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Brake Lights on Deceleration

SoCal Rob

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Totally understand it's on the drivers behind me to drive responsibly and pay attention. But in the age where everyone is texting, phones on their laps, folks not having insurance, etc. I've just become more and more paranoid of being rear ended.

On my other car (ICE) I added a brake light flasher where when I tap the breaks the middle light flashes a couple times to grab the attention of the drivers behind me.

A slight tweak, maybe 1 m/s less (guessing here) than where the current brake light deacceleration rate is at is all I'm asking for :)
I agree and I want to add that while it’s certainly going to be the other driver’s fault, it’s also certainly going to be a hassle for the person who’s hit. I’d like to avoid that if possible and I agree with you that the brake lights should come on with less deceleration.

I love OPD, have regen set to high and try to drive smoothly. There have been many times where I’m decelerating slightly to a stop, the brake lights are not on for an extended period, and someone is approaching very quickly. In this circumstance there is no way to smoothly activate the brake lights and, even worse with someone who may not be paying attention to you fast approaching, anything I do which is guaranteed to get the brake lights on means I have also increased my deceleration. Slowing down even faster means I get my brake lights on but I’m also robbing the other driver of some reaction time.

I’m fine with the brake lights staying off while coasting, but I personally think that any deceleration should activate the brake lights.

Beyond when they illuminate, I think our brake lights are too small. I understand they meet requirements, much like when they illuminate, but that doesn’t mean they’re truly good. I think Rivian knows this, too, since it seems like the rear turn signal behavior got changed on the Gen2 vehicles. I noticed when using a turn signal the large upper segment and small lower segment both flash. It’s nice to have a more visible turn signal, but the brake lights are what I’m counting on to keep from getting rear-ended by someone who isn’t paying attention.

I think Rivian should’ve divided the large rear/side lights into rear facing and side facing so they could have used them as parking/running lights like they are now, and used the large rear-facing portions as brake lights. I think they need to be split since I don’t think it’s permissible to have direct view side-facing brake lights. The clear area underneath (where the current brake lights are) would work great as a separate turn signal: I prefer amber but Iā€˜d settle for red.
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R1Thor

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That’s not precise. In one-pedal drive EVs you can lift off and get light regenerative braking where the vehicle is being braked, but the brake lights don’t come on unless it’s above a certain level. The question is if rivian sets the level correctly and if it possibly varies between vehicles because people report different things.
Anyone else remember the manual transmission?

Just me?

Because verily, unless you were also clutching, you were engine braking, which I did, all the time. I only used my brakes when I needed to, which was typically, ultimately, to stop (or in emergency braking scenarios).

It's not variable. It's a calculation. And I follow enough ICE vehicles and compare my brakes (due to silly conversations like these) to suggest it's a silly perception people have that the brake lights aren't coming on 'fast enough'/'soon enough.' It's a regulation and Rivian would risk fines and penalties if they weren't following DOT and NHTSA regulations.

Drive well!
 

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I cannot recall the exact deceleration rate but there is a NHTSA regulation that require regen braking to initiate brake lights if its slowing down more than the specified rate.
Interestingly, the Technology Connections YT channel had a video about this "Electric cars prove we need to rethink brake lights" two years ago. It seems that all Hyundai/Kia E-GMP platform cars did NOT turn on the brake lights unless the brake pedal was pushed. He indicates that there is NO regulation about regen braking turning on the brake lights in his pinned comment.
 

csharp

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That’s not precise. In one-pedal drive EVs you can lift off and get light regenerative braking where the vehicle is being braked, but the brake lights don’t come on unless it’s above a certain level. The question is if rivian sets the level correctly and if it possibly varies between vehicles because people report different things.
That is precisely what I am saying, maybe just didnt get my point across. It is possible (as designed) to lift your foot off the accelerator slightly so that you slow down, but you do not slow down quick enough to trigger the brake lights. That would be the exact same as removing your foot completely in an ICE and not triggering the brake lights.
It is possible to decelerate without triggering brakes in both an ICE and an EV.
 

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I’m actually appreciating that you can feather the pedal and not constantly active the brake lights: we drive winding mtn roads constantly and see the ripple effects of the constant brake lights in the turns.

I’ve also noticed the EVs are the biggest culprits - which is probably due to moderate or high regen rates/lack of coasting.

I’ve still got 2 manual trans in the rotation, having always had at least one for more than 40 years - following someone up our roads driving a similar car is much, much smoother and without all the brake lights.
 

southerncadesi

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Anyone else remember the manual transmission?

Just me?

Because verily, unless you were also clutching, you were engine braking, which I did, all the time. I only used my brakes when I needed to, which was typically, ultimately, to stop (or in emergency braking scenarios).

It's not variable. It's a calculation. And I follow enough ICE vehicles and compare my brakes (due to silly conversations like these) to suggest it's a silly perception people have that the brake lights aren't coming on 'fast enough'/'soon enough.' It's a regulation and Rivian would risk fines and penalties if they weren't following DOT and NHTSA regulations.

Drive well!
I complete understand the MT logic, I still own one myself (this is why I installed the brake flasher where I just tap the brake to engage while using the engine brake to slow down). All I’m saying is times have changed. More people are distracted than ever before, heavily reliant on GPS and more on their phones vs. 20 years ago. Hell our own R1’s have enough distractions on the screens themselves.

I also understand the traffic and hill climbs/decents that brake lights cause, don’t have a good rebuttal for that. Brake lights cause traffic. Period.

If the option to adjust when the brake lights come on (within legal limits) was available, I would appreciate it
 

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Just returned from a trip. Looking at the display in front of me, I noticed that my R1S tail lights lit up perhaps more than they should, I thought. Decelerating; slowing down noticeably; taking foot off the accelerator; don't know what I did or did not do; just kept thinking that tail lights were overly zealous alerting others. A good thing.
 

SoCal Rob

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Anyone else remember the manual transmission?

Just me?

Because verily, unless you were also clutching, you were engine braking, which I did, all the time. I only used my brakes when I needed to, which was typically, ultimately, to stop (or in emergency braking scenarios).

It's not variable. It's a calculation. And I follow enough ICE vehicles and compare my brakes (due to silly conversations like these) to suggest it's a silly perception people have that the brake lights aren't coming on 'fast enough'/'soon enough.' It's a regulation and Rivian would risk fines and penalties if they weren't following DOT and NHTSA regulations.

Drive well!
I think the big difference is that the driver of a car with a manual transmission can choose to activate the brake lights by lightly applying the brake pedal without changing the vehicle speed perceptibly. I used to do that all the time when engine braking in a manual just to keep the distracted person behind me from not realizing what’s going on.

I suppose I could do something similar in an R1 by using my left foot to brake lightly while keeping my right foot on the accelerator to coast and watching the IP graphic to see when the brake lights come on. That seems like a bad idea for several reasons.

On the other hand, asking for the brake lights to come on while decelerating strikes me as reasonable. I really don’t see a significant downside to the brake lights coming on a little sooner, especially with the opportunity to reduce rear end collisions. As I wrote earlier, our brake lights don’t seem large enough to be attention-getting. I infer that folks at Rivian think the same thing since they changed the behavior of the rear turn signals on the Gen 2.

I’m open to other suggestions, though, and I turn on my hazards when stopping quickly and unexpectedly (for those behind me) to mitigate the distraction factor. I just think all the work-arounds are only partially making up for the fact that the brake lights don’t come on early enough in some conditions.
 

R1Thor

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I think the big difference is that the driver of a car with a manual transmission can choose to activate the brake lights by lightly applying the brake pedal without changing the vehicle speed perceptibly. I used to do that all the time when engine braking in a manual just to keep the distracted person behind me from not realizing what’s going on.

I suppose I could do something similar in an R1 by using my left foot to brake lightly while keeping my right foot on the accelerator to coast and watching the IP graphic to see when the brake lights come on. That seems like a bad idea for several reasons.

On the other hand, asking for the brake lights to come on while decelerating strikes me as reasonable. I really don’t see a significant downside to the brake lights coming on a little sooner, especially with the opportunity to reduce rear end collisions. As I wrote earlier, our brake lights don’t seem large enough to be attention-getting. I infer that folks at Rivian think the same thing since they changed the behavior of the rear turn signals on the Gen 2.

I’m open to other suggestions, though, and I turn on my hazards when stopping quickly and unexpectedly (for those behind me) to mitigate the distraction factor. I just think all the work-arounds are only partially making up for the fact that the brake lights don’t come on early enough in some conditions.

I'm not going to fight you or anyone else on this. This is strictly my opinion and nothing more:
I don't think more brake lights will help.
I've been stuck behind vehicles with broken/over-sensitive brake lights (assuming a short, or similar). Too much is as bad as, if not worse than, not enough. Why? People become complacent.

People staring at their devices is an issue. On that we agree. However, you're not going to change their behavior because they see more red. I'd argue: they don't see it regardless. I think it's worse if they're surprised because suddenly the car is closer than they wanted to be to it, and there *wasn't* an obvious indication.

Which is how traffic works. Seriously: I commute way too much, and this comes up way too often that I've been paying attention. Vehicles of all types driving, and in a long-ass line of traffic as far as the eye can see, there are practically as many easing off the throttle and timing their driving just as much as there are those who use the brakes and their brake lights come on.

I think as long as things are predictable, that's really the only winning here, and if the automakers are following the rules, then it's gravy.

Just my unsolicited .02. Again, I'm not here to start arguments (at this point anyway :D). I'm just very certain that this is not some magically unique condition that exists in BEVs, or Rivian, or MTs only. Sincerely. Next time you're in traffic look around, and if you still believe you're right, show me your dash cam footage and I'll show you mine. {and for anyone who actually needs to hear this: PUT YOUR F'ING PHONE DOWN AND PAY ATTENTION TO THE ROAD. NOTHING is that important. It can wait until you arrive or pull off the road.}

TL;DR: too much of a thing is just as easy to ignore as not having a thing.
 
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VSG

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I'm just very certain that this is not some magically unique condition that exists in BEVs, or Rivian, or MTs only.
Yes, exactly this.
I think the whole "Brake lights don't come on" trope is probably the second-biggest piece of misinformation about EVs, second only to how they "catch fire" all the time.

I understand the anxiety about driving and being hit from behind when you have no control, but your Rivian/EV/ICE vehicle is not the cause of that, and EVs don't get hit from behind any more often than ICE vehicles. We certainly hear about re-ending accidents more than others, because they are one of the largest categories of accident but also because the people posting about these accidents are clearly not at fault. You're not going to hear a lot of voluntary confessions from people who were at fault - posts are going to be almost entirely from people who were hit and couldn't avoid it. That means a lot of rear-ending posts ...

When I got rear-ended a few years ago (in and by an ICE vehicle), I was stopped at a stop light and had been there for a while. There were two people in front of me. Wide open and lots of visibility, and the driver who came up from behind me was able to see me stopped a block away, if she had been looking. I saw *her* in my rear-view before it happened, and she was reaching down to the floor to pick up her phone. Nothing I could do, and no amount of flashy lights or anything else would have saved me.
 

Singletracker

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I’m actually appreciating that you can feather the pedal and not constantly active the brake lights: we drive winding mtn roads constantly and see the ripple effects of the constant brake lights in the turns.

I’ve also noticed the EVs are the biggest culprits - which is probably due to moderate or high regen rates/lack of coasting.
Yes. It drives me nuts following people through the mountains and having their brake lights constantly flashing for no real purpose. Often, it’s just inept drivers riding their brakes. In the case of some EV’s, it’s the system setup. If you don’t want to be one of those annoying drivers, you can disable the Rivian’s Blended Braking feature that constantly rides the brakes on down grades. I did this and see my brake lights activating way less often. Now, they donā€˜t come on every time I coast a little or mildly decelerate.
 
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superfly_snook

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Brake lights that come on just because someone is not accelerating is a dumb idea. So what are you all proposing here? A different deceleration standard? If you think the standard is set inappropriately write a letter.
Anyone else remember the manual transmission?

Just me?

Because verily, unless you were also clutching, you were engine braking, which I did, all the time. I only used my brakes when I needed to, which was typically, ultimately, to stop
Not just you - this exactly - and in our E92 BMW M3 lifting off the gas completely at anything over 4500rpm (redline was over 8000) was roughly the equivalent of lifting off the accelerator in our R1S quad - instant deceleration to the point you would flop into the restraint belt if you weren’t ready for it.
 

Singletracker

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Anyone else remember the manual transmission?

Just me?

Because verily, unless you were also clutching, you were engine braking, which I did, all the time. I only used my brakes when I needed to, which was typically, ultimately, to stop (or in emergency braking scenarios).
indeed, I do remember. Heck, I didn’t stop the practice at manual transmissions. I would do the same thing with my automatic transmission vehicles. If I can see ahead that the light is red, I often do most of my slowing down by using the transmission, rather than slamming on the brakes at the last minute. It’s amazing how long one can go between brake pad changes, when you are not constantly riding the brakes. I have a vehicle, right now, that has over 150K miles on the original pads. I’m serious! Maybe, if people realized how much it was costing them to service their brakes and that they could dramatically extend that service interval by simply using them less, they would stop their manic driving habit and learn to be better drivers. I drive in the mountains a lot and, boy, there are some seriously crappy drivers up there. I was following a guy the other day and his brakes lights were more like strobe lights, even on the straight aways. He must do a brake job every 50k miles.
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