That window ration sticker Wayne is talking about. Was issued during World War II. The "A" ration sticker only allowed for 4 gallons of gas per week. Rationing started in early 1942. The "A" ration was the most common sticker issued to the general public. The "B" stickers were given to business owners and allowed 8 gallons per week. The "C" sticker was issued primarily to professional people: physicians, nurses, dentists, ministers, priests, mail delivery people, embalmers, farm workers, construction or maintenance workers, soldiers and armed forces going to duty. The "M" sticker was issued to motorcycle drivers. This included the Western Union company and other types of delivery people who used motorcycles for their business. The "T" sticker was issued to truck drivers. The "X" sticker was issued in special cases that involved high mileage type jobs. Traveling salesmen could get these. They were also held by the rich and politicians.
Gasoline rationing wasn't really to conserve gasoline. The United States had a lot of oil resources. It was to control the consumption of tires. Rubber imports were drastically affected by the war in the Pacific theater.