I always on joining the motorway off a slip road with 2 lanes, I will choose the lane that's emptier and join at motorway speeds when its possible, hate the drivers that crawl on slip road panic and go to the end at 40 and jump out into traffic doing 70 idiots

Jeez that is a strange one, looking on google does it continue as the fast lane? And is 50mph leading upto it?

I can't tell whether it's J17 or 18 but it's from A82 Gt Western Road onto M8 Eastbound. Yes, you join as the outside lane in a 50mph limit (and IIRC that stretch has been 50mph since the road opened) (The reverse of the outside lane being the Westbound entry and exit from 15 to 17 or 18 is also true). That outside lane becomes an exit slip at J15 Townhead (to A803). J16 has no Eastbound exit or Westbound entry slips.

The 50mph limit continues out to J13 (M80 to Steppes and Cumbernauld). At this point the road is now 5 lanes wide, with L1 and 2 serving the M80 and 3 to 5 inc continuing as the M8. The M8 speed limit rises from 50 to 60 here.

The 70 mph limit doesn't start Eastbound until close to J8 (M73). I can't remember the exact location, but the road is still 3 lanes at that point.

A very confusing section of road. I was doing a steady 50-60 after joining the slip from the A82, and yes I know the limit is 50 - however the fact that I was in a line of cars that were all doing the same steady speed - and a large number of cars (literally dozens) were undertaking, emphasises the difficulty of the stretch of road. to merge into lane 3 I would have to have increased the speed.

None of this is an excuse for my "blond moment" but purely emphasises bad road design.

...however the fact that I was in a line of cars that were all doing the same steady speed...

Well at least you weren't the only one.

I know what it feels like after a tough day at work when you are following a line of other cars at a steady speed, sometimes you just 'switch off'!