Almondsbury Interchange

An overhead shot of the interchange under construction

A picture of the interchange under construction from the lowest level

This article is about the interchange that is junction 20 of the M4 and junction 15 of the M5.
For junction 16 of the M5, see Almondsbury Roundabout.

The Almondsbury Interchange is the main junction for traffic to interchange between the M4 and M5. For the M4, it is Junction 20, and for the M5 it is Junction 15. The interchange is interlinked with M5 junction 16, which provides access to the A38.

The junction was the first example of a four-level stack in the country. Both motorways are dual two-lane plus hard shoulder through the interchange, though the approach roads are generally three lanes. The westbound M4 widens to 4 lanes on approach to the interchange. Link roads connecting from M4 to M5 pass over the top level of the interchange and links from the M5 to the M4 pass underneath all other levels.

The interchange opened in stages, with the M4 and M5 south to Junction 16 opening with the Severn Bridge in September 1966 and the M5 northwards in December 1971.

Construction of the Second Severn Crossing and the M49 has taken the majority of M4 traffic from South Wales to the M5 South away from the Almondsbury Interchange.

Routes

Route	To	Notes
M4	Bristol, London
M4	SOUTH WALES, Cardiff, Chepstow (M48)
M5	The MIDLANDS, Gloucester
M5	The SOUTH WEST, Weston-s-Mare, Exeter

Maps

Before the coming of the junction, 1954

First stage of opening, 1966

The M5 through the junction under construction, 1967

• 

  The current layout of the interchange.

Links

Roads.org.uk

• Opening Booklet  10.06.2020 (archive.org)
• Bad Juctions page