A pedal was a type of lever found on some vehicles. It could be used either to power the vehicle or trigger a specific function, such as braking.
A pair of pedals above the exercise table in USS Enterprise's sickbay allowed one to work up exertion during the medical test. (TOS: "The Corbomite Maneuver", "Charlie X", "Turnabout Intruder")
In 2268, Spock suggested that the clutch of an automobile James T. Kirk was attempting to drive on Sigma Iotia II was one of the pedals on the car's floor. (TOS: "A Piece of the Action")
In 2269, one of the Kzinti examining the Slaver weapon suggested that one of its settings was a personal rocket motor, and that it was ridden by putting one's feet on the pedals extending out from it. (TAS: "The Slaver Weapon")
In 2374, Tom Paris jokingly suggested that in lieu of deuterium, USS Voyager could set up a bicycle in the mess hall, attach a generator to it and pedal home. Kathryn Janeway asked him why she didn't think of that solution. Paris continued the joke by volunteering Harry Kim for the first shift. (VOY: "Demon")