The A3393 is a rather curious find in the 1975 AA Touring Guide. It shows the Salisbury ring road complete, with the northern section marked as A3393. The only other road numbers indicated are on the edges of the town plan, so routes through the city cannot be identified. However, as there are no classified inbound junctions between Castle Street and Exeter Street, it must be assumed that the A30 (not to mention the A36) multiplexes with the A3393 for the entire route of the latter.
The number also appears in the DfT road lists, saying that the number was created on 20.4.69.
The A3393 number presumably comes from the B3393, which ran along St Paul's Road and Wyndham Road before the ring road was built. The route is now entirely part of the A36.
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