A5183 ROAD

The 'A5183 road' is the A5 road in disguise. It covers the road from Junction 9 of the M1 motorway to Edgware in London, largely along Watling Street. The renumbering was to prevent drivers of heavy southbound vehicles assuming that a low number '5' indicated a superior quality road which this stretch is not as it is narrow in many places.
Possibly the main beneficiary of this renumbering is the city of St Albans that used to be 'host' to both the A5 and the A6. A similar subterfuge has been made with that part of the A6, which is now renumbered to the A1081 road.