Abstract: A monitoring system for a car (10) having a top (12) movable along a path of movement is disclosed as including a number of pairs of infrared (IR) transmitters (22a, 22b) and infrared (IR) receivers (24a, 24b), in which each IR receiver is adapted to receive IR signals transmitted by a respective IR transmitter, and output means (52), in which the IR transmitters and IR receivers are positioned on each side of the path of movement of the top, and, in operation, the output means is adapted to produce an audio and/or visual output if at least one of the IR receivers receives no IR signals from the respective IR transmitter.