Liquefied Petroleum Gas, which is simply gas turned into liquid form so it can
be stored more densely when used as an engine fuel.
Some car-makers now have LPG vehicles in their range which are designed to run
best on LPG only.
While LPG is cheaper than petrol, LPG cars tend to use about 30 per cent more
fuel than their petrol-only equivalents, which must be considered when weighing
up the cost benefits.