Route
Junction number
4B
Markerpost
27.5 km
Name
Thorney Interchange
Type
Terminus
Not a terminus
Other routes
M25
Authority
Restricted turns
Full access
Services
No services
M4 J4B Thorney Interchange
Layout and signage
Lane configuration
- Lane 1 exits and returns after the junction.
- Lane 2 exits and returns after the junction.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
- Lane 5 continues ahead.
- Lane 1 exits and does not return.
- Lane 2 exits and returns after the junction.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
- Lane 5 continues ahead.
Other events
Variable Speed Limits apply
- Variable Speed Limits apply
What's new
The monster seen from below
What might it have been like to stand in one spot and witness the arrival, and the uncertainty, of plans for an urban motorway in West London?
The road that made no sense
It was the UK's only single-carriageway motorway, and twenty years ago it ceased to exist. This is the story of the strange fascination it held, and of my place in history.
The forever bottleneck, part 2
The second part of the story, where we learn why exactly the M4 gets narrower on the final approach to Europe’s biggest city.
Have you seen...
Thelwall Viaduct
Thousands of vehicles travel the M6 between the M56 and M62 each day. They all cross the River Mersey and the Manchester Ship Canal, and the bridge that carries them is notorious from travel reports nationwide. But what does it actually look like from the ground?
About this page
Published
Last updated
Published
Last updated
