LPG / CNG / LNG / L-CNG is called Autogas when used as a motor fuel. With  million vehicles worldwide running on Autogas.

 Those are the most widely used alternative fuel in the world, just behind gasoline and diesel.

 LPG / CNG / LNG / L-CNG are the generic names used for mixtures of hydrocarbons. When these mixtures are lightly compressed they change from a gaseous state to a liquid.