Slowing down to overtake.

Some people are very egalitarian minded and get defensive when individual age cohorts, especially older people are singled out for criticism. TBH all age groups act the bollix on motorways and it’s not all down to training or knowledge, sometimes it’s just down to pure stupidity and self interest.

My young lad was a passenger with a newly qualified driver recently, proudly displaying his N plate, who was hogging the motorway outside lane even with cars behind him and an empty left lane. When asked why he didn’t move left he said fcuk em Im going quick enough. Just an entitled bollix no amount of training could overcome

I think it's 2 as well. Very common on the M7/M8. Very annoying.

I suspect a lot of people genuinely have no concept of what speed they're doing - like when a speed van comes into view and they dive on the brakes despite the fact they weren't over the speed limit anyway.

Or the 80 in a 100, 80 in an 80, 80 in a 60 club members.

While I will jokingly say that it is #1 it's most likely #2

But there is a growing number of people who are driving our motorways at 100-110 and don't speed up when overtaking - meaning they are overtaking the vehicle in front of them at about an extra 1-2km/h. You might notice this more when using cruise control, specifically adaptive, because you're noticing more of what's happening on the road. As annoying as it is you're likely becoming a more attentive driver

Agree, it’s what happens when drivers overly dependent on car’s safety/driver assistance systems rather than actually be in control of driving the car. I think it’s more problematic on busy motorways when drivers using acc can’t overtake a slower car on time and their car slows to match the speed of car in front. When a gap appears the driver pulls out and it takes a second for the acc to start accelerating up to set speed. If you coming up behind this car you’re going to have to slow down to match this speed and it appears the car in front is matching the car it’s overtaking.

My M3P can also sometimes apparently get confused if driving what it considers too close to a truck being overtaken and matches the truck speed rather that continue to accelerate. In addition the acc is quite lethargic at accelerating up to speed which can be frustrating especially for a car behind approaching at 120kph. Of course the solution, if you’re interested in minimising annoyance to other drivers, is to hit the accelerator to force the car up to speed more quickly. Of course most drivers are oblivious to other drivers which is why you get those dwadling on the outside lane, including truck drivers attempting to overtake another truck while climbing an incline at a delta of 1 or 2kph.

Except the OP said it's people slowing down AFTER they've moved into the overtaking lane. So that's not ACC.

Might depend on the car but my ACC responds pretty quickly to a clear lane in front.

True but sometimes driving errantly has unintended consequences resulting in other drivers taking evasive action which can cause accidents with the original safe driver obliviously driving off safely into the sunset.

Such drivers would logically just not overtake at all.

I’m theory no but of course the theory test doesn’t always materialise in reality. It doesn’t have to be a hysterical reaction…why does everything have to be so dramatic? There are more issues on motorways that an overtaking driver matching the speed of middle/left lane driver. It’s all about context, something ot can be difficult to experience in a theory test