

Clean Truck Check is California’s heavy-duty inspection and maintenance program — the rough equivalent of a smog check, but for trucks. It is the rule most likely to affect a truck working the harbor, and the one drivers are most often caught out by.

Who it covers. Nearly all diesel and alternative-fuel heavy-duty vehicles with a gross vehicle weight rating over 14,000 pounds that operate on California public roads. That includes out-of-state trucks. It is not limited to California-registered vehicles, and it is not limited to drayage. Zero-emission vehicles, military and emergency vehicles, and certain new low-NOx engines are excluded.

What it requires. Two things, and they are separate: an annual compliance fee paid per vehicle, and periodic emissions compliance testing submitted by a CARB-credentialed tester. Testing became effective 1 October 2024, and all compliance deadlines on or after 1 January 2025 require a passing test on file. Tests can be submitted up to 90 days before the deadline.

How often. Most vehicles subject to the program are on a twice-a-year testing cycle in 2026. Beginning October 2027, OBD-equipped vehicles — 2013 and newer diesel engines, and 2018 and newer alternative-fuel engines — move to four times a year.

When your deadline falls. For California-registered vehicles, it is tied to the DMV registration expiration. Otherwise it is set by the last digit of the VIN. Look yours up rather than guessing; the digit-based schedule is not intuitive.

The fee. CARB published the 2025 compliance fee at $31.18 per vehicle, and the fee is indexed to rise annually with the California Consumer Price Index. Check the current year’s figure before you budget.

How it gets enforced — including on the 710

Two mechanisms, and the first one surprises people.

Roadside emissions monitoring devices. CARB operates remote sensing equipment that screens trucks as they drive past. You are not pulled over and you may never know it happened. If your vehicle is flagged, you receive a Notice to Submit to Testing and have 30 days to comply. The heavy freight corridors around the ports are exactly where this equipment earns its keep.
DMV registration holds. Non-compliant vehicles may be blocked from registering or renewing. For a California-registered truck this is the one with teeth — it does not fine you, it simply stops you working.

Practically: a truck with an illuminated check-engine light, a DPF lamp it has been ignoring, or an aftertreatment fault it has been living with is a truck that will fail its next Clean Truck Check. The warning light you are deferring and the compliance test you have coming are the same problem.

The ports’ Clean Truck Program

Separate from CARB, the Port of Los Angeles and the Port of Long Beach run their own Clean Truck Program for trucks entering the marine terminals. If you never enter a terminal, none of this applies to you. If you do, all of it does.

The Ports Drayage Truck Registry (PDTR). Every truck entering a marine terminal must be on it. Registration runs through the concession agreement process.
Model year. Since 1 October 2018, trucks newly registering for service at the Port of Los Angeles must be model year 2014 or newer. Older trucks already on the registry were allowed to remain until 31 December 2022.
The Clean Truck Fund rate. $10 per twenty-foot equivalent unit, set by both ports in March 2020 and collected since 1 April 2022. Zero-emission trucks are exempt, and low-NOx trucks registered in the PDTR by 31 December 2022 were granted an exemption through 31 December 2027.

Drivers do not pay the Clean Truck Fund rate. The Port of Los Angeles is explicit about this: the rate is paid by cargo owners or their agents on loaded containers moved by truck. If you are a driver being asked to pay it, that is not how the program works — report it to the Port.

What happened to Advanced Clean Fleets

This one is worth clearing up, because a lot of drivers still plan around a rule that is being repealed.

CARB’s Advanced Clean Fleets regulation would have forced drayage fleets onto zero-emission trucks on a fixed schedule, including a requirement that only zero-emission trucks could be newly added to the drayage registry. Enforcement of the drayage and high-priority fleet requirements was held off pending a federal waiver decision, and on 13 January 2025 CARB withdrew its waiver request to the EPA entirely.

CARB then moved to formally repeal the High Priority Fleet and Drayage Fleet provisions. As of September 2026 that repeal is pending at the Office of Administrative Law and has not yet been finally acted on.

What this means for you: the ACF zero-emission drayage mandate is not being enforced, and CARB has moved to remove it. It is not a deadline you need to be buying equipment against today. It is also not the same thing as the ports’ own model-year rules, which are still very much in force. If someone tells you that you need a battery-electric truck to work the harbor, they are describing a rule that was withdrawn.

Deletes and tampering: the short version

Removing a diesel particulate filter, blocking EGR, disabling SCR or the DEF system, or installing a tuner that alters the emissions calibration is illegal. This is not a grey area and it is not a matter of enforcement priorities.

California Vehicle Code § 27156 prohibits installing any add-on or modified part whose principal effect is to bypass, defeat, or render inoperative an emissions control system, unless the part carries a CARB exemption.
Health & Safety Code § 43016 lets the state board collect a civil penalty of up to $1,500 per violation of Vehicle Code § 27156.
Federal EPA penalties stack on top. California enforces its tampering prohibition independently of federal law, so a single truck can draw both.
Exposure is not limited to the owner. It reaches the shop that did the work, and in some circumstances the carrier or broker that dispatched the vehicle.

There is also a practical problem specific to this market. A deleted truck cannot pass Clean Truck Check, because the test looks at the OBD system and the aftertreatment. A truck that cannot pass Clean Truck Check eventually cannot register. And a truck that cannot register cannot work the port. The deleted-truck route does not end well here.

We will not delete, defeat, or tune around an emissions system, and we will not reinstall someone else’s delete. What we will do is fix the underlying fault properly — which is almost always what the truck actually needed.

Keeping a drayage truck out of trouble

The harbor duty cycle is genuinely hard on aftertreatment — long gate idles, short runs, and exhaust temperatures that rarely get high enough for long enough. That is a maintenance problem, not a reason to delete anything. What actually works:

Run the regen when the truck asks. A parked regen costs you forty minutes. A plugged DPF costs you a truck.
Do not let a solid lamp become a flashing one. The difference between those two is usually the difference between a cleaning and a replacement.
Treat a check-engine light as a compliance issue. It is one. Fix it before your test window, not after you fail.
Buy DEF you can account for and store it out of the sun. Contaminated or degraded DEF throws SCR faults that look like expensive hardware failures.
Get the DPF cleaned on a schedule rather than waiting for a derate. Ash accumulates whether or not you regen.
Keep your records. Test submissions, repair invoices, and DPF cleaning receipts are what you produce when someone asks.
Know your deadline. Look up whether yours runs off your DMV registration or your VIN’s last digit, and put it in a calendar.

If your truck is throwing aftertreatment faults, derating in gate queues, or heading toward a compliance test it will not pass, call (562) 261-8946. Fixing it properly is cheaper than the alternatives, and it is the only route that keeps the truck working.

Where to check the current rules

Everything above moves. Before you make a business decision on it, check the source:

CARB — Clean Truck Check requirements, deadlines, fees, and credentialed tester listings.
The Port of Los Angeles and the Port of Long Beach — Clean Truck Program, the Drayage Truck Registry, and the Clean Truck Fund rate.
California DMV — registration holds tied to emissions compliance.
Your carrier or your own compliance provider — for anything that turns on your specific fleet, registration state, or operating authority.

We are diesel mechanics, not a compliance service. We can tell you what is wrong with the truck and fix it. We cannot tell you what your fleet’s regulatory obligations are, and you should be suspicious of any shop that says it can.

General information only. This guide is written for drivers and dispatchers working the Port of Los Angeles and Port of Long Beach. Regulations change and every truck is different — when in doubt, follow your carrier's procedures, the current FMCSA and CARB regulations, the terminal operator's rules, and the instructions of law enforcement on scene.

California Exhaust Laws & Your Truck