A service road, or frontage road, parallels a freeway and provides access to the highway at each interchange. Businesses, such as gas stations, restaurants, and motels, may be located along the service road. On occasion, a service road in rural areas may actually be the original alignment of the highway prior to the construction of the freeway. A service road might be called into service as the main route whenever the main lanes of the freeway are closed for any reason. Texas maintains a far reaching system of service roads along the majority of the freeway system.