Q: I have a 1916 auto dealer’s license plate from Pennsylvania. I’d like to know the history of license plates.

A: In 1901 New York became the first state to require license plates, but the owner of the vehicle had to make his own plates. Massachusetts was the first state to make license plates, beginning in 1903. Pennsylvania began issuing license plates in 1906. Early plates were enamel and were issued to the driver, not the vehicle. The first plates issued for a specific vehicle were made in 1910. A metal tag in the shape of a keystone was attached to each plate. The first plates for dealers were also made in 1910, but without the keystone. The letter “X” was added to dealer plates in 1911. Metal plates were introduced in 1916. Collectors search for plates with low numbers or special number combinations, plates made of unusual materials, those that are smaller than usual or commemorate special events, plates that have unusual pictures or slogans, interesting vanity plates, and special plates that belonged to a famous person or were used in a movie or TV show. The plate “OUTATIME,” used on the DeLorean in the 1985 movie “Back to the Future,” sold for $10,620 in 2010. Ordinary license plates often sell for less than $5. There is a club for collectors of license plates, Automobile License Plate Collectors Association, Inc., 118 Quaker Rd., Hampton, VA 23669-2024, website www.alpca.org.