Fleet & DOT Compliance Guide

Complete compliance requirements for commercial motor vehicles and fleet management

Last updated: March 13, 2026

Introduction

This guide covers DOT compliance requirements for commercial motor vehicles (CMVs) with a GVWR over 10,001 lbs operating in interstate commerce. Whether you're a fleet manager or owner-operator, these are the basics you need to pass inspections and protect your CSA score.

Most violations happen because drivers don't know what inspectors check. From fire extinguishers to DOT numbers, we'll walk through each requirement. For vehicle-specific extinguisher sizing and product recommendations, see our DOT fire extinguisher buying guide.

Quick Compliance Checklist

Before any inspection, make sure you have:

Fire extinguisher: UL-rated 5 B:C minimum (10 B:C for hazmat), securely mounted, gauge in green
Warning devices: 3 reflective triangles or 6 fusees
DOT number on both sides of truck
Annual inspection sticker (less than 12 months old)
Registration, insurance, permits in the cab
Hazmat placards if you're hauling placardable quantities
First aid kit (recommended, sometimes required)
Current logbooks or working ELD

Fire Extinguisher Requirements

Every commercial vehicle needs a fire extinguisher. Here's what 49 CFR §393.95 requires:

Fire extinguisher pressure gauge diagram showing three zones: RECHARGE (red), READY (green), and OVERCHARGED (red), with two failure examples — needle in recharge zone and a cracked gauge

Check the gauge during every pre-trip inspection — needle must be in the green READY zone

Standard Vehicles

For regular trucks (not hauling hazmat):

One extinguisher rated 5 B:C or higher, OR
Two extinguishers each rated 4 B:C or higher
Must be UL-listed — the UL rating (e.g. 1-A:10-B:C) determines compliance, not the weight
ABC dry chemical is the standard choice — covers Class A, B, and C fires in one unit
No water extinguishers (they freeze)

Hazmat Vehicles

For hazmat loads:

Minimum 10 B:C rating required
Must be compatible with what you're hauling
Some hazard classes need higher ratings

Mounting Requirements

Mount it securely so it doesn't bounce around
Easy to reach (usually in the cab)
Pressure gauge must be visible
Protect from weather if outside

Fleet Best Practice

Most fleets standardize on 5 lb or 10 lb ABC extinguishers — both exceed the 5 B:C minimum and handle most fire types. A 2.5 lb ABC unit (rated 1-A:10-B:C) also meets the federal minimum and works well for pickups and service vehicles. Check pressure during every pre-trip inspection. See our DOT fire extinguisher guide for vehicle-specific sizing and NFPA 10 for service intervals.

Emergency Equipment

Besides fire extinguishers, you need warning devices for breakdowns:

Warning Devices

Pick one option:

Three reflective triangles (most common), OR
Six fusees or three liquid flares

Bird's-eye diagram showing reflective triangle placement behind a stopped truck: 10 feet, 100 feet, and 200 feet from the rear of the vehicle on a highway shoulder

Triangle placement per 49 CFR §392.22 — place at 10 ft, 100 ft, and 200 ft behind the vehicle

Note: Can't use flares if you're hauling explosives or flammable cargo. Triangles are safer and work in all weather.

First Aid Kits

Not federally required for all CMVs, but many carriers mandate them and OSHA requires them if you have employees. ANSI/ISEA Z308.1 defines minimum contents for compliant kits — a Class A kit is the recommended baseline for commercial vehicles.

School bus requirements are state-specific and typically reference ANSI Z308.1. Most states require a 24-unit kit for standard buses and a 16-unit kit for smaller vehicles, mounted in an accessible location.

Check expiration dates during monthly inspections and restock after any use.

Hazmat Equipment

For hazmat loads, you also need:

Spill cleanup kit matched to what you're hauling
Absorbent materials
Personal protective equipment (PPE)
Emergency response guidebook
Shipping papers with emergency contacts

Vehicle Marking & Placarding

DOT Number Display

Per 49 CFR §390.21:

Both sides of the truck
At least 2 inches tall
Contrasting color from the truck
Format: "USDOT 1234567"
Readable from 50 feet away
Permanent (decals or paint, not magnetic signs)

Diagram showing USDOT number placement on a semi-truck cab door with callouts for minimum 2-inch height, contrasting color, and 50-foot readability requirements

DOT number placement per 49 CFR §390.21 — both sides, 2 in. minimum, contrasting color

Hazmat Placards

When hauling hazardous materials:

Required when hauling placardable quantities
Diamond shape, at least 10.8 inches per side
All four sides of truck/trailer
Match the hazard class of what you're carrying
Four-digit UN number for some loads
Remove or cover them when empty

Three-quarter view of a box truck showing hazmat placard positions on front, side, and rear with callout showing 10.8-inch minimum diamond size and UN number 1203

Hazmat placards required on all four sides — 10.8 in. minimum per side

All safety signage should meet ISO 7010 standards for clear communication.

Inspection & Maintenance Schedule

Here's what you need to check and when:

Top-down diagram of a semi-truck showing the 8-step pre-trip walkaround inspection path: cab controls, front lights, driver-side fuel and tires, coupling, trailer sides, rear lights, passenger side, and fire extinguisher

Standard pre-trip walkaround — complete all 8 stops before every trip

Inspection Type	Frequency	Key Items
Pre-Trip	Before each trip	Lights, tires, brakes, fire extinguisher gauge and mount, leaks
Post-Trip	After each trip	Damage documentation, DVIR completion
Monthly Safety Check	Monthly	Emergency equipment inventory, warning devices, documentation
Annual DOT Inspection	12 months	Full vehicle inspection per 49 CFR §396.17
Fire Extinguisher Service	12 months	Weight check, discharge test, inspection tag update

Fire Extinguisher Maintenance

Per NFPA 10:

Pre-trip (daily): Check gauge, verify secure mount, look for visible damage
Annually: Professional inspection by a certified technician
Every 6 years: Internal exam for stored pressure types
Every 12 years: Hydrostatic test for dry chemical units
Immediately: Replace if the gauge reads low or the unit is damaged
Keep records: Save all inspection tags and service paperwork

Documentation Requirements

Keep these documents ready for inspections:

Vehicle Documents

Must be in the truck:

Current vehicle registration
Proof of insurance
Annual inspection certificate
IFTA credentials (interstate fuel tax)
Overweight/oversize permits (if needed)
Hazmat shipping papers (if hauling hazmat)

Driver Documentation

Valid CDL
Medical certificate (DOT physical)
Hours of service logs (paper or ELD)
Driver qualification file (your carrier keeps this)
Hazmat endorsement (if needed)
TWIC card (for ports)

Maintenance Records

Annual inspection reports (keep for 14 months)
Fire extinguisher service records
Driver vehicle inspection reports (DVIR)
Repair and maintenance logs
Pre-trip/post-trip checklists
Equipment certification papers

Common Violations & How to Avoid Them

These are the violations inspectors catch most often. Each adds CSA (Compliance, Safety, Accountability) points to your carrier score — higher scores trigger more frequent inspections and can affect insurance rates.

Violation	CSA Points	How to Prevent
Fire extinguisher missing or discharged	4 points	Check gauge during pre-trip, mount securely
No warning devices	2 points	Keep triangles in the cab, check during pre-trip
DOT number wrong size or faded	1 point	Must be 2 inches tall and readable from 50 feet
Expired annual inspection	4 points	Track expiration dates, schedule 30 days early
Missing or wrong placards	3–10 points	Match placards to shipping papers, all 4 sides

Out-of-Service Violations

These violations mean the vehicle cannot move until fixed — and they hit your CSA score hardest:

Fire extinguisher completely missing
Brake problems that meet out-of-service criteria
Hazmat violations that create immediate danger
Hours of service violations past the limit
Missing or expired medical certificate

State-Specific Requirements

Federal DOT rules are the baseline, but some states add their own:

California

BIT inspection program
Stricter exhaust smoke limits than federal
Extra permits for hazmat on certain routes
CalOSHA rules if you have employees

New York

Enhanced inspection program for some fleets
Special permits for high-quantity hazmat
Extra paperwork for overweight permits
Tire chains required in winter on some roads

Texas

State-specific registration and permits
Oversized load rules change by route
Weight stations work differently
Texas environmental rules for hazmat

Interstate Operations

When you cross state lines, you need to follow federal rules plus the strictest state rules you'll hit. Check each state's requirements before you go.