A1(M) J1 South Mimms Interchange

Layout and signage

Stansted Airport (M11 Link)
Dartford Tunnel (M20 Link)
Heathrow Airport (M4 Link)
M25 Link
Barnet A1081
Services South Mimms
  M25
(M4)
   

M25
(M11)
(M20)

A1081
  Stansted Airport (M11 Link)
Dartford Tunnel (M20 Link)
Heathrow Airport (M4 Link)
M25 Link
Barnet A1081
Services South Mimms

Lane configuration

LanesLanesLanesLanesLanes

  • Lane 1 exits and does not return.
  • Lane 2 continues ahead.
  • Lane 3 continues ahead.

LanesLanesLanesLanesLanes

  • Lane 1 is gained from the entry sliproad.
  • Lane 2 continues, with option to exit.
  • Lane 3 continues ahead.

Other events

  • Signs Start of motorway regulations
  • Signs End of motorway regulations

In this section

What's new

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.

The forever bottleneck, part 1

The M4 into London was one of the UK's earliest and most ambitious motorway projects. It was bold, pioneering... and almost instantly regretted.

Hello, here's my ridiculous side project

An introduction to what I write, and why I write it, and where my strange new road sign simulator fits in to all this.

Share this page

Have you seen...

Daniel "Swampy" Hooper

Britain's most famous anti-road protester, who shot to fame in the mid-1990s and came to represent the whole environmental movement.

About this page

Published

Last updated