Attorney Brian White Personal Injury Lawyers | August 4, 2025 | Auto Accidents
When it comes to driving in Texas, the difference between interstate and intrastate highways matters. These two types of roads serve different purposes and fall under different rules. Knowing the difference can affect commercial driving licenses, safety regulations, and business operations.
An interstate highway goes between states. An intrastate highway stays in one state. If you’re driving from Houston to another part of Texas, you may be using intrastate routes. If you’re headed out of state, you’re likely traveling on the interstate system.
What Is an Interstate Highway?
The Interstate Highway System is a network of controlled-access roads. It connects all 48 contiguous states. These highways were created in the 1950s to improve national defense and transportation.
In Texas, interstates like I-10, I-45, and I-35 are major routes for:
- Long-distance travel
- Trucking and freight transport
- Cross-country commuting
The federal government funds and regulates interstate highways. Commercial drivers using interstate highways are often subject to stricter rules, such as:
- Federal hours-of-service limits
- DOT medical certification
- Vehicle inspection and maintenance standards
Because they cross state lines, they must follow federal transportation laws.
What Is an Intrastate Highway?
An intrastate highway stays within Texas. These roads can still be major thoroughfares, but they don’t cross into another state.
Examples of intrastate highways in Texas include:
- TX-6, which runs from the Gulf Coast up to Waco
- TX-99 (Grand Parkway), circling the greater Houston area
- Loop highways within cities like Houston’s I-610
The Texas Department of Transportation (TxDOT) regulates these highways, not the federal government. Intrastate commercial drivers might skip federal trucking rules. However, they must still follow state requirements.
Why Does This Difference Matter?
The difference between interstate and intrastate highways is more than just geography. It can affect:
- Licensing: Some drivers require a CDL with an interstate endorsement to drive across state lines.
- Insurance: Insurance rules may differ based on whether a company operates in-state or out-of-state.
- Regulation: Federal rules govern interstate commerce, while states handle intrastate transportation.
- Liability: If an accident happens, it matters whether the travel was interstate or intrastate. This can affect legal procedures and rules.
Businesses that ship goods, drive trucks, or run buses should know the differences. This knowledge helps them stay compliant and avoid costly errors.
How Interstate vs. Intrastate Designations Affect Commerce
The difference between interstate and intrastate commerce is key for trucking companies and independent drivers. A vehicle is part of interstate commerce if it crosses state lines. It also counts if it carries goods for delivery in another state. This applies even if the truck stays in Texas.
This affects:
- Hours-of-service regulations
- Drug and alcohol testing programs
- Vehicle markings and registrations
- Record-keeping and audit rules
Drivers and companies that work only in Texas have fewer federal rules. But they still must follow state law.
Common Misconceptions About Interstate and Intrastate Highways
Some drivers believe that as long as they don’t cross a state line, they’re always intrastate. But that’s not always true. Transporting goods for an interstate shipment means you’re likely engaged in interstate commerce.
Here are a few examples:
- Driving a package from a Houston warehouse to a local post office is interstate delivery.
- Moving construction materials between Texas cities without crossing state lines is intrastate.
- Transporting passengers on a bus route to another state is interstate.
Understanding these distinctions protects you from penalties and helps ensure compliance.
Contact a Houston Personal Injury Lawyer to Help You With Your Claim
Interstate highways cross state lines and follow federal rules. Intrastate highways stay in one state and follow state guidelines. No matter if you’re a commercial driver, a logistics company, or a traveler, knowing the difference keeps you legal and informed on Texas roads.
If you have been injured in an interstate or intrastate highway car accident, a personal injury lawyer can help.
For more information, contact the Houston personal injury law firm of Attorney Brian White Personal Injury Lawyers by calling (713) 500-5000.
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