M6 - M58 (original) (raw)
Where is it?
M6 junction 26, just west of Wigan. The junction allows movement between north-south traffic on the M6, traffic to and from Liverpool on the M58 and Wigan on the A577.
What's wrong with it?
The main problem is that it's so underpowered to say this is the terminus of a motorway, and a radial motorway from a major city at that. A large amount of traffic is heading north from Liverpool (or vice versa) and these movements take long cumbersome routes, going round roundabouts and 180-degree loops. In addition, the nature of the roundabouts means the three-lane M58 has to drop to two lanes shortly before the roundabout. Finally, there is a single carriageway (but still motorway class) spur road to the A577 which leaves the eastern roundabout — as a motorway it should be a dual carriageway!
Why is it wrong?
This wasn't meant to be the terminus of the M58. The 'flared' carriageways show it was meant to continue east, the original plan taking it round the south of Wigan to meet the M61. It is hard to see how this interchange would have allowed this — presumably the M58 would have gone over the top on a third level and had east-facing sliproads to the eastern roundabout. Had this happened, the junction wouldn't have been so bad and additional junctions for Wigan from the M58 would have been provided further east. Presumably the link to the A577 was a temporary measure to ensure Wigan to Liverpool traffic could use the M58 until this happened. The odd looped sliproads are obviously forced by the built-up land to the north.
What would be better?
If the link to the A577 wasn't there it would be quite simple to convert this to a (small) trumpet interchange — a small east-to-north sliproad could be added north of the M58, the roundabouts removed entirely and the eastern one replaced with straight-through links to form the loop. Luckily traffic levels here aren't so high that any 'fix' is really required.