Using the electronic parking brake or the P button whilst driving at speed??

[wandle MG4 trophy]

I’m curious about what would happen if I pulled up the Electronic Parking Brake (the lever next to the gear selector) or pressed the big P button whilst driving at speed.

The reason for asking is that I may be accompanying a very inexperienced new driver and wonder what the best response from me would be if they lost control of the car or were about to hit something. Obviously this would be a very last resort as an intervention like this could in itself be very dangerous.

As an experiment I tried pulling up the brake lever when I was driving at a 4 mph and the car came to a very sudden stop. Would the car do a controlled emergency stop at higher speeds? What would happen if I pressed the P button at speed? Thanks in advance.

 

[MG Clive]

I’m curious about what would happen if I pulled up the Electronic Parking Brake (the lever next to the gear selector) or pressed the big P button whilst driving at speed.

If you pull the EPB lever, the rear brakes will be applied, and the vehicle will stop, but only if you pull and hold the lever, if you just flick it up and let it go, nothing will happen.

Not sure about the P button, but I don't think the car will allow anything to happen, it would be very dangerous.

 

[Tuareg]

Why don't you try it yourself on a quiet road or big empty car park. For your new driver, set the drive mode to 'ECO' before they pull away.

 

[GaryMG4]

Hopefully the 'P' button will have a software interlock, otherwise inserting the pawl will probably destroy the gearbox. Of course that's if you trust the software!

 

[the2ems]

I’d be more worried about allowing a very inexperienced new driver to drive at speed in what appears to be YOUR car

 

[securespark]

This is something I too have always wondered, but from my perspective as a passenger and if the driver had a medical emergency: in an older car, I could knock the box into neutral and apply the manual handbrake gradually notch by notch, then steer the car gently to the side. With an electronic set up of course, there are no graduations.

Unless, of course, the software would understand that no sane human being would want to apply full parking brake at 70 mph and that there must be an emergency and, let's say, if the EPB is held up, the car would apply the brakes gradually to bring the car safely to a halt, hopefully at the same time showing brake lights and hazards....

Even better, if the software could be configured such that in such an emergency, all the brakes were activated, not just the rears, even better.

That is how I would set the car up, if I were the designer.

 

[securespark]

I’d be more worried about allowing a very inexperienced new driver to drive at speed in what appears to be YOUR car

Have you never put your kids on your policy where you sit in with them while they drive when they are learning?

We did with all 3 of ours. No worries at all.

 

[Kithmo]

I may be confusing this with the Prius or the ZS EV, but ISTR reading somewhere that pressing the gear selector "P" at speed puts the car in neutral "N"
On the MG4, pulling the "P" switch up will operate the rear parking brake fully, which will slow you down rapidly, the slower you are going the more abrupt the stop, basically the same as pulling the handbrake lever full on with a manual handbrake.

 

[Seajays]

Pressing P doesn't do anything except beep at you if you're moving.

Pulling up the electronic parking brake is for emergency braking, in case of brake failure... from the manual:

 

[tsedge]

Generally speaking, car makers have thought about all these scenarios, so you won't break anything by selecting an unusual mode at the wrong time. Remember there is no physical connection to the car, it is all mediated by software and electronics, which will protect the car systems.

 

[the2ems]

Have you never put your kids on your policy where you sit in with them while they drive when they are learning?

We did with all 3 of ours. No worries at all.

No, definitely not. That’s the best way for them to pick up bad driving habits. They all went to registered driving instructors.

 

[Bam Bam]

Have you never put your kids on your policy where you sit in with them while they drive when they are learning?

We did with all 3 of ours. No worries at all.

My parents did this for me, but then that was learning in a manual ICE car where you have to practice with bite points and gears and things like that.

If someone is driving an automatic electric car then they should be able to focus on the driving technique earlier on.

 

[securespark]

No, definitely not. That’s the best way for them to pick up bad driving habits. They all went to registered driving instructors.

They had driving lessons as well!

 

[dsimpkins]

They had driving lessons as well!

My mother taught me the basics of clutch control, steering, braking and gear changes until these became muscle memory. Then handed me over to a driving instructor to polish my driving skills. After first lesson I was asked "Have you booked a test yet?" "No" I replied. "Why not?, you are ready". I taught my daughter the basics, practising on an industrial estate on the weekends, same as I did with my mother. Her first lesson, the instructor said exactly the same thing to her, as mine said to me.

Also, have you seen the price of driving lessions these days!!!

 

[ReintjeWA]

I just tested this on a stretch of empty road at 50 60 kph which is like hard braking really, and from 70 80 kph it becomes more of an emergency stop (ABS triggered). But to be fair you would do this if stopping was an emergency, so…

The most interesting discovery though was that as soon as you let the EPB button back down, the car accelerates away again. So for whoever needs to do this for real in the future make sure you change the gear selector to P before you let go.

 

[MG Clive]

I do it to clean the rust off the rear brake discs.

 

[securespark]

So for whoever needs to do this for real in the future make sure you change the gear selector to P before you let go.

l guess you could also put it in neutral?

Was the reason your car accelerated because cruise was on?

Back to my medical emergency scenario, presumably cruise (and drive) could be disengaged by selecting neutral.

 

[ReintjeWA]

l guess you could also put it in neutral?

Was the reason your car accelerated because cruise was on?

Back to my medical emergency scenario, presumably cruise (and drive) could be disengaged by selecting neutral.

No cruise control, but kept my foot on the accelerator. I guess neutral would have the same effect but perhaps could allow the car to roll? I would’ve expected the electronic parking brake to come on after holding the EPB up, but it doesn’t.

You can definitely switch to Neutral while driving, I’ve done this several times to clean off the brake discs (no regen braking in neutral).

 

[securespark]

Cheers.

So in an ICE car in neutral, depressing the accelerator would rev the engine.

I guess in an EV, the software would ignore the driver's input, if the selector was set to N?

 

[ReintjeWA]

Here is the dashcam footage, I did 60 kph and 80 kph apparently. During the second one you can hear some clicking/thumping noises which is the ABS activating. And as you can see the car takes off again as soon as the EPB button is released.

MG4 EPB activation at speed

MG4 EPB activation at speed

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