Hitsuishijima Viaduct, Road-rail viaduct in Sakaide, Japan

The Hitsuishijima Viaduct is a double-deck bridge in Sakaide that carries trains on one level and cars on another. The structure uses a rigid frame design to span across the water while supporting both forms of traffic at the same time.

Work on the viaduct began in 1978 and was completed in 1988, as part of the Seto Ohashi bridge project linking Honshu and Shikoku. It stands on Hitsuishijima in Sakaide, Kagawa Prefecture, between the Shimo-Tsui Seto Bridge and the Hitsuishijima Bridge.

The viaduct forms part of the Seto Ohashi route, with the Seto Central Expressway on its upper deck and the Honshi-Bisan Line (Seto Ohashi Line) below. Its neighbours along the route are the Shimo-Tsui Seto Bridge and the Hitsuishijima Bridge.

The bridge features steep slopes on both sides to allow large ships to pass beneath it. Visitors should expect these slopes to be noticeable when crossing in a car or bus.

The viaduct is 1,316 m long and forms part of the Seto Ohashi bridge network, linking the Kojima-Seto Ohashi Bridge with the Hitsuishijima Bridge. Construction ran from 1978 to 1988, and the deck carries the Seto-Chuo Expressway above and the Honshi-Bisan Line below.