A470 Upper Boat Interchange

Layout and signage

Rhydfelen
Rhydyfelin
A4054
  A4054
A473
A4054
      Yst Ddiw Trefforest
Treforest Ind Est
A4054

Lane configuration

LanesLanesLanesLanes

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

LanesLanesLanesLanes

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

In this section

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.

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Road Numbers

We'd be lost without them, but there is nothing straightforward about the seemingly simple business of giving roads a number.

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