DOT Compliance Services Houston

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Houston trucking companies follow FMCSA safety rules for interstate work and the Texas version of those rules for trucks that stay in the state.

Our Houston office helps carriers set up and keep the records both require, from driver files and drug testing to hours of service and vehicle inspections, so they are ready for a DOT audit.

Which DOT rules apply to a Houston trucking company?

The federal rules apply when you run a commercial motor vehicle in interstate commerce. Under 49 CFR 390.5T, that is a vehicle of 10,001 pounds or more, one that carries more than 8 passengers (including the driver) for pay or more than 15 without pay, or one hauling hazardous materials in placarded amounts.

Those carriers need a USDOT number, and FMCSA lists Texas among the states that also require one from intrastate commercial vehicle registrants. The number must be displayed on your trucks, as our guide on how to mark a commercial motor vehicle explains.

A Houston-only load can still be interstate

Staying inside Harris County does not make a load intrastate. The federal definition of interstate commerce includes transportation between two places in one state “as part of trade, traffic, or transportation originating or terminating outside the State or the United States.” An import container moving from the Bayport terminal to a warehouse in Katy can fall under the federal rules even though the truck never leaves the metro area.

Texas rules in short

A carrier that runs only in Texas registers with TxDMV when it operates a vehicle over 26,000 pounds, hauls placarded hazmat, carries more than 15 passengers, or moves household goods for pay. It needs a USDOT number registered as intrastate first, and it must certify that it follows FMCSA drug-testing rules.

For those trucks, Texas DPS applies the federal safety rules with a few exceptions, set in 37 TAC 4.12:

RuleInterstate (federal)Texas only
Minimum driver age2118, with a Texas CDL
Daily driving limit11 hours within a 14-hour window, after 10 hours off12 hours, and none after 15 hours on duty, after 8 hours off
Weekly on-duty limit60 hours in 7 days, or 70 in 8 days if the carrier runs every day70 hours in 7 days, with a 34-hour restart
Federal limits from 49 CFR 391.11 and 395.3; Texas intrastate limits from 37 TAC 4.12.

Texas-only drivers also need an ELD unless an exemption applies. Our Texas DOT compliance page covers the state rules in full, and our Texas commercial driver handbook guide explains the state CDL tests.

What makes DOT compliance in Houston different?

The port and the petrochemical industry. Much of Houston’s truck freight is short-haul work tied to the Ship Channel, and the port adds its own requirements on top of FMCSA’s.

  • Port Houston: a record 4,303,345 TEUs in 2025, with about 2.5 million trucks served. Port Houston calls the Houston Ship Channel by far the nation’s largest port for waterborne tonnage, and its 2025 growth in chemical tankers and bulk cargo reflected demand for petrochemicals, crude oil, and plastics.
  • Short trips: a 2020 TxDOT study found that 75 to 80% of daily truck trips at the Barbours Cut, Bayport, and Jacintoport terminals start or end within about 15 miles of them.

What Port Houston expects at the gate

Before you pull a container, Port Houston’s terminal gate process expects current UIIA information and an approved SCAC code, every truck registered in LYNX, a valid TWIC card for every driver, and approval for hazardous cargo before it enters the terminal. Our Houston commercial truck insurance page explains the UIIA coverage behind that gate check.

Heavier container loads near the port

TxDMV issues an annual Intermodal Shipping Container Port Permit for containers moved within 30 miles of Bayport, Barbours Cut, the Port of Houston at IH 610, or Freeport. It allows up to 93,000 pounds on six axles or 100,000 pounds on seven, with set axle spacing. The permit does not cover the interstate highway system or hazardous materials.

Do Houston trucks need an annual DOT inspection?

Yes. Under 49 CFR 396.17, every commercial motor vehicle, including each trailer in a combination, must pass an inspection at least once every 12 months, with proof of it carried on the vehicle. Intermodal equipment providers must inspect the chassis they interchange to you.

You can do the inspection yourself or hire a garage, truck stop, or similar business with facilities for commercial vehicle inspections. Either way, the inspector must be qualified through a federal or state training program or at least a year of relevant training or experience, and you keep proof of that qualification (49 CFR 396.19). Check those credentials before you hire a mobile inspector.

Texas adds its own check. Safety inspections for non-commercial vehicles ended on January 1, 2025, but Texas DPS still requires every commercial vehicle, in every county, to pass a state safety inspection.

What does FMCSA check in a new entrant safety audit?

Five sets of records. A new carrier is monitored for 18 months, and FMCSA runs a safety audit once it has operated long enough to have records to review, generally at least 3 months (49 CFR 385.307). The audit covers:

  • Driver qualification: a complete file for every driver.
  • Driver duty status: hours-of-service records.
  • Vehicle maintenance: inspection, repair, and maintenance records.
  • Accident register: crashes that meet FMCSA’s definition, kept for 3 years.
  • Drug and alcohol testing: a working program, including random testing.

Some violations fail the audit on their own. 49 CFR 385.321 lists 16, including having no drug and alcohol testing program, operating without the required insurance, and knowingly using a driver without a valid CDL. If you fail, you have 60 days to fix the problems, or 45 days if you carry passengers or placarded hazmat, before your registration is revoked (49 CFR 385.319).

Our DOT safety compliance page explains what each program requires, and our audit guidance and support service prepares you and stays with you through the audit.

How our Houston team helps with DOT compliance

We work from our office at 6633 Portwest Dr, Suite 110, and support carriers across the country. Our compliance programs come in three levels:

  • Simplex Hub: a self-service approach to tracking your own compliance.
  • Essentials: on-demand support from our compliance team.
  • Managed: full-scale management with a dedicated account manager.

Across the programs, the work ranges from driver qualification file management and CSA monitoring to mock audits and hours-of-service management. We also handle trucking permits, IFTA, UCR, and commercial truck insurance, so your authority, filings, and coverage stay in step.

Use the form below to tell us about your company. Include your USDOT number, or let us know you don’t have one yet, and our team will follow up with the right program.

Frequently asked questions

Does Simplex Group have an office in Houston?

Yes. Our Houston office is at 6633 Portwest Dr, Suite 110, Houston, TX 77024. We also have offices in Miami, Rancho Cucamonga, and Richardson, near Dallas.

What do DOT compliance services include?

They keep a carrier’s FMCSA records in order: driver qualification files, drug and alcohol testing, hours of service, and vehicle maintenance and inspections. Ours also include CSA monitoring, mock audits, and support during a DOT audit.

Can a mobile inspector do my annual DOT inspection in Houston?

Federal rules let a carrier use an outside business for the annual inspection if its inspectors meet the qualifications in 49 CFR 396.19 and it has suitable facilities. Keep proof of the inspector’s qualifications. Texas also requires a state safety inspection for every commercial vehicle.

Do Texas-only trucking companies need a USDOT number?

Yes, if they need a TxDMV certificate, for example to run trucks over 26,000 pounds or haul placarded hazmat. TxDMV requires a USDOT number registered as intrastate before you apply.

Sources

The rules and figures on this page come from these official sources, checked on October 5, 2026.

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