Did I undertake?

[TimesRwo]

Not a big deal (I don’t think), and whilst I did strictly speaking undertake, I don’t know if this counts! So grateful for guidance.

I was on the motorway, where the left lane was going to pull off to the M25 in around a mile’s time and the right two lanes were going to carry on.

I needed to get onto the M25 so went into the left lane doing 70. There were then two cars in the middle lane / left lane going straight ahead doing about 60. No other cars around in sight.

I therefore carried on doing 70, being I undertook those two cars, even though my lane was for a different direction. I wouldn’t have thought much of it but one of the drivers started honking and shouting at me. Genuinely unfazed by his aggression, I just wanted to know if I was meant to hold back and not undertake.

I did the same thing coming off the motorway later on in the journey, where the exit lane which again runs for around a mile was mostly clear, but the 3-4 lanes of the m25 was busy. I drove past all the cars.

Just to clarify, it’s not one where you’re immediately at the junction, you drive for around a mile in that lane before you get to the exit, but the signs above are very clear that the left lane is for X road, and the right lanes are for carrying on.

Thank you!

Regardless of the law, common sense tells you at 70mph and still a mile from the exit it is not worth the risk. A bump at that speed from someone pulling into the left lane because they don't expect you there (I know they should still look) is not going to be pretty.

@plasticpens
She didn't manoeuvre or accelerate to pass the vehicles and drove to the speed of the cars in her lane. That's not undertaking.

So I’ve had a couple of photos of where the line changes, and then another one of how the road looks for about a mile before the lanes physically separate. So the lane markings do differ, but they are all still one road.

I know it doesn’t matter for the question at hand, but the two cars in the middle were middle lane hogging as they were in that lane for a while before I approached!

The picture clarifies you were not undertaking. The lane is separated from the main carriageway

It is if cars are going slower in a lane to the right.

However as the picture shows OP wasn't undertaking at all.

I don’t see it was undertaking if the markings have changed but I have always wondered if it’s undertaking or not (still do exactly what OP did)

Apart from anything else, the honking and other bollocks means that you'd encountered a slingshot driver - the ones who dawdle along and then yank the car across the lanes at the very last second endangering themselves, their passengers and everybody else. Fortunately, this one actually checked their rear view before they caused yet another near miss.

Whilst it sounds like you were fine because you were already in the specific lane for coming off and they should have been continuing straight on (and therefore what you did was of no consequence to them), there are enough of these wankers around for it to be a risky thing to do - as an ex biker, I've seen far too many like it to want to trust they aren't about to cause a rapid dismount and trip to the nearest A&E or mortuary.

@TimesRwo OP Lucky for you I have checked with a Traffic Officer and you're good!

My DH is a trainer for driving instructors and we had this conversation last week. I always thought that it was when the marking changes but it is actually when the lane officially splits into another road signified by these horizontal bits just before the junction (sorry not sure how to describe it). Only then it is classed as a separate road.

The reason being is that a driver can move to the left at any point even after lane marking changes but they can't when this marking appears.

At 70mph, OP will reach the junction/split one mile away in less than 60 seconds. That doesn’t give her time to overtake the dawdler in the middle lane and then cut back in across two lanes to make her exit before overshooting it.
I have a similar situation coming off the Queensferry crossing on the M90 heading into Edinburgh. Traffic crawling in the middle lane, when I’m in the left lane heading for the A90 city centre turn off. I simply continue at a steady 70mph, and if that means I go past them, so be it. All the traffic does it, nobody seems bothered by it. The dawdlers don’t want to end up going off at the exit, so avoid the left lane, and those of us who do, zoom happily past. It’s a non problem.

I would say it's still undertaking

Undertaking is not advised because its dangerous, cars aren't expecting it and you can often be missed, a car moves left and hits you. In your first scenario this could happen therefore it would be inadvisable to undertake.

In the second scenario if the traffic on the main road is slow moving then its reasonable to undertake as you did.

I know what you mean and I do it all the time. If they were going to take the junction then they’d be in the left lane. So it’s fine. Other driver was being rude. If he didn’t like it he should have moved over to the left.

If there is a solid white line between your lane and theirs then you can go faster, ie; undertake. If the white line is broken, which I assume it was because it was a while before it actually exited then you cannot undertake. Just because you're in the lane to move off you're not yet in a new road. Others may have missed the signs to turns off and are still able to do so. If you undertake (as many wrongly do) then you'll cause an accident and at 60-70MPH that won't be pretty or end well.

You encountered an idiot. Pay them no mind.

this makes sense

You didn't do anything wrong.