CLEVER (Compact Low Emission Vehicle for Urban Transport) vehicle

…Running on compressed natural gas, the vehicle would not only help preserve stocks of oil but would emit about a third of the carbon dioxide than conventional family cars. Because it does not run on petrol or diesel, it would not be liable for the congestion charge in London, or any other city where the charge is likely to be adopted. Its fuel consumption is equivalent to 108 miles per gallon (or 2.6 litres per 100 kms) with petrol, a third of most cars.

University of Bath