Northbound M5 at Jun 4a goes to 1 lane-why

[Steviesam]

Been using the northbound M5 recently and at junction 4A, the 4 lanes split.

2 for the M42 and 2 for M5.

But the outside lane of the 2 for the M5 is filtered into 1, causing some considerable tailbacks, only to immediately return to 2, then 3 lanes. No roadworks are there.

Anyone know why?

[smithyithy]

To encourage traffic to use the M42 rather than the M5 heading north, thereby reducing traffic travelling through works at junction 1 and 2 (Oldbury viaduct).

Traffic assessment here: http://assets.highwaysengland.co.uk/roads/road-pro... pages 6 / 7 cover the area you're referring to I think

[Fastchas]

It holds back 3 lanes of traffic from ploughing on to the jct 2 roadworks. Highways Agency reckon it's better to hold it back there and let it filter it into the remaining M5 at a slower rate.

[smithyithy]

Fastchas said:

It holds back 3 lanes of traffic from ploughing on to the jct 2 roadworks. Highways Agency reckon it's better to hold it back there and let it filter it into the remaining M5 at a slower rate.

It's volume as much as speed of traffic, the desire is to have traffic use the M42 to get around the Birmingham box rather than going up the M5 through the works, as that also has knock-on effects to surrounding roads, not just the motorway.

The report above suggests it's largely had the desired effect.

I work for Kier Highways so have to state that I'm not speaking on behalf of them or anyone else

I've had little if any involvement in the M5 Oldbury works though, I stick to the A-roads which are more fun

[Steviesam]

I see, that does make sense.

I use the M5 then M42, so doesnt really affect me, but I just wondered.

[Fastchas]

Steviesam said:

I see, that does make sense.

I use the M5 then M42, so doesnt really affect me, but I just wondered.

Doesn't make sense when you want to get to Jct3 and have to endure 40min hold ups!

[Muddle238]

I've been wondering what this lane closure at 4a is for a while. In peak times while going southbound [luckily], I've seen the tailbacks for 4a stretching all the way down to J5. As mentioned above it's a mega pain in the arse, especially if you don't travel as far up as where the actual roadworks begin.

I often use that bit of motorway but refuse to use M42/M6 instead, not unless HE offer to reimburse the fuel cost of the extra mileage. Also the M6 is a god-awful motorway, especially the section between Coleshill and Wednesbury.

The M5 southbound also has a lane closed prior to the works, just after it splits from the M6. Unfortunately this often has tailbacks onto the M6 itself, seen a few crashes there. Also the tailbacks are through the section with the "lane closed in 800yrds" .."600yrds" ..."400yrds" and so on, despite the merge in turn signs you either won't be allowed in at the merge, or you'll be stuck behind a road captain blocking the lane half a mile ahead anyway.

So yeah, the sooner they finish messing with the M5 the better, can't be long now. Was supposed to be done and dusted by Autumn 18 according to the signage.

[Puggit]

Many vehicles use lane 2 and then cut in to lane 3 at the last minute, as the 1 lane of M5 north traffic starts moving again.