Over a quarter of a million propane vehicles are on the road in the U.S. with millions worldwide. Propane, also called Autogas when used for vehicles or liquefied petroleum gas (LPG), is the most used alternative vehicle fuel today. Most propane vehicles are used in fleets, converted from vehicles originally manufactured to run on gasoline. Similar to natural gas, it is abundant in North America and is commonly used in homes in rural areas for heating, indoor cooking, and barbecues. Propane is colorless and odorless. An odorant is added as a leak detection safety measure. Propane is one of the simplest hydrocarbons, making it very clean burning, even though it is a non-renewable fossil fuel produced from natural gas and oil processing. Propane emissions have 40% less particulate matter (PM-10), 50% less oxides of nitrogen (NOx), and 87% less total hydrocarbons (THC) than gasoline. With minimal emissions, propane is also widely used in indoor commercial applications, such as forklifts. One disadvantage is that propane contains less energy per volume than gasoline, so a vehicle’s driving range is reduced unless additional storage capacity is added. Propane does not have an extensive pipeline delivery infrastructure like natural gas, but it is easily transported and stored under moderate pressure in tanks. Propane has more fueling stations than any other alternative fuel.