rule of the road
noun pl. rules of the road
- A set of customary practices, especially for the operation of a motor vehicle, boat, or aircraft, established to promote efficiency and safety. Often used in the plural.
- A set of established rules or practices, usually unstated, intended to minimize confusion or conflict. Often used in the plural: “Great powers … wishing to avoid war could resort to one of three tools: condominium, spheres of influence or rules of the road” (Charles William Maynes).