Mileage Marathons

It must be accepted that the motor car is not an outstandingly efficient device for converting chemical energy into useful mechanical work. The question of why efficiencies are characteristically so low can be discussed at many levels, but at a strictly practical level it reduces to how far could a motor car go on a quantity of fuel if some or most of the constraints on its construction and use were removed. This question forms the basis of the mileage marathons which have been run at the Shell laboratories for a number of years.