Gasoline was rationed in 17 eastern states beginning in May 1942 and nationwide in December 1942 -- not so much to save fuel as to save tires and the rubber they were made of. A nationwide speed limit of 35 miles per hour was also enforced to save wear on tires. To ration gasoline, the government issued coupon stamps. These "A" stamps were worth three to five gallons of gasoline per week for essential activities such as shopping, attending church, and going to the doctor. The letter on the stamp would have matched a sticker on the car's windshield. People using their cars for work could buy more gasoline, and truckers could buy all they needed.
Public Domain is a copyright term that is often used when talking about copyright for creative works. Under U.S. copyright raw, individual items that are in the public domain are items that are no longer protected by copyright law. This means that you do not need to request permission to re-use, re-publish or even change a copy of the item. Items enter the public domain under U.S. copyright law for a number of reasons: the original copyright may have expired; the item was created by the U.S. Federal Government or other governmental entity that views the things it creates as in the public domain; the work was never protected by copyright for some other reason related to how it was produced (for example, it was a speech that wasn't written down or recorded); or the work doesn't have enough originality to make it eligible for copyright protection.