A running board is a narrow step fitted under the side doors of a car or truck. It aids entry, especially into high vehicles, and is typical of vintage cars, which had much higher ground clearances than today's vehicles. It is also used as a fashion statement on vehicles that would not otherwise require it. The origin of the name running board is obscure; the first running boards predate automobiles and were installed on carriages as early as the 17th century. Whether the running board was named after the inventor or in reference to function is open to debate.
Running boards may also be used to stand on while the vehicle is moving. The name running board is also given to safety appliances for walking on rail cars.
The term also applied to the walkways on top of railroad boxcars. Originally, they were used by brakemen to travel from car to car to apply hand-operated brakes. With the adoption of the air brake this practice was abandoned. However the running board was still used as an observation point to pass hand signals to the train engineer when cars were being switched. The increased use of radio communication made this unnecessary. Today it is forbidden for anyone to be on top of a freight car while the train is in motion.