Sharing rides to save tires
THis U.S. Government poster from World War II advises Americans to conserve fuel. Poster shows a man driving a car with a shadowy Hitler in the passenger seat, with caption "When you ride alone you ride with Hitler! Join a car-sharing club today!"
To save tires, the government asked Americans to cut back on their driving, to save gas by driving more slowly, and to share rides. (The term "carpooling" didn't exist yet.) These efforts continued throughout the war, as you can see in this 1943 poster. But Americans have never been eager to drive less or more slowly, and by the spring of 1942 it was clear that "voluntary rationing" was a failure.
Public Domain
Public Domain is a copyright term that is often used when talking about copyright for creative works. Under U.S. copyright law, 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.