M5 Junction 29 Works

[jamieuka]

I pass through the junction on my daily commute. Not much to report, though.

[DavidBrown]

jamieuka - Would you know what exactly have they done to the southbound off slip that justified a week long closure?

[Keiji]

I saw it (the southbound offslip) while driving southbound on the Saturday immediately before half term, it looked like it was being widened since there were a lot of earthworks going on. Although, that's what you'd expect from the plans...

[jamieuka]

Looks like as of this week everything is fully open!

[SteveA30]

The bad news I've been dreading. I just hope the eastbound lights are all synchronised. Remember, this is the one that westbound, intercepts an on-slip with signals, just before you reach the sanctuary of the M5.

[DavidBrown]

If the congestion caused by the roadworks are anything to go by, westbound will be OK, but going from M5N to A30E will be a nightmare - traffic backs up onto the main M5 and back beyond J30 every rush hour.

[Keiji]

Hopefully if they've got two lanes open and decently timed signals it should reduce the queues. I'll have to take a look myself sometime soon.

The signal timings while the roadworks were going on were appalling - they gave a lot of green time to closed movements!

[M5Lenzar]

If the congestion caused by the roadworks are anything to go by, westbound will be OK, but going from M5N to A30E will be a nightmare - traffic backs up onto the main M5 and back beyond J30 every rush hour.

Why exactly was this development allowed? I have said before that J29 was an embarrasing layout before. More lights and other associated works will just push even more SW-SE traffic up to the M4/M5, jamming Almondsbury for longer.

[DavidBrown]

I can see why the development was allowed - it's a huge boost for Exeter and brings jobs, houses and investment at a time when such things are scarce, to say the least. It's also in an area that, whilst greenfield, isn't Devon's most picturesque area and won't be missed too sorely - again something that's scarce in the area.

Personally, I would have had J29 as a junction for the A30 only, potentially turning it into a trumpet. Access to the new development and the current A3015 would be from a new J29A just to the north of the new Redhayes bridge, linking in to the Monkerton Link road and the old A30 the other end of the new Science Park. Oh, and to stop more weaving on the M5, put it all on some collector/distributor roads. This would mean that the railway bridge just north of there could be rebuilt to allow the double track railway to return. Whilst it's a lot of work and would cost a lot of money, you only have to look at the vast scale of the developments to the east of Exeter to see that even after all that, it's still a comparatively small cost.

[Gav]

The plans I see seem to be focused with the M5....

If we thought out the box and provided a new dual carriageway from the airport junction on the A30 heading south west towards junction 30 - provide an overpass and merge it into the A379 and then extend this road on a southwest route until it meets with the A30 again. If you look into the traffic flows you could reduce the confict on the M5 and leave this as a main north south route and allow the A30 traffic to remain on a purpose built route - an alterative route so to speak. Add in some slips to the new A30 from the M5 and you can then remove the off slips from Junction 29 proper

Reasses the flows on the junction 29 do we really need an access to the M5 if this alternative road was built ?

[Keiji]

Can a moderator merge this with the other thread?

A quick look at the dates shows this thread's last post (before Gav's) was 2010, and the other thread started in 2011. So no confusion would arise there.

Now, I'm off to investigate Gav's idea

edit: wouldn't be worth it, I think. The reason I was so pleased to hear about the M5 J29 works (unlike everyone else?!) was because of the massive congestion through Sowton Ind. Est., and by providing the right turn movement out of Exeter onto M5(S), a lot of this would be removed.

I do agree that it's not the best idea, but my idea (thought up a couple years ago) was something else entirely - working from the arrangement before these works, close the north-facing slips, and add a new full access roundabout interchange about half a mile north, linking on the east side to the airport and new developments, and on the west side to Cumberland Way at a roundabout about mid way along its bend. Then make Cumberland Way a dual carriageway with a 40 or 50 limit like it should have been.

With this arrangement, traffic from anywhere in the Sowton area wanting the M5(N), or coming out of Exeter via the B3212 wanting to go either way on the M5, can use the new junction. Meanwhile, traffic heading between A30 and M5(S) has absolutely no traffic signals to contend with in either direction.

[DavidBrown]

Gav - that road isn't possible I'm afraid. At the M5 end you'd have to demolish the Exeter Chief's Sandy Park stadium, and at the A30 end you'd have no room left for access to Exeter Airport.

[PeterA5145]

Can a moderator merge this with the other thread?

A quick look at the dates shows this thread's last post (before Gav's) was 2010, and the other thread started in 2011. So no confusion would arise there.

Now done.

As a quick aside, if you want to ask the SMT for some aspect of forum maintenance, it's best to send us a private message rather than making a comment in a thread, which can easily be missed.

[Gav]

use either a squeezed roundabout under the M5, or reroute the M5 south off slip and place this movement through an underpass and link it to the M5 North off movement and take this combined flow to a roundabout to the west of the M5. Build a new A30 east to M5 south loop.....

junction improved...?

The other suggestion that I had for the A30 airport ? how would there not be enough room ? the road would be merging with the dumbell roundabout to the south of the A30 mainline - if you stopped up that local access then you could have the A30 off slip leave and merge direct with the new build.

[Keiji]

With signals and enough lanes on the roundabout, this would actually work quite well*! if it weren't for the fact that traffic coming out of the new developments now has to take a diversion to the airport junction (don't know if this would actually cause significant problems though).

*Relative to what's there now, and what was there before the works anyway.