Auto Pilot Won’t Undertake?

[AndyEVTM3]

Hi,
I was driving home last night in the dark on an unlit 3 lane A130.
I was in lane 1, which was clear ahead for a long way and I had the auto pilot cruise control set to 70.
My car (model 3 2022) was happily driving at 70 when it started to approach a car in lane 2 doing about 65.
My car then slowed down to the same speed and sat behind the car which was in lane 2. I remained in lane 1.
The other car was clearly in lane 2 as it was shown on the display in my car and there were no other cars around. I.e just me in lane 1 and the other car in lane 2.

Question is was my car refusing to undertake or is there another reason it slowed down?

Thanks for any advice or info.

 

[MrBadger]

Question is was my car refusing to undertake or is there another reason it slowed down?

Urm, it’s illegal to undertake in that scenario by sounds of it. With 3 lanes you could have legally overtaken.

 

[Adopado]

Hi,
I was driving home last night in the dark on an unlit 3 lane A130.
I was in lane 1, which was clear ahead for a long way and I had the auto pilot cruise control set to 70.
My car (model 3 2022) was happily driving at 70 when it started to approach a car in lane 2 doing about 65.
My car then slowed down to the same speed and sat behind the car which was in lane 2. I remained in lane 1.
The other car was clearly in lane 2 as it was shown on the display in my car and there were no other cars around. I.e just me in lane 1 and the other car in lane 2.

Question is was my car refusing to undertake or is there another reason it slowed down?

Thanks for any advice or info.

It was following the Highway Code rules. Others may know it it's different with solid lanes of slow moving traffic ... in which case it's OK to undertake.

 

[The_Cable_Guy]

as above its illegal, my car has done it several times, so must be programed into AP, and i still regularly do it manually

As i absoluately lothe people who sit in the middle or outter lanes when all the others are clear.

 

[AndyEVTM3]

I’m ok with undertaking rules and know I should have overtaken, but I’m just curious if the car is configured to apply these rules?

 

[WllXM]

Yes had the same behaviour. My guess is the car is able to see when the lanes are congested, and when they're not, will refuse to undertake as it's against the code.
Obviously the car in lane 2 is a moron, but you still should cross all 3 lanes to do a proper overtaking... And I completely understand that when AP is enabled, there is a reluctance to 'break everything' and hear all the 'bongs' just for someone who cannot drive in the proper lane...

 

[Adopado]

I’m ok with undertaking rules and know I should have overtaken, but I’m just curious if the car is configured to apply these rules?

It is.

 

[MrBadger]

I’m ok with undertaking rules and know I should have overtaken, but I’m just curious if the car is configured to apply these rules?

Yes above but according to the manual only above 40mph and, possibly not in the manual, as long as you have not previously overridden the speed with foot on accelerator - if you have it will merrily try and undertake irrespective of speed.

 

[WllXM]

Yes above but according to the manual only above 40mph and as long as you have not previously overridden the speed with foot on accelerator - if you have it will merrily try and undertake irrespective of speed.

Okay so I stand corrected with my previous answer, makes more sense that this has to do with a <40mph speed and not Tesla Vision actually analysing if the congestion is a 'continuous lane of traffic' as per the Highway Code to allow undertaking.

 

[AndyEVTM3]

Thanks for the explanations.

 

[Durzel]

Makes more of a point sweeping out to lane 3 and all the way back to lane 1 again, right in front of them.

 

[The_Cable_Guy]

Makes more of a point sweeping out to lane 3 and all the way back to lane 1 again, right in front of them.

Yet 8 out 10 times when you do that they are still so unaware and probably think " whats this wanker doing"

 

[Durzel]

Yet 8 out 10 times when you do that they are still so unaware and probably think " whats this wanker doing"

Yeah quite likely.. it's more of a "I've made my point" thing when I've done it. If you just undertake them it doesn't have quite the same theatre.

 

[WannabeOwner]

I’m ok with undertaking rules and know I should have overtaken, but I’m just curious if the car is configured to apply these rules?

Yes, that's my understanding. But you can press the accelerator to tell it to "proceed"

 

[init6]

I’m ok with undertaking rules and know I should have overtaken, but I’m just curious if the car is configured to apply these rules?

But not curious enough to look in the manual

Passing Vehicles in Non-Passing Lanes​

When cruising 50 mph (80 km/h) or faster, Model 3 must be in a passing lane to pass a vehicle. If you are in a non-passing lane (to the right of a vehicle in right-hand traffic, or to the left of a vehicle in left-hand traffic), Traffic-Aware Cruise Control prevents you from passing other vehicles. Instead, Model 3 slows down to match the vehicle’s speed as if it were in the same lane. If you press the accelerator pedal to pass a vehicle, Traffic-Aware Cruise Control allows you to continue passing vehicles when cruising in the non-passing lane, until you either change lanes or cancel and resume cruising (it then prevents you from passing vehicles in a non-passing lane again).

 

[Medved_77]

But not curious enough to look in the manual

This behaviour is important to understand for dual carriageways where crossing the central reservation is allowed, such as the A90 between Dundee and Aberdeen.

Caught me out in the early days of ownership.

 

[Pink Duck]

This behaviour has also frustrated me sometimes when in lane 2 of 2 and AP refuses to pass a car in lane 1 just after a highway exit ramp (usual Armco central reservation). Might be mapping issue or a transient behavioural outcome of applying US-trained NNs on UK roads.

 

[init6]

This behaviour is important to understand for dual carriageways where crossing the central reservation is allowed, such as the A90 between Dundee and Aberdeen.

Caught me out in the early days of ownership.

We've been discussing that road on another thread - [UK] 2023.2.x

 

[Medved_77]

We've been discussing that road on another thread - [UK] 2023.2.x

Yes, AP slows for me too passing the trucking place. But in addition, on that road, if someone is indicating right to cross over the dual carriage way through the turning in the central reservation, AP will also slow to match the speed of the car slowing to turn right as it thinks you're undertaking in the slow lane.

 

[Overworked]

This behaviour is important to understand for dual carriageways where crossing the central reservation is allowed, such as the A90 between Dundee and Aberdeen.

Caught me out in the early days of ownership.

That might be me then! I have my own deceleration lane to an offslip for a right turn lane to cross the A90 dual carriageway on that stretch. I indicate right in good time and slow to about 40 mph to get into the right lane and cars at 70mph need to pass me on the left. I indicate and slow in good time as most wont realise that there is an unsigned right turn slip road ahead at it turns into a private driveway and not a public road.