disclosed is a device for providing a preliminary alert to the driver of a vehicle approaching an overhead obstacle . the inventive concept consists of a vertical mounting post to which is attached a non - marring horizontal height restrictor arm . the position of the height restrictor arm on the vertical post is at the same vertical distance from the roadway surface as is the vertical distance of the specific overhead obstacle for which an alert is provided . the height restrictor arm is affixed to the vertical post by means of a multi - directional pivotal connector comprising a hollow sphere , spring , and chain assembly . the pivotal connector allows the height restrictor arm to move , after contact by a vehicle , in a multitude of directions , fore and aft , up or down .