They have Gasoline Shortage in London, Too - A workman attaches a producer gas unit to the rear of a truck in London garage so that the vehicle will not be dependent on gasoline for its fuel supply. This apparatus uses a non-petroleum substance to generate producer gas on which truck engine will operate the change over is being made in order to comply with an expected ministry of transport request that trucks be converted to conserve Britain's Petroleum supply. May 18, 1942. (Photo by AP Wirephoto).