The FMCSA regulations are the rulebook for running a commercial trucking operation in the United States. They are large and they change — but you don't need to memorize the code. You need to know which parts apply to you, what they require, and how to stay current. This guide gives you that map.
The FMCSA and the FMCSRs
The Federal Motor Carrier Safety Administration (FMCSA) is the agency within the U.S. Department of Transportation responsible for the safety of commercial motor vehicles. The rules it enforces — the Federal Motor Carrier Safety Regulations (FMCSRs) — live in 49 CFR Parts 350–399 and cover everything from who can drive to how vehicles are maintained and how long drivers can work.
Key parts of the regulations
- Part 382 — Controlled Substances & Alcohol Testing. Drug & alcohol program and the Clearinghouse.
- Part 383 — Commercial Driver's License Standards. CDL classes, endorsements, and disqualifications.
- Part 387 — Financial Responsibility. Minimum insurance levels for carriers.
- Part 390 — General. Applicability, USDOT registration, and accident recordkeeping.
- Part 391 — Qualifications of Drivers. The Driver Qualification File and medical standards.
- Part 392 — Driving of CMVs. Safe-operation rules drivers must follow.
- Part 393 — Parts & Accessories. Equipment standards for safe vehicles.
- Part 395 — Hours of Service. Driving limits and ELDs.
- Part 396 — Inspection, Repair & Maintenance. The annual inspection, DVIRs, and upkeep.
Registration & the numbers you need
- USDOT number — identifies your carrier for safety monitoring (required for most interstate CMVs).
- Operating authority (MC number) — required to haul regulated freight for-hire across state lines.
- MCS-150 biennial update — refresh the form behind your USDOT number at least every two years.
- UCR & BOC-3 — Unified Carrier Registration and a process-agent filing for interstate for-hire carriers.
What's new for 2026
Recent FMCSA activity has focused on enforcement and licensing integrity — including stepped-up English-language-proficiency enforcement, the non-domiciled CDL final rule, and Clearinghouse-driven CDL downgrades. For the full breakdown, read our 2026 FMCSA rule-changes roundup.
Interstate vs intrastate
The FMCSRs apply directly to interstate commerce. Most states have adopted the FMCSRs for intrastate carriers as well, sometimes with variations (such as minimum driver age or certain hours-of-service exceptions). If you operate within a single state, confirm your state's adopted version of the rules.
Staying current
- Monitor the Federal Register and FMCSA rulemaking announcements.
- Follow plain-English summaries (like the Fleetive blog) for what actually changes day to day.
- Review changes on a quarterly cadence and update your policies and files accordingly.
How Fleetive helps you keep up
Rules change, but the operational work stays the same: keep credentials current, vehicles inspected, and records audit-ready. Fleetive automates that day-to-day compliance — alerting you before driver and vehicle deadlines, and keeping every document in an audit-ready system — so when the regulations shift, you adapt from a position of order. Start with the complete DOT compliance guide.