An improved runway lighting system comprises a first set of runway lights providing illumination in one direction along the runway, a second set of runway lights providing illumination in the opposite direction along the runway and a switching unit for switching on either the first set of lights or the second set of lights, depending on the direction of approach of incoming aircraft. A control unit provides current pulses along existing runway circuitry to operate the switching unit. Circuitry in the switching unit determines which set of lights to illuminate based upon the amplitude and duration of the current pulse. A selector switch may also be provided in the control tower to remotely operate the control unit.