M6-M61-M65 "Prospect Hill Interchange"

[wrinkly]

No, the 1960s bridge is still in use. Not all the width over it is used.

[Bryn666]

Indeed, also the parapets still point towards the old alignment.

There is a lot of tipped soil between the M6 and M61 carriageways today. A clear sign of how extensive the earthworks had to be!

[Patrick Harper]

Presumably the old slip road had to fit through here.

I always find it a bit of a shame how they had to widen the M6 to D4M rather than finish the Preston Motorway Box; look how many original relic bridges that had to be demolished to make way! There is now only one overhead left.

[Truvelo]

This thread has provided me with enough evidence to have a go at drawing a map showing the proposed layout. Paspie's post clearly shows the M6 southbound entry slip merging beneath the northbound M61 to avoid weaving. What isn't clear is what movements were provided at the limited access M6/M65 junction.

[Patrick Harper]

I've edited my above post and fixed the links to show what I meant to. Previously they didn't work properly for some reason.

[Patrick Harper]

For the M6N to M61N sliproad, the alignment seems to have remained intact up to about here where the original 1960 surface ceases. On the mainline M6 the pre-1995 lighting ends about here as well.

[SarahJ]

So is this the stub here?

http://maps.google.co.uk/maps/ms?msid=2 ... 4,0.002411


IIRC there was a relining of lanes not long after a bad crash where a HGV slammed into the back of standing traffic. It might have even been a tanker and a bus was in the standing traffic. It was a heck of a drop from 3 to 1 and late at night felt quite sudden.

SJ

[Bryn666]

That is the second stub, yes.

The HGV accident was around 1987, shortly after J9 was built. I have seen a photo of the aftermath online (the site in question has gone now), and it looked horrendous.

I don't think there was a lane drop at J9 until the M65 came along? The 3 into 1 lasted well into the 90s (the photo in the OP is from about 1992).

[Truvelo]

Based on the evidence presented in this thread I have produced this map showing the probable junction layouts.

Starting with J30 - the various stubs that (did) exist means I am satisfied that the slips I've shown around the M61 merge are accurate.

The M6/M65 junction is described as a four level partial freeflow interchange. Given the available space and the close proximity to the M61 merge I have assumed Bryn's suggestion of a roundabout is the most likely design. I'm going to take liberties with the four level comments and take the local road (Cottage Lane) to be the fourth level. I've threaded it around the junction although I'm not familiar with the gradients in the area. Closing Cottage Lane would create a lengthy detour for local traffic.

Moving westwards and we come to the A6 London Way which was built but the engineers drawing shows it running on a slightly more easterly alignment north of the M65 junction. South of the M65 I've shown it on its current course with the B5257 junction removed due to weaving issues.

The M65, which I assume is the number it would have taken, continues southwestwards as per Chris' suggestion.

[Bryn666]

That looks very realistic and what could have been built had the 'red route' been chosen in 1975.

[M4 Cardiff]

If the M65 was to originally tie in at J30 how would it have gone through or round Blackburn?

[wrinkly]

If the M65 was to originally tie in at J30 how would it have gone through or round Blackburn?

Bryn's Wiki page

[SC2]

How big a problem would weaving have been between the two roundabouts, had it been built as in Truvelo's drawing?

[Chris5156]

Based on the evidence presented in this thread I have produced this map showing the probable junction layouts.

Starting with J30 - the various stubs that (did) exist means I am satisfied that the slips I've shown around the M61 merge are accurate.

I'm not fully convinced that the braided junction you've drawn is realistic in that space. Do we know for sure that the M6 to the south would have had access to the M65 roundabout?

[Truvelo]

I'm not fully convinced that the braided junction you've drawn is realistic in that space. Do we know for sure that the M6 to the south would have had access to the M65 roundabout?

The tightest slip road is the original M61 to M6 north prior to the widening of the 1990's. All the ones I've added are much smoother so there definitely is the space for the layout I've drawn. An additional clue is Wrinkly's post at the top of this page which shows space for an M6 southbound merge beneath the bridge. Why else would the bridge be skewed with so much verge space? It can't be for increased visibility as it's on the outside of a curve.

Would the M61 stubs be built as a speculative measure or would the exact alignment of the M61 to M65 connection be known? If the latter is true then I'm sure an actual junction layout is sitting in an archives somewhere just waiting to be discovered.

[Bryn666]

The M65 route plans I worked from are all there is. As the routes were up for consultation, only the green route was refined after 1975.

There is no junction plan I am afraid.

[Haydn1971]

I'm not fully convinced that the braided junction you've drawn is realistic in that space.

Under today's geometric standards, I'd agree, but unusually for a Truvelo highway design (that's my future lifts buggered), I do actually think it would have been possible under older design standards, but perhaps under a departure from standard.

[Bryn666]

http://farm4.staticflickr.com/3661/5738 ... 583f_o.jpg

1956 Preston Bypass document, showing two-level interchange for "Belmont Link" at exact location of today's M61 merge. One for Steven!

[Norfolktolancashire]

That is the second stub, yes.

The HGV accident was around 1987, shortly after J9 was built. I have seen a photo of the aftermath online (the site in question has gone now), and it looked horrendous.

I don't think there was a lane drop at J9 until the M65 came along? The 3 into 1 lasted well into the 90s (the photo in the OP is from about 1992).

From memory it involved a fuel tanker in the collision which set off a river of burning fuel into other vehicles with horrible consequences

The lane drop on the M65 was only put in after the M65 was built, previously as noted above all three lanes merged near the M6

[Patrick Harper]

The original parapet can also be seen here, where it dips down into a mound of earth which obviously used to be the original sliproad alignment.