Diesel Vehicles

Improvements in diesel engine technology allow modern automotive diesels to be quiet, powerful and clean enough to meet California's emission standards.


Generally, diesel vehicles offer better fuel economy, longer range and more torque than gasoline vehicles. Diesel engines are very durable with lower maintenance needed, and with no spark plugs, diesels never need ignition tune-ups. Still, gasoline and diesel vehicles in California account for a significant portion of emissions in the transportation sector, making zero-emission cars such as battery-electric, plug-in hybrid and fuel cell electric cars an attractive alternative to diesel models.

How They Work

The primary difference between gasoline and diesel engines is how the fuel is ignited. Gas engines use a spark in the cylinder to ignite the fuel, and diesel engines compress the air within the cylinder to produce ignition.


Several manufacturers have introduced diesel passenger cars in California with more coming in the future. Diesel emissions can vary widely, so be sure to compare the greenhouse gas and smog ratings on the on the Fuel Economy and Environment Label before you buy. Search vehicles to see available models.


Diesel engines provide more power and fuel efficiency than those powered by gasoline, compressed natural gas or liquefied natural gas.


Diesels can be costly compared to similarly powerful gasoline engines because of the extra technology that goes into making diesels perform well on the road and comply with emissions standards.

While the average price of diesel fuel has been lower than the average price of gasoline in the past, today it is about the same. Worldwide demand for diesel fuel and other distillate fuel oils has been steadily increasing, with strong demand in China, Europe and the United States, putting more pressure on the tight global refining capacity.


Diesel vehicles do not typically qualify for incentives.


Many gas stations offer diesel fuel. The U.S. Department of Energy Alternative Fuels Data Center is a good reference for fueling locations.

Diesel Scandals

In some cases, the anticipated emissions benefits from diesel engines have yet to be realized because some automakers had voided the required emissions control technologies. These automakers are dealing with legal actions against them, resulting in billions of dollars in court judgements, and civil and criminal penalties.

Additional Resources

Diesel Technology Forum