If you run trucks in California, you live with two inspection clocks. One is federal and runs once a year. The other is state and runs every 90 days. Mix them up, or let one slide, and you risk out of service orders, fines, and a tough conversation with the CHP during a terminal inspection.
The good news is that both inspections reward the same habit: keeping your equipment in safe, road ready condition all year long. This guide explains the difference, what inspectors actually look at, and what this year's national roadside numbers tell us about where trucks fail.
The Two Inspections, Side by Side
The DOT annual inspection (federal)
Under federal rules (49 CFR 396.17), every commercial motor vehicle in interstate commerce, including trailers, must pass a periodic inspection at least once every 12 months. The inspection follows the standards in Appendix G of the Federal Motor Carrier Safety Regulations. A qualified inspector completes it, and you keep the report on file and carry proof on the vehicle.
Who needs it: trucks, tractors and trailers used in interstate commerce that meet the federal commercial motor vehicle definition. Many intrastate carriers follow it too, since California requires comparable inspections.
The 90 day BIT inspection (California)
California's Basic Inspection of Terminals program, known as BIT, is run by the California Highway Patrol. Under BIT, motor carriers must inspect each covered vehicle at least every 90 days and keep the records. During a terminal inspection, the CHP reviews your maintenance records, driver records and a sample of your vehicles.
Who needs it: most California motor carriers operating trucks and truck tractors with three or more axles, combinations, many trailers, and certain other commercial vehicles. If you are not sure whether your trucks fall under BIT, ask us or check with the CHP Motor Carrier Safety Unit.
The simple way to remember it
- DOT annual: once a year, federal standard, sticker or report on the vehicle.
- BIT 90 day: four times a year, California standard, records in your file for the CHP.
Many owners schedule them together. The annual inspection can line up with one of the four 90 day inspections, which saves downtime and keeps your paperwork clean.
What Inspectors Look At
Both inspections focus on the systems that keep a heavy vehicle safe:
- Brakes: adjustment, linings, drums and rotors, air lines, chambers, compressor, governor and air leakage.
- Tires and wheels: tread depth, cuts, bulges, inflation, cracked wheels and loose lug nuts.
- Lights and reflectors: every lamp working, correct color, reflective tape in good condition.
- Steering and suspension: play in the steering, worn kingpins, cracked springs, loose U bolts.
- Frame and coupling: cracks, fifth wheel condition, kingpin, safety chains on trailers.
- Exhaust and fuel systems: leaks, secure mounting, nothing that could put exhaust into the cab.
- Windshield, wipers, mirrors and horn.
Our DOT and 90 day BIT inspection service covers each of these items and documents the results so you are ready for a CHP visit.
What the 2026 Roadside Numbers Tell Us
Every year, the Commercial Vehicle Safety Alliance runs International Roadcheck, a 72 hour inspection blitz across North America. The 2026 results are a clear map of where trucks fail.
- Inspectors completed 54,575 driver and vehicle inspections.
- 10,350 commercial vehicles were placed out of service. That is close to one in five.
- Brakes were the top vehicle problem, making up 39.1 percent of vehicle out of service violations.
- Tires came second at 20.9 percent, followed by cargo securement at 12.4 percent and lighting at 11.9 percent.
Here is the insight most owners miss: brakes, tires and lights together account for most out of service orders, and all three are things a good 90 day inspection catches. The trucks that get parked at the roadside are often trucks that skipped or rushed their routine inspections.
There is a positive side too. Roughly four out of five vehicles inspected had no critical violations. Staying on a disciplined inspection schedule is how you stay in that group.
How to Pass the First Time
- Walk the truck before the inspection. Check every light, look at every tire, and listen for air leaks with the engine off and brakes released.
- Fix brake adjustment issues early. Out of adjustment brakes are one of the most common violations. Automatic slack adjusters still need checking. Our air brake repair service handles adjustment, chambers, valves and air system leaks.
- Replace worn tires before they become a violation. Steer tires have stricter tread requirements than drive and trailer tires. See our tire repair service.
- Keep your paperwork organized. For BIT, the CHP looks at records as closely as trucks. Keep every 90 day report, repair order and driver inspection report together and easy to find.
- Do not forget trailers. The search term "DOT trailer inspection" is popular for a reason. Trailers need inspections too, and they are easy to overlook.
Looking Ahead: Where Inspections Are Going
Inspection programs are getting more data driven. Roadside inspectors increasingly use electronic screening, and California is already layering emissions checks on top of safety checks through the Clean Truck Check program. Starting in October 2027, OBD equipped heavy duty vehicles will move to emissions testing four times a year.
Our prediction: owners who combine safety inspections, emissions testing and preventive maintenance into one scheduled visit will spend less time off the road than owners who handle each requirement separately. That is exactly how we set up recurring service for our fleet customers. Learn more in our guide to Clean Truck Check going quarterly in 2027 and on our preventative maintenance page.
Why Fleets Choose Rapid Diesel for Inspections
Rapid Diesel Repair holds full state and federal DOT certifications and California CARB emissions compliance certifications. For more than 10 years, we have helped Inland Empire owner operators and fleets stay legal and on the road. If your truck needs repairs to pass, we fix it in the same shop, so you are not bouncing between vendors.
We are at 251 Kettering Dr in Ontario, CA, serving Rancho Cucamonga, Upland, Chino, Fontana, Pomona and nearby cities.
Call (909) 701 8755 to schedule your DOT or BIT inspection.
Frequently Asked Questions
What is the difference between a DOT inspection and a BIT inspection? A DOT annual inspection is a federal requirement done at least once every 12 months. A BIT inspection is a California requirement done at least every 90 days, with records kept for the CHP.
Do trailers need a DOT inspection? Yes. Trailers used in commercial operation need periodic inspections and should be included in your 90 day BIT schedule.
What fails DOT inspections most often? In the 2026 International Roadcheck, brakes were the top vehicle out of service violation at 39.1 percent, followed by tires at 20.9 percent.
Can I combine my DOT annual and 90-day BIT inspections? Yes. Many owners line up the annual inspection with one of their four 90 day inspections to save time.
Where can I get a DOT inspection near me in the Inland Empire? Rapid Diesel Repair in Ontario, CA. Call (909) 701 8755.
Why This Matters For Your Vehicle
A service decision affects more than the part being repaired. It affects your next trip, your operating costs and the time your vehicle is available. Keep inspection records, follow the engine and chassis manufacturer’s service schedule, and explain when each symptom appears. A diagnosis based on actual test results helps you compare repair options and plan maintenance before a small concern becomes a larger interruption.
Written by the Rapid Diesel Repair team, Ontario, CA. Serving the Inland Empire for more than 10 years with DOT and CARB certified diesel repair.