The Adur Viaduct (also known locally as the Shoreham Flyover) spans the Adur valley and River Adur, combining with the junction of the A27 and A283. It was built as part of the Shoreham-by-Sea Bypass, construction starting on 1 February 1968 and being completed in 1970. It was opened westbound on 14 May 1970 and eastbound on 21 May 1970, although the slip roads did not open until July 1970. The cost of the whole Shoreham Bypass, including the viaduct, was estimated to be £2,707,294.
An early box girder bridge that has needed repeated strengthening since construction. Reinforced concrete pillars support the viaduct and the upper ends of the slip roads, with the lower ends being on embankments. Recently resurfaced with anti-skid surfacing used on the tight corners. The Adur Valley rail line used to run under the viaduct as well.