DOT maintenance file requirements: proof the equipment is safe
The equipment rules say what must be on the truck and in working order. The maintenance file is how you prove it, one vehicle at a time.
Written by Inely Baez
The maintenance rules in numbers
DOT maintenance file requirements come from 49 CFR 396.3: for each vehicle you control for 30 consecutive days, keep its identification, a way to show what inspection and maintenance is due and when, and a dated record of the work, kept for 1 year and for 6 months after it leaves your control.
An auditor can't see how well a truck was maintained last spring. They can only see the record of it: the due date, the defect report and its repair, the annual inspection report.
I lead operations at Simplex, and as a CPA I read a maintenance file the way I read a ledger. Every entry needs a date, a rule behind it, and a record that matches.
The full briefing, read aloud
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Generated with AI text-to-speech from this article's key insights, in order, rather than reading it word for word. Chapter times come from a transcript of the audio. The article itself was written and reviewed by Inely Baez.
Key takeaways
The equipment standard is Part 393
Required equipment must be maintained to the performance and design criteria in the FMCSRs, and Part 393 sets most of them.
Maintenance has to be systematic
Every carrier must inspect, repair, and maintain all the vehicles it controls, not only fix what breaks.
Each vehicle needs its own file
Identification, due dates, and a dated work record, kept 1 year and 6 months after the vehicle leaves your control.
Every report runs on its own clock
Annual inspection reports 14 months, defect DVIRs 3 months, roadside reports certified in 15 days and kept 12 months.
2026 trimmed the rules
Spare fuses and liquid-burning flares left the emergency equipment rule, and roadside reports go back to a state only if it asks.
In this articleContents
What do DOT regulations require for equipment maintenance?
Three rules work together. Under 49 CFR 390.3(e)(3), all motor vehicle equipment and accessories required by the regulations must be maintained in compliance with all applicable performance and design criteria in the Federal Motor Carrier Safety Regulations. Part 393 sets most of those criteria.
Under 49 CFR 393.1, no carrier may operate a commercial motor vehicle unless it is equipped as Part 393 requires. Under 49 CFR 396.3(a), every carrier must systematically inspect, repair, and maintain all vehicles it controls, and keep parts and accessories in safe and proper operating condition at all times. That duty reaches beyond Part 393, naming frames, suspension systems, axles, wheels and rims, and steering systems. And under 49 CFR 396.7, a vehicle may not be operated in a condition likely to cause an accident or a breakdown.Which vehicles do the rules cover?
Part 393 applies to commercial motor vehicles as defined in 49 CFR 390.5. In interstate commerce, that means a vehicle rated or weighing 10,001 pounds or more, one designed or used to carry more than 8 passengers (driver included) for compensation or more than 15 without, or one hauling placarded hazardous materials. Part 396 does not apply to covered farm vehicles. Extra equipment is allowed under 49 CFR 393.3, as long as it doesn't decrease the vehicle's safety.What safety equipment does the DOT require on a truck?
The DOT requires the equipment in Part 393, Parts and Accessories Necessary for Safe Operation. It is organized by system, and each subpart sets the minimum standard your maintenance has to hold.
| Subpart | What it covers | One rule to know |
|---|---|---|
| B | Lamps, reflective devices, and wiring | Required lamps must work at all times and not be obscured (393.9) |
| C | Brakes | All brakes on the vehicle must be capable of operating at all times, with narrow exceptions (393.48) |
| D and E | Glazing, windows, and fuel systems | Fuel tanks, CNG containers, and LPG systems each have their own section (393.67 to 393.69) |
| F | Coupling devices and towing | Every fifth wheel must have a locking mechanism (393.70) |
| G | Tires, mirrors, horn, wipers, exhaust, seats, and more | Steer tires need 4/32 inch of tread, other tires 2/32 inch (393.75) |
| H | Emergency equipment | A fire extinguisher and warning devices on every power unit (393.95) |
| I | Cargo securement | Tiedowns, working load limits, and rules for specific commodities |
| J | Frames, cab and body, wheels, steering, suspension | The frame must not be cracked, loose, sagging, or broken (393.201) |
What emergency equipment is required now?
Each truck, truck tractor, and bus needs a fire extinguisher rated 5 B:C or more, or two rated 4 B:C or more (one rated 10 B:C or more when hauling placarded hazmat). It also needs three bidirectional reflective triangles or at least 6 fusees. Two items left the rule in 2026. Spare fuses stopped being required on April 20, 2026, and liquid-burning flares were removed on March 23, 2026. Our DOT fire extinguisher guide covers ratings and mounting.What are the DOT maintenance file requirements?
DOT maintenance file requirements start with 49 CFR 396.3(b). For each vehicle you control for 30 consecutive days, keep three things: its identification, a means to show the nature and due date of each inspection and maintenance task, and a record of inspections, repairs, and maintenance with their dates and nature.
Keep those records where the vehicle is housed or maintained, for 1 year, and for 6 months after the vehicle leaves your control. The rest of Part 396 adds records with their own clocks.| Record | Rule | Keep it |
|---|---|---|
| Vehicle ID: company number if marked, make, serial number, year, and who furnished it if you don't own it | 396.3(b)(1) | 1 year, plus 6 months after the vehicle leaves your control |
| Schedule showing the nature and due date of each inspection and maintenance task | 396.3(b)(2) | Same as above |
| Dated record of inspections, repairs, and maintenance | 396.3(b)(3) | Same as above |
| Annual inspection report | 396.21 | 14 months, where the vehicle is housed or maintained, plus proof on the vehicle |
| DVIRs that list defects, with the repair and driver-review certifications | 396.11 | 3 months |
| Roadside inspection reports, certified as corrected | 396.9(d) | 12 months |
| Annual inspector and brake inspector qualifications | 396.19, 396.25 | While they do the work, plus 1 year |
What changed in 2026?
- Tire size is out. Since July 21, 2026, the vehicle identification in 396.3(b)(1) no longer includes tire size (91 FR 45653).
- Roadside reports stay with you. Since July 22, 2026, you return a certified roadside report to the state only if it asks. You still keep a copy for 12 months (91 FR 37053).
- Electronic DVIRs are explicit. Since March 23, 2026, 396.11 and 396.13 state that the reports may be created and kept electronically (91 FR 7893).
Who is responsible: the driver or the carrier?
Both, at different points in the day. The driver checks and reports; the carrier repairs, certifies, and keeps the records.
What the driver does
- Before driving, be satisfied that 11 items are in good working order under 49 CFR 392.7: service brakes and trailer brake connections, parking brake, steering, lights and reflectors, tires, horn, wipers, mirrors, coupling devices, wheels and rims, and emergency equipment.
- Review the last DVIR if it listed defects, and sign it (396.13).
- At the end of each day's work, report any defect in writing for each vehicle driven (396.11).
- Hand a roadside inspection report to the carrier at the next terminal, or send it right away if you won't reach one within 24 hours (396.9).
What the carrier does
- Repair any reported defect likely to affect safety before the vehicle runs again, and certify the repair or that none was needed (396.11).
- Correct roadside violations and certify them within 15 days of the inspection (396.9).
- Never let a vehicle declared out of service move until the required repairs are done (396.9).
How do inspectors and auditors check your maintenance?
Inspectors check the vehicle at roadside; auditors check the file. Both show up under the Vehicle Maintenance BASIC in FMCSA's Safety Measurement System.
At roadside, each violation carries a severity weight from 1 to 10 in SMS Appendix A. A steer tire below 4/32 inch weighs 8. No or inadequate DVIR, or no proof of a periodic inspection, weighs 4. An inoperable required lamp or missing warning devices weigh 2. Our guide to CVSA inspection levels explains how roadside inspections work. In an investigation, the file itself is on trial. Failing to keep minimum maintenance records (396.3(b)), using a vehicle not periodically inspected (396.17(a)), and failing to require DVIRs (396.11(a)) are critical violations, which FMCSA ties to breakdowns in management controls. Running a vehicle declared out of service before repairs, or not fixing out-of-service defects a driver reported, are acute violations. For new carriers, see what the new entrant safety audit checklist covers.How to build a DOT maintenance file that holds up
Each step turns one part of the rule into a routine with an owner.
Step 1: Open a file for every unit, trailers included
A trailer is a motor vehicle under 390.5, and 396.17 requires each vehicle in a combination to pass its own annual inspection. List tractors, trailers, and converter dollies, with who furnished any unit you don't own.Step 2: Put the due dates in the file
Section 396.3(b)(2) wants a means to show what is due and when. A schedule with dates for every unit meets it; memory doesn't.Step 3: Close every report on time
Certify DVIR repairs before the vehicle runs again, and roadside corrections within 15 days. File both with the unit.Step 4: Keep the annual inspection on paper and on the truck
Keep the report for 14 months and put proof on the vehicle, such as a copy of the report or a sticker based on it. A qualifying state periodic inspection counts.Step 5: File the inspectors' qualifications
Keep evidence for whoever performs annual inspections or brake work, while they work for you and for 1 year after. It isn't needed for inspections done under a state program, or for air brake inspections by someone who passed the CDL air brake tests.Step 6: Audit the file on a schedule
Pick a few units each month and trace every record back to the rule. Our DOT safety compliance team and compliance programs can run that review with you, including mock audits.How Simplex helps you keep a maintenance file that holds up
The equipment, the records, and the audit all have to agree. We help with each one.
Equipment and maintenance compliance
Our DOT safety compliance services cover fleet equipment maintenance and repairs compliance, alongside driver files and hours of service.
Ready for the safety audit
Our audit guidance and support walks you through what FMCSA reviews, including maintenance and inspections.
A program that keeps checking
Our compliance programs include CSA monitoring and mock audits, so gaps in the file show up before an auditor finds them.
Frequently asked questions
All motor vehicle equipment and accessories required by DOT regulations shall be maintained in compliance with what?+
What goes in a DOT vehicle maintenance file?+
How long do you keep DOT maintenance records?+
What safety equipment does the DOT require on a truck?+
Do trailers need their own maintenance records?+
Where this information comes from
The requirements below come from federal regulation, the Federal Register, and FMCSA's Safety Measurement System, checked on September 24, 2026.
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1
eCFR — 49 CFR 390.3
Required equipment must be maintained to the performance and design criteria in the FMCSRs.
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2
eCFR — 49 CFR Part 393
The equipment standard: lamps, brakes, tires, emergency equipment, cargo securement, frames, and more.
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3
eCFR — 49 CFR 396.3
Systematic inspection, repair, and maintenance, and the records each vehicle file must hold.
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4
eCFR — 49 CFR Part 396
Roadside reports, DVIRs, the annual inspection, inspector qualifications, and retention periods.
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5
Federal Register — Completed Inspection Report Disposition
Roadside reports go back to the state only if it requests them, effective July 22, 2026.
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6
Federal Register — Spare Fuses
The spare fuse requirement removed, effective April 20, 2026.
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7
Federal Register — Liquid-Burning Flares
Liquid-burning flares removed from the warning device rules, effective March 23, 2026.
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8
FMCSA — SMS Methodology Appendix A (v3.21)
Severity weights for maintenance violations, and the acute and critical violations list.
Written by
Inely Baez
Chief Operating Officer, Simplex Group
Chief Operating Officer at Simplex Group, with nearly eight years at the company leading operational strategy and execution across compliance, technology, logistics, and performance systems. She is a Certified Public Accountant with a background spanning operations and finance, including leadership roles within Simplex's Freight 4 U division and Velox Transport Solutions. Her work focuses on building scalable, disciplined systems that support long-term performance and growth.
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The file is the proof your equipment is safe
Inspectors check the truck. Auditors check the file. Both are looking for the same thing: equipment kept to Part 393, with dated records to show it.
If you want a second set of eyes on your vehicle files before an auditor looks at them, talk to our team.