M40 J1 Denham Roundabout

Layout and signage

N/A   A412



A4020


    A40






  Central London
A40
Slough
(A412)
Uxbridge
(A4020)

Lane configuration

LanesLanesLanesLanesLanes

  • Lane 1 exits and returns after the junction.
  • Lane 2 continues ahead.
  • Lane 3 continues ahead.

LanesLanesLanesLanesLanes

  • Lane 1 continues, with option to exit.
  • Lane 2 continues ahead.
  • Lane 3 continues ahead.

Other events

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

In this section

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London’s notorious orbital motorway turns 40 years old today. Where did it come from - and why the number “25”?

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When a road is closed, why isn't the diversion route just the quickest way past the closure?

Signs and sensibility

The one great attempt to make London’s streets logical - and how one retired chauffeur’s favourite routes changed the way you get around the capital.

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Have you seen...

Oxfordshire Signs

This is the story of one man at Oxfordshire County Council who pre-empted the development of modern road signs - much to the annoyance of the men from the Ministry.

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