Natural gas vehicles numbered 13.9 million vehicles globally in 2010, up substantially from 2.8 million in 2003. Since 2000 the global growth rate for NGVs has been 26 per cent per year. About 1 per cent of all vehicles on planet earth now run on natural gas and most of them are light duty or cars.
In the USA just 120,000 natural gas vehicles are operating on gas or about 1 out of every 10,000. Here most vehicles running on natural gas are heavy duty vehicles or trucks and buses. As a result, about 0.2% of the fuel used in America for transportation is gas. In 2010 45 billion cubic feet of natural gas was used to power vehicles on our roads.
While the USA has a slow growth rate in natural gas vehicles, the growth rate in gas for transportation has been 25%, as niche markets like transit buses, refuse trucks, and taxi fleets show major growth. The vehicles in the USA that are running on gas are big and use a lot of fuel-- typically the equivalent of 5,000 to 15,000 gallons per year.
Notable successes include the Los Angeles transit system recently retiring its last diesel bus. The California Air Resources Board calculates that a natural gas vehicle emits 22% to 29% less carbon than vehicles running on diesel and gasoline respectively.
Just two ways exist for cutting the major carbon emissions from transportation: fuel efficiency and switching to lower carbon fuels than gasoline and diesel.