Abstract: A device for providing a preliminary alert to the driver of a vehicle of an approaching overhead obstacle of a given height. A horizontal clearance bar is pivotally attached to a vertical support post which allows the clearance bar to move, after contact by a vehicle, to alert the vehicle driver to an upcoming obstruction without damaging the vehicle. The clearance bar is mounted at a slight angle with respect to the support bar, allowing it to use the force of gravity in returning from an extended position to an initial rest position. The vertical support has mounting holes on either of two opposing sides in a particular pattern which allows one clearance bar to be mounted on either side, or a pair of clearance bars to be mounted on opposite sides of the vertical support by merely flipping the position of one of the clearance bars relative to the other.