|Location Map ( geo)|
|Looking SW towards the junction|
|M1, A421, A507|
|Junctions related to the A507|
|Junctions related to the C94 (Central Bedfordshire)|
Originally a lightly trafficked diamond with the B557, M1 Junction 13, or Ridgmont Interchange has grown in importance in the years since it opened - as it became the main junction for Bedford (with the A5140 extending to the junction) and parts of Milton Keynes (which wasn't there when the junction opened) when the A421 was built. The A507 got diverted to the junction when the area to the south got renumbered, when the A418 was cut back to Leighton Buzzard. The A507 has since been upgraded to a major local route between the A1 and M1, with a recent bypass of Ridgmont changing which side of the junction it met, and the A421 has become a trunk road, serving East-West traffic across the South Midlands between Milton Keynes and Cambridge.
From 2008 to 2010 the junction was upgraded to support the dualled A421 to the north. The end result was a 'triple-diamond' with a new bridge over the M1.
|The NORTH, Milton Keynes|
|Ampthill, Ridgmont, Woburn (A4012), Husborne Crawley, Station, Marston Gate Distribution Centre|
|Brogborough, Marston Moretaine||old A421, formerly A5140, originally B557|
|Husbourne Crawley||old A507, originally B557|
- The M1 Motorway (Junction 13 and Connecting Roads) Order 2008 - This Order would establish the line of four new slip roads to be constructed at M1 Junction 13 on a different alignment to the existing slip roads, which will connect the motorway to a new roundabout on the A421 Trunk Road. The four existing slip roads will be stopped up.
- The A421 Trunk Road (M1 Junction 13 to Bedford Improvements (Salford Road) Detrunking Order 2018 - This order removes trunk road status from a small section of the unclassified Salford road that was constructed as part of the junction improvements, but isn't relevant to either A421 or M1 turning traffic at the interchange