Variable turn lane, Colnbrook

[Bryn666]

https://goo.gl/maps/etS6x62jEEP2

This is a weird one. It doesn't appear to see much use, but do any locals know the story behind this?

[RichardA35]

https://goo.gl/maps/etS6x62jEEP2

This is a weird one. It doesn't appear to see much use, but do any locals know the story behind this?

Pretty sure it's on the diversion route for M25 J15-14 S/B closure (along M4 west then back east on A4 then south on A3044)

[Bryn666]

https://goo.gl/maps/etS6x62jEEP2

This is a weird one. It doesn't appear to see much use, but do any locals know the story behind this?

Pretty sure it's on the diversion route for M25 J15-14 S/B closure (along M4 west then back east on A4 then south on A3044)

That would likely explain it. It seems rather an expensive way of achieving it (and in conflict with the road markings), but I could see this being a viable proposition at a number of junctions where flows seem to switch about during the day.

[WHBM]

Local to my regular journeys.

It's been there for years, only seems to get switched in morning peak (in fact notably early, about 0500-0700) when there is a substantial right turn flow of staff going to Heathrow. Rest of the day the mainline predominates. The regulars seem to handle the variability fine. Don't quote me, but I think it got put in with the S.106 traffic management spend when British Airways opened their Waterside HQ off to the left, which required extra stages on an already congested junction.

Is it unique ? Can't think of another.

[Harri]

There is a similar sign at the bottom of the A4216 in Swansea, although I’ve never seen it in use.

https://goo.gl/maps/1SurPRn8Uu72

[jimboLL]

There is a similar sign at the bottom of the A4216 in Swansea, although I’ve never seen it in use.

https://goo.gl/maps/1SurPRn8Uu72

I believe this has now been removed (probably because it was never very well observed) and the middle lane is permanently straight on or right turn.

Middle lane used to be left turn only in the morning and s-o/right later in the day, but left-turners would often find themselves stuck behind an erroneous right-turner when the left filter came on.

[AndyB]

Bridge End, Belfast.

When the M3 is closed the prisms can be rotated to show a yellow sign with lanes 1-3 ahead only and lane 4 straight on or right. However, even though this was established as the default plan when installed in 1994, it's now extremely rare.