The driveway location determines the roadway and address number. For corner lots, the National Emergency Number Association (NENA)'s standards state that if a house faces a different street than the driveway, the driveway location will be the officially recognized 911 address for emergency response. In urban areas, driveways providing access to structures that do not have their own road frontage, and which are located behind other addressable structures, should be named and addressed as streets, especially if there are 3 or more residences.