Natural gas vehicles are either fueled exclusively with CNG or LNG (dedicated NGVs) or are capable of natural gas and gasoline fueling (bi-fuel NGVs). Natural gas can be used in the form of compressed natural gas (CNG) or liquefied natural gas (LNG) to fuel cars and trucks.

Dedicated natural gas vehicles (NGVs) are designed to run only on natural gas; bi-fuel NGVs have two separate fueling systems that enable the vehicle to use either natural gas or a conventional fuel (gasoline or diesel). In general, dedicated NGVs demonstrate better performance and have lower emissions than bi-fuel vehicles because their engines are optimized to run on natural gas. In addition, the vehicle does not have to carry two types of fuel, thereby increasing cargo capacity and reducing weight.

Compared with vehicles fueled with conventional diesel and gasoline, Natural gas vehicles burn less CO2, less NOX and less particulates.

The driving range of NGVs generally is less than that of comparable gasoline and diesel fueled vehicles because of the lower energy content of natural gas.