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Green Vehicle Laws and Regulations in Texas

Texas mandates numerous vehicle laws specific to protecting the planet. These green vehicle regulations include emissions testing, alternative fuel taxes on propane, compressed and liquefied natural gas, idling restrictions, and more.

The eco-friendly driving laws below and the relevant green driver incentives are subject to change. Keep up with the latest by periodically referring back to this page and also consulting your local Department of Transportation (DOT) branch and the Alternative Fuels Data Center.

Texas Emissions Test Requirements

Texas requires all vehicles to undergo an annual inspection to maintain valid TX vehicle registration. Additionally, vehicles registered in the following 17 counties must also pass an emissions test:

  • Brazoria.
  • Collin.
  • Dallas.
  • Denton.
  • El Paso.
  • Ellis.
  • Fort Bend.
  • Galveston.
  • Harris.
  • Johnson.
  • Kaufman.
  • Montgomery.
  • Parker.
  • Rockwall.
  • Tarrant.
  • Travis.
  • Williamson.

There are exceptions. If you drive an electric vehicle (EV) or any other car not capable of operating on gasoline, or a diesel-powered or new (less than 2 model years old) vehicle, Texas offers an emissions test exemption. This does not include hybrids. Check out the DPS Vehicle Inspection Program and our page on TX emissions testing for full details. Also, you can find smog and emissions testing stations in your area using our Emissions Testing Station widget below.

Emissions test exemptions are just one perk of driving an eco-friendly car. For more, refer to our page on green driver incentives.

TX Alternative Fuel Taxes

Certain alternative fuels come with different fuel taxes than gasoline or diesel. The following subsections have more details.

Liquefied Gas/Propane Tax Decal

If your vehicle runs on liquefied gas (propane), you must annually obtain a decal designating your advance payment of a fuel tax based on your vehicle's registered gross weight and mileage (driven the year prior). This tax specifically applies to liquefied gas purchased to power a motor vehicle on Texas public highways. You'll purchase this decal from the Texas Comptroller of Public Accounts.

For first-timers, Texas bases the tax rate on an estimated amount of miles you will drive your propane-powered vehicle in the year following the decal's date of issuance. Refer to Texas Statutes, Tax Code (Section 162.305) for full details, including a table of taxes calculated by vehicle weight and mileage.

Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG) Tax

Texas imposes a $.15 per gasoline gallon equivalent (GGE) or diesel gallon equivalent (DGE) on compressed natural gas (CNG) and liquefied natural gas (LNG) used to power motor vehicles.

As a consumer, you'll pay the tax to the dealer who will have already factored the tax into the selling price. For more info, consult Texas Statutes, Tax Code (Section 162.353).

Compressed Natural Gas (CNG) Container Inspection Requirements

If you own a vehicle that runs on compressed natural gas (CNG), you must be able to prove the following in order for your vehicle to pass TX vehicle inspection. Your NGV's gas container must:

Additionally, fleet vehicles must undergo a container inspection by a certified technician (hired by the fleet operator).

For specifics, consult the Texas Statutes (Transportation Code 548.104).

Texas Vehicle Idling Restrictions

Texas prohibits drivers from causing or allowing the primary propulsion engine of a motor vehicle to idle more than 5 minutes if the vehicle is not in motion. Some exceptions to the rule include vehicles that:

  • Have a gross vehicle weight rating that exceed 14,000 lbs. and one of the following types of engines (model-year 2008 or newer) certified by the Environmental Protection Agency (EPA) or another TX environmental agency to emit 30 grams or fewer of nitrogen oxides emissions per hour of idling:
    • Heavy-duty diesel engine.
    • Liquefied natural gas engine.
    • Compressed natural gas engine.
  • Are forced to remain motionless by traffic.
  • Utilize the primary propulsion engine as a necessary power source for mechanical operation (other than propulsion) and/or heating and cooling the passenger compartment.
  • Require the power of the primary propulsion engine to defrost a windshield.

Additionally, if your vehicle meets the following criteria, the TCEQ may not limit or prohibit idling:

  • Has a gross vehicle weight rating that exceeds 8,500 lbs.
  • Has a model-year 2008 (or newer) heavy-duty diesel, liquefied natural gas, or compressed natural gas engine that is certified by the EPA or another TX environmental agency to emit 30 grams or less of nitrogen oxides emissions per hour of idling.

For the purposes of this law, idling refers to allowing an engine to run while the vehicle is not moving forward or backward. The Texas Statutes, Health and Safety Code (Section 382.0191) specifically covers these exceptions.

Neighborhood Electric Vehicle (NEV) Driving Restrictions

Driving a neighborhood electric vehicle in Texas comes with a couple of restrictions:

  • You may not operate neighborhood electric vehicles on local streets or highways with a posted speed limit greater than 45 MPH (miles per hour (mph). However, an NEV may cross an intersection of a road or street that has a posted speed limit greater than that maximum.
  • You may not operate an NEV on a street or highway at a speed that exceeds the lesser of the posted speed limit or 35 MPH.

Keep in mind, TX counties, municipalities, and the Department of Transportation may prohibit the operation of neighborhood electric vehicles altogether in the interest of public safety.

For the purposes of the above regulations, Texas defines a neighborhood electric vehicle as one that is:

For more info on NEV driving restrictions, consult your local branch or the Texas Statutes, Transportation Code 551.301-551.303.

San Antonio Hybrid Vehicle Parking Program

San Antonio's Downtown Operations Parking Division has established a Hybrid Vehicle Parking Program for San Antonio residents. Per this program, drivers of hybrid vehicles can park at any of the parking meters and other parking locations for free.

For more information, visit the Hybrid Vehicle Parking Program website or call the Division at (210) 207-8266.

Find a Nearby Texas Emissions Testing Station

Locate the closest TX smog and emissions testing station with the widget below:

Please enter your ZIP code OR city and state abbreviation


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