The expressway is an important route connecting the greater Tokyo area with
Mito, the capital of
Ibaraki Prefecture. Beyond Mito, the expressway follows a northerly route along the coast of the Pacific Ocean to the city of
Iwaki in
Fukushima Prefecture. Continuing north along the coast, the expressway enters the greater
Sendai area. The expressway supplements the
Tōhoku Expressway as an access route between Tokyo and the
Tōhoku region. For most of its length the expressway parallels
National Route 6 and the
Jōban Line of
East Japan Railway Company. The expressway gets within about six kilometers from the damaged
Fukushima Daiichi Nuclear Power Plant. On a of the expressway opened on 1 March 2015, signs update drivers about what the radiation level is in the impacted area.
Naming Jōban is a
kanji acronym consisting of two characters. Each character represents a former province of Japan that is passed through by the route: representing present-day
Ibaraki Prefecture and representing the eastern portion of present-day
Fukushima Prefecture The expressway carries the Jōban Expressway name from the origin at Misato Junction to
Watari Interchange. From Watari Interchange to the expected terminus at Tomiya-kita Interchange, the Jōban Expressway name is currently an official designation only. The section from Watari Interchange to
Sendaikō-kita Interchange is the
Sendai-Tōbu Road, the section from Sendaikō-kita Interchange to
Rifu Junction is the
Sanriku Expressway (Senen Road), and the section from Rifu Junction to the terminus is the
Sendai-Hokubu Road. It is unknown if the naming of these sections will be changed upon completion of the Jōban Expressway. The expressway has a speed limit of 70 km/h between Iwaki-chūō Interchange and its northern terminus at Watari, a limit of 80 km/h between its southern terminus and Kashiwa Interchange and between Hitachiminami-Ōta and Iwaki-chūō interchanges, and a speed limit of 100 km/h on the remainder of the expressway. ==History==