April 27, 2015- A 2015 Ford F250 propane vehicle is filled with propane at Amerigas in Commerce City, CO. (Photo by Dennis Schroeder / NREL)
April 27, 2015- A 2015 Ford F250 propane vehicle is filled with propane at Amerigas in Commerce City, CO. (Photo by Dennis Schroeder / NREL)


Propane, or liquefied petroleum gas (LPG), is the third widest used transportation fuel in the world, following gasoline and diesel. Propane is an odorless, non-toxic hydrocarbon gas at normal pressures and temperatures. When pressurized, it is a liquid with an energy density 270 times greater than its gaseous form. A propane vehicle operates similarly to a gasoline or diesel vehicle by burning the gas in an internal combustion engine. Since the fuel is cleaner-burning, a propane vehicle has fewer emissions, and propane helps reduce our dependence on foreign oil.

Propane School Buses are just better…

A very common application for propane is in school buses, where propane can be bought in bulk for much cheaper than diesel to save on operating costs, and the buses are also much quieter. The animated video below creatively explains these benefits and more.



Is propane safe for vehicle use?
Yes. Propane vehicles must meet the same safety standards as gasoline vehicles and have passed rigorous crash testing. In addition, propane has an incredibly narrow flammability range, and its tanks are 20 times more puncture-resistant than gasoline tanks. And, there is low-to-no chance of the propane escaping the tank.
What propane vehicles are available?
Two types of propane vehicles are readily available:

  1. Dedicated vehicles that run solely on propane
  2. Bifuel vehicles that have two separate fueling systems

Vehicles can either be converted to use propane or delivered as dedicated propane vehicles directly through select original equipment manufacturers’ (OEM) dealerships. Certified technicians can install U.S. Environmental Protection Agency (EPA) and/or California Air Resources Board certified propane conversion systems on a variety of vehicles. For more complete lists of certified conversion systems, click here. Medium-duty propane vehicles and heavy-duty propane engines are also available; to find them, use the Heavy-Duty Vehicle and Engine Search on the Alternative Fuels Data Center (AFDC) website.

How do propane vehicles work?
Propane vehicles operate much like gasoline vehicles with spark-ignited engines. There are 2 types of fuel-injection systems available:

  1. Vapor Injection
    • In vapor-injected systems, liquid propane is controlled by a regulator or vaporizer, which converts the liquid to a vapor. The vapor is fed to a mixer located near the intake manifold where it is metered and combined with filtered air before being drawn into the combustion chamber and burned to produce power, just like a gasoline engine.
  2. Liquid Injection
    • In liquid-injected systems, fuel is delivered into the combustion chamber, or intake port, in a liquid form (instead of a vapor). This way, the fuel combusts more fully and provides optimal power and throttle response.

In both types, propane is stored as a liquid in a relatively low-pressure tank (about 300 psi).

How do propane vehicles perform?
Propane vehicles are similar to their gasoline counterparts with regard to power, acceleration, and cruising speed. The driving range of bifuel vehicles is comparable to that of gasoline vehicles, and the fuel economy of dedicated propane vehicles is slightly lower due to propane’s lower energy content. Larger storage tanks can increase range, but the additional weight displaces payload capacity. Generally, a gallon of liquid propane has about 25% less energy than a gallon of gasoline.
How much do propane vehicles cost?
OEM delivered light-duty propane vehicles can cost several thousand dollars more than comparable gasoline vehicles. However, federal tax credits may offset the increased vehicle cost and many states have additional incentives that further incentivize the purchase of a propane vehicle. Vehicle conversions may also qualify for tax credits and other incentives. For the latest information on incentives, visit the Federal and State Incentives and Laws section of the AFDC website.

The lower maintenance costs are also a prime reason propane is popular for high-mileage vehicles. Propane’s high octane rating (104 to 112 compared with 87 to 92 for gasoline) and low-carbon and oil-contamination characteristics have resulted in the documented engine life of up to two times that of gasoline engines. For more information, click here.

Where is propane available?
Propane is widely available. There are more than 2,400 propane stations in the U.S. Please use the Propane Fueling Station Locator below to find a station near you.
Where can I learn more about propane?
To learn more about propane as a transportation fuel, visit the AFDC’s Propane section, visit the Propane Education & Research Council website, the National Propane Gas Association website, the national Clean Cities website, or just reach out to us personally! We’re happy to answer any questions you may have!

Propane Fueling Station Locator

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