California DOT regulations shape how commercial fleets operate on the state’s busy highways, and understanding the main rules keeps trucks rolling and fines at bay. This guide spotlights the key compliance pillars that matter most for carriers, safety managers, and owner-operators in California.
Federal vs. California Rules
Commercial carriers in California answer to both federal FMCSA regulations and state-specific programs run by the California Highway Patrol (CHP), Caltrans, and the Air Resources Board. Federal rules cover the usual suspects such as driver qualifications, hours of service, and vehicle maintenance, while California layers on its own inspection programs, identifiers, and emissions standards.
Interstate carriers must comply with FMCSA rules in Title 49 of the Code of Federal Regulations and also with California’s additional requirements when operating in the state. Purely intrastate carriers still follow large portions of the federal safety framework, plus California-specific mandates like the Basic Inspection of Terminals (BIT) program and state ELD adoption.
CA Number, MCP, and USDOT
To legally operate commercial vehicles in California, most motor carriers need a Motor Carrier Permit (MCP) from the DMV and a unique CA number issued under the state’s Motor Carrier Permit Program. As of recent years, California also expects carriers to obtain a USDOT number before enrollment, even if they operate only within state lines.
The carrier’s CA number or USDOT number must appear on both sides of each commercial vehicle as identification, in line with California Vehicle Code requirements. Out-of-state carriers that regularly cross into California may need both the USDOT number and a state MCP/CA number, depending on their operations and weight thresholds.
BIT Inspections and 90-day Checks
California’s Basic Inspection of Terminals (BIT) program is one of the defining parts of state DOT-style regulation. CHP uses BIT to review a carrier’s terminals, vehicles, and safety records, focusing heavily on maintenance documentation and defect repairs.
Under BIT rules, regulated vehicles must receive documented inspections at least once every 90 days, and carriers must keep those records for a minimum of two years. Terminals with strong safety histories can go several years between CHP BIT visits, while terminals with poor ratings face more frequent re-inspections and the risk of enforcement action.
Daily Inspections and Maintenance Records
Beyond the 90-day BIT cycle, California expects carriers to build a culture of daily inspections and preventive maintenance. Drivers are required to conduct pre-trip checks that look at brakes, lights, tires, steering, and overall vehicle condition, reporting any safety defects to the carrier.
Carriers must keep maintenance files that show inspection dates, repairs, and the identification of each vehicle, including license or unit numbers and the signature of an authorized representative. Poor documentation can be almost as damaging as poor maintenance, since missing or incomplete records can trigger citations or a downgraded terminal rating during a BIT review.
Hours of Service and California’s ELD Mandate
Like the rest of the country, California uses hours-of-service (HOS) rules to limit fatigue and keep tired drivers off the road. The state’s intrastate HOS framework historically differed from federal limits, but the structure still revolves around maximum daily driving time, total on-duty hours, and required off-duty periods.
The big recent change is California’s adoption of an intrastate electronic logging device (ELD) mandate effective January 1, 2024. Intrastate drivers who previously used paper records of duty status must now use approved ELDs to track HOS, unless they fall into limited exemptions such as certain short-haul drivers, driveaway-towaway operations, and older vehicles built before model year 2000.
Driver Qualification and Testing
California aligns closely with federal driver qualification rules, requiring appropriate commercial driver’s licenses and any needed endorsements for hazardous materials, passengers, or tank vehicles. Carriers must keep qualification files with items like medical certificates, driving history, and records of any required road tests or training.
DOT-regulated employers must also follow 49 CFR Part 40 for drug and alcohol testing, including pre-employment, random, post-accident, and reasonable suspicion tests for safety-sensitive drivers. California carriers that miss testing requirements or fail to remove drivers who test positive risk serious penalties and exposure in the event of a crash investigation.
Vehicle Size, Weight, and Safety Gear
Caltrans sets strict rules for vehicle size and weight on state roads. In general, commercial vehicles are limited to about 14 feet in height and 102 inches in width, with numerous special cases for certain configurations and routes. Weight rules follow the federal bridge formula but are applied through California-specific truck route designations and permits.
Safety equipment requirements include properly working lights, reflectors, fire extinguishers, and load securement that meets federal cargo rules. Carriers must also follow logbook and documentation rules related to trip records and safety placards, especially when hauling hazardous materials.
CARB Emissions and the Truck and Bus Rule
No discussion of California truck compliance is complete without emissions. The California Air Resources Board (CARB) Truck and Bus Regulation targets diesel vehicles that operate in California, pushing fleets toward cleaner engines and filters over time.
By January 1, 2023, nearly all diesel-powered trucks operating in the state were required to meet specific engine year or retrofit standards, and non-compliant vehicles can be blocked from registration. CARB also runs separate programs for zero-emission vehicles and idling limits, which add another layer of rules for fleets planning long-term operations in California.
Intrastate vs Interstate: Key Contrasts
The split between intrastate and interstate status changes how some rules apply, but not as much as many carriers assume. Interstate carriers must meet full FMCSA requirements and, when in California, still adhere to state mandates like CARB emissions and BIT inspections for applicable vehicles.
Intrastate carriers might benefit from slightly different HOS limits or exemptions but are still bound by driver qualification, inspection, and record-keeping requirements rooted in federal regulations. A frequent mistake is assuming intrastate status equals lighter regulation, which can set fleets up for citations during roadside inspections or CHP audits.
Penalties, Audits, and Risk Exposure
Non-compliance with California DOT-style regulations carries teeth. CHP and other enforcement agencies can place vehicles out of service, assess fines, and schedule re-inspections for terminals with poor safety performance.
From a liability standpoint, violations involving HOS, maintenance, or driver qualification can feature prominently in civil litigation after a crash. Plaintiffs’ attorneys often use BIT findings, inspection histories, and logbook data to argue that a carrier put profits ahead of safety, which can quickly turn a routine claim into a high-exposure case.
Building a Compliance Program
A strong compliance program turns these requirements into a repeatable system instead of a scramble every time CHP visits a terminal. Many California fleets invest in written policies, driver and mechanic training, and periodic internal audits that mirror BIT criteria and FMCSA guidance.
Telematics and fleet software can help monitor HOS, schedule 90-day inspections, track maintenance history, and keep an eye on emissions deadlines tied to CARB rules. For larger or fast-growing fleets, DOT compliance services with California trucking expertise can be a smart backstop against regulatory blind spots.
Your Trusted Partner for DOT Compliance
Running trucks in California is demanding work; keeping up with federal and state rules should not add to the stress. At Express Compliance, we step in as your back-office compliance partner, helping new and existing carriers launch, grow, and stay audit-ready from day one. From LLC formation and EIN setup to DOT numbers, MC authority, registrations, and permits, our team builds a solid legal and regulatory foundation around your operation.
Beyond startup filings, Express Compliance supports the full safety lifecycle with drug and alcohol testing programs, driver qualification file management services, hours-of-service support, and compliance audits tailored to FMCSA and DOT standards. You get guidance that ties together paperwork, safety programs, and everyday operations so your fleet can focus on moving freight instead of decoding regulations.
Get in touch with us today and turn complex DOT rules into a clear, confident game plan.
