Toward the latter part of the 19th century, a series of laws required motorists, both in the United Kingdom and the United States, to have a person walking in front of their vehicle carrying a red flag to warn other road users of the potential danger. Needless to say, the need for a pedestrian waving a red flag ahead of the driver spoiled one of the most obvious value propositions of the new technology, which was the ability to move quickly.
