Abstract: A breakaway coupling for use with a ground-installed road sign such as a stop sign typically located at the side of a road. The coupling interfaces between a conventional hollow ground stake and a hollow sign post. The coupling can be used with newly installed stop signs, as well as with currently installed stop signs, without modification to either the post of the ground stake. When the sign post is struck by an automobile, the coupling shears along a preformed score section generally aligned with the bottom of the post such that the post and sign break completely from the ground stake and are propelled away from the automobile.