[georgecalm]

There's a great video from "Technology Connections" covering one-pedal driving here [1]. The gist of it is that one-pedal breaking doesn't have a great way to control the break lights, making it difficult for the cars behind you to recognize that you're slowing down, which can cause accidents.

[1] https://youtu.be/U0YW7x9U5TQ?si=7XFO_ZHIwUjd-3Sm&t=195

[eurleif]

This is only a problem in some EVs. Teslas, for example, illuminate the brake lights correctly when regenerative braking is used. The pinned comment on the video also suggests Hyundai may have fixed this on their cars by now, although I don't know whether they followed through.

[numpad0]

IIRC the industry went from hard regen "may illuminate" -> "shall not illuminate" -> "must illuminate". Some cars designed and/or type approved when the middle one was regulatorily current follows it.

[smileysteve]

"Correctly".

Manual transmissions (and sport shifting automatics) of most cars from 1904-2024 of sports coupes to trucks don't illuminate the brake lights when engine braking. Drivers following cars should be basing most decisions based on relative speed based on these existing.

If you were to follow behind me in my 2004 manual sports car or a 2021 automatic and only applied brakes when I did, you'd be speeding in my neighborhood and rear ending me, as I keep both in second gear and it keeps me at 20mph.

[m463]

> Teslas, for example, illuminate the brake lights correctly when regenerative braking is used.

lol. my definition of "correctly" differs from tesla (and probably the engineering groups that recommend this).

I think it should be a setting so that you can make it come on only when you touch the brake pedal.

on twisty roads, this is especially annoying.

You are basically crying wolf, and other drivers will be desensitized to your brake lights, possibly when you really use them.

[eurleif]

Having no brake lights for regenerative braking sounds incredibly dangerous. Regenerative braking can slow the vehicle down quite quickly, and as the name "one-pedal driving" suggests, it's common to barely touch the brake pedal at all.

Perhaps a better version of your complaint is that Tesla has made the threshold for the brake lights too sensitive; but I would be curious how much observation went into drawing that conclusion.

[smileysteve]

I drive my manual and auto cars like this, downshifting instead of using the brakes and preventing dangerous acceleration. I often only use the brakes from 20mph and below (though may touch them during a downshift)

Thinking it's more dangerous is odd as it's a great example of fail safe.

[mikestew]

You are basically crying wolf...

I think you misunderstand, or just don't understand at all, how regenerative braking or one-pedal driving works.

[CorrectHorseBat]

Why would it matter to other drivers whether you brake using regen or your brakes? Either way you're slowing down.

[Symbiote]

On a twisty road, having the driver behind you back off a bit more sounds like a benefit.

[rootusrootus]

Wasn't his whole problem with one particular implementation of one-pedal driving, the Ioniq 5? As I recall, it was poorly implemented and had a relatively common use case that would allow you to stop without the brake lights ever coming on.

This isn't really a problem that other EVs have had. The brake lights come on when you slow down, just as if you had used the brake pedal. It's mostly as easy as triggering at a certain amount of kW generated.

[bdcravens]

I can't speak for the state of the problem, but the Kia EV6 is a sibling to the Ioniq 5, and I would assume had/has the same issue.

[HackeNewsFan234]

> Wasn't his whole problem with one particular implementation of one-pedal driving, the Ioniq 5?

Yes. I watched that Tech Connections video a while back. In that implementation, his car would slow down too quickly without brake lights. I think it would get down to something like 15 mph from 55 before they'd come on, yet the deceleration was at least as rapid as casual braking.

I agree with the Tech Connections example; I have no comment on other EVs.

[oh_sigh]

I can go from 75 to 5 mph in my ICE with the brake lights never coming on. Or, I can maintain 75 mph with my brake lights on 100% of the time.

But really, there should just be a standard - it seems obvious and easy for EVs to get it right: If deceleration is > X m/s^2, then brake lights are on.

[WelcomeShorty]

The European Union has a regulation that requires EVs to illuminate their brake lights anytime the regenerative-braking system’s deceleration rate exceeds 1.3 meters per second squared, or about 0.13 g.

[throwaway2037]

Cool. How did you know this incredibly specific value? Assuming that it is correct, how was it determined? I would like to learn more.

[WelcomeShorty]

Simply because I've been driving TVs for a while and "in the beginning" when there was no rules for brake lights to be turned on when regenerative breaking, I got into trouble (German highways) with cars driving behind me and not being able to anticipate / react fast enough when I used it.

I quickly learned to force the break lights and started to follow this issue closely. That's how I became aware of the number.

How the EU saddled for 1.3 and not 1.2 or 1.4 is beyond my knowledge.

[gnicholas]

Unless I downshift using paddles, my ICE will coast forever from 75. My PHEV, on the other hand, will slow down much faster. I want my PHEV to illuminate the brake lights if I'm decelerating above a certain rate, just as you suggest.

It never occurred to me that I might want my ICE to do the same, but I suppose it would be helpful if I'm heading downhill and downshift without touching the brake.

[perilunar]

How will we then be able to tell which drivers are ignorantly riding their brakes all the way down a long hill, versus the drivers using engine braking?

[tristor]

By listening? Engine braking makes noise, which is why it’s banned in some areas.

[yunohn]

If you’d read TFA:

> Brake lights on your electric car will automatically illuminate when you decelerate the vehicle and will remain on when the vehicle fully stops.

[InCityDreams]

>Brake lights.....will remain on when the vehicle fully stops.

Mmmm, nothing better than a dark, rainy evening in November in a city after a long day at work and you're stuck for minutes on end right behind a car with red lights burning into your retinas. Wankers.

Thanks engineer bastards.