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Regen and Brake Lights - Highway Issue

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It's not about being polite to tailgaters, it's that it sends mixed messages to even normal drivers who use your brake lights as an indication that there is something going on in front of you. A brake flash is annoying no matter how far back you are behind someone. If I can't see through you and your brakes flash momentarily, I'm thinking there could be a massive slowdown and so I'm likely to be ready to tap my brakes. When this happens for a few cars in a row, backups and traffic jams start for no reason (and probably one of the biggest reasons for traffic jams is this situation).
I guess I consider this a tempest in a teacup. We have had accordion-style traffic jams LONG before EV's have had regen-activated brake lights.
Strider-- even with barely moving my foot, regen can hit up to 30 and flash the brake lights on. There is no level of smoothness that can fix this.
In my and Tesla's opinion, if you are regenning more than 30kW then you are slowing at a sufficient rate to warn others behind you. As I've said to numerous people, regen is not the same as downshifting an ICE. My last car was a C6 Corvette w/ a manual transmission. It's a 6.2L V-8 which meant lots of engine braking but regen on a Tesla is more and so the lights should come on.
It seems the situation is worst when slowing down and starting regen too soon, then coming off of it as you realize you're stopping too soon... and back on it and off.... which is expounded by people who aren't using regen around you that are on different braking rhythms. This is different from brake lights when you use the brake pedal because it is easier to modulate brake pressure while maintaining some pressure to keep the lights on. Also, you are more likely to find yourself needing more brakes than less in an ICE if you just wait long enough (and with the engine idling, that helps too).
I think you are one of 5 people on the planet that think that way. No one else thinks to maintain "some pressure to keep the lights on." They jump on and off the brakes as they deem necessary with no regard for what the lights are doing.

At the end of the day (and we've talked about this in numerous threads here), I think we need a slightly different system for brake lights and I don't think Tesla can solve it on their own. Some have proposed amber lights for regen and red for friction brakes. I have video of a bust (one of the infamous "tech"buses) that is set up this way. Or we could have a system of multiple levels of brake light intensity based on how quickly the car is slowing. The first one Tesla could do on their own and hope others figure it out and adopt it, like the aforementioned bus. The second one would require a dialog with other manufacturers, governments, drivers, etc to agree upon a different system. I think Tesla has already bitten off more than they can chew without trying to rewrite long-established driving norms. I'm glad they erred on the side of safety
 
In many countries it is required by law that regenerative braking activates the brake lights. It makes sense as it slows down the car like a normal brake. The fact that a friction brake can slow the car down even faster is irrelevant. In the vast majority of cases people slow down their ICE vehicles at about the same rate as regen does.

BMW has developed an adaptive brake light that changes depending on the rate of deceleration. They even thought a step further and had a front camera interpret the brake lights of the car in front of you and avoid collisions. That was 15 years ago. It never made it because not all car manufacturers could ever agree on a standard.
 
exactly- go drive at night and turn on your rear camera... get on the hwy and watch when the tail lights illuminate. You can get a fair amount of regen going before they start to brighten.

Great suggestion.
I did this last night, and was surprised. The brake lights didn't come on as often as I thought...I was surprised in a good way since I thought my brake lights were constantly going on-off-on-off whenever I slowed down. They did come on when I decelerated a lot.
 
I think you are one of 5 people on the planet that think that way. No one else thinks to maintain "some pressure to keep the lights on." They jump on and off the brakes as they deem necessary with no regard for what the lights are doing.

I have actually taken to doing this. I wonder who the other 4 are :smile:

I keep a light pressure on the brake pedal when coming to a stop to keep the brake lights on. I've noticed that the re-gen activated lights go out as I coast down, and am concerned that the guy barrelling up behind me may not realize I'm coming to a stop at a red light or such. He might suspect I've started to accelerate again when the lights go out. I don't even like sitting at a traffic light without my foot on the brake because I would be concerned someone coming up behind and not paying attention would not realize I'm stopped with no brake lights showing.
 
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... I don't even like sitting at a traffic light without my foot on the brake because I would be concerned someone coming up behind and not paying attention would not realize I'm stopped with no brake lights showing.
A number of years ago I got bumped from behind because I let my foot off the brake when I expected a light to change. It did not and I didn't move, but the other guy did. So your concerns are well founded. (I was an old car I didn't care about, very small dent, and the other driver apologized so I told him to forget about it.)
 
Reading through this thread, all seem to have valid points. When I first drove my MS home from NYC on the LIE, I had no idea that the break lights went on and kept wondering what the drivers behind me were thinking. So even in my first ride, I did try to regulate my deceleration with the pedal. Again, without knowing about the break light coming on, my thought was to drive the MS similar to the manual transmission cars that I had. I was always big on not using too much of the break and downshifted accordingly. Now that I know about the regen-break light, I actually feel more comfortable that it is there. The only spot where i feel like the back to the manual transmission days is after you decelerate below the regen-break light activation, as coming up to a stop sign or red light. With all valid points, I do feel that something is better than nothing, just to alert the driver behind that a change in speed and/or activity is happening.
 
I don't even like sitting at a traffic light without my foot on the brake because I would be concerned someone coming up behind and not paying attention would not realize I'm stopped with no brake lights showing.

Given the differences in brake light level between cars (some cars' normal lights are brighter than other cars' brake lights), I'm not sure that this is valid.
 
Given the differences in brake light level between cars (some cars' normal lights are brighter than other cars' brake lights), I'm not sure that this is valid.

Well, there are certainly some crappy brake lights out there, but again, I'd rather have brake lights on as opposed to off when I'm stopped or stopping. The Model S has pretty decent brake lights when they're on, and part of my concern is someone seeing the brake lights go out and making the assumption that I'm not stopping any more.
 
Old thread, but worthwhile topic still.

I've owned manual transmission cars my whole life and don't drive them with excessive engine/gearing braking. That said, when driving my MS on the highway, my brake lights come on when I only partially let off the accelerator, and my speed reduces much less then it would if I'm driving a manual ICE - and that doesn't mean I'm downshifting, just letting off the gas. So requiring more "feathering" of the accelerator - an action that none of us needed to learn on the 99% of cars that we drove prior to our Teslas, seems technologically lazy on Teslas part. Also, there may be some of you who have exactly figured out how to avoid this every time, but for the vast majority of Tesla drivers I would bet there are plenty of times when you look like a nyc cab driver, brakes on, off, on, off. Rude to the person behind you, particularly when you're not stopping.

As for solutions, I don't think light intensity or different colors would ever pass regulations, but I think Tesla would do well with a "Medium" setting on regen that allows for drivers, particularly on the highway, to very briefly left off the accelerator (as you might when you've passed someone and are now lane shifting allowing others to pass you) and delay brake lights until you've stayed off the accelerator for, say, 1 second. You know, like when you actually intend to slow down or brake or stop. My $.02.

European drivers appear to bring this topic up quite a bit throughout the forums. I assume that is because manual transmissions are more common and they are generally better drivers then our lousy drivers in the US.
 
my brake lights come on when I only partially let off the accelerator, and my speed reduces much less then it would if I'm driving a manual IC

That's not my experience. I have to let off to more than 50% regen for brake lights to come on, and that's pretty much the same as the max slow down I would get in Manual ICE on engine braking alone (short of just jamming it into a lower gear and lifting my foot straight off the clutch with no throttle!).

My understanding is that there is a regulatory requirement for the amount of deceleration that mandates brake lights coming on.
 
I hate how regen turns on the brake lights. I bet it makes everyone behind me think I'm brake checking them. Very dangerous IMO. Brake lights should come on only when I touch the brake. Regen feels to me equivalent to downshifting in a car to slow down, but brake lights do not engage when downshifting....and they should not engage for regen braking either. I want an option to turn this off please!!

The correct way of lighting Brake Lights on Regen would be to detect if your car is actually slowing down a) relative to the traffic in front of you (i.e., your followers should be warned your speed is getting lower) OR b) both you and the traffic in front of you is slowing down
(i.e., your followers should be warned your speed is getting lower).

This would allow overtaking cars and using regen to get "back in line" safely without flashing brake lights and scaring other people in line.

Yes, a quick solution to this would be simply to have an option to disable completely the flashing of break lights when break pedal is not pressed.

I wonder if that can be customized onto the car, connect break lights only to the break pedal?
 
Because so many drivers don't pay attention as they talk on their cellular phones, I use the flashers briefly on occasion. If a normal flow of 70 mph freeway traffic is suddenly stopping, I want the drivers way back who are still at full speed to notice the stoppage. Three quick flashes seems to work well without upsetting anyone. Preventing rear end crashes with long repair times resulting in insurance rate increases are worth the extra effort to flash those brake lights when necessary.
 
Because so many drivers don't pay attention as they talk on their cellular phones, I use the flashers briefly on occasion. If a normal flow of 70 mph freeway traffic is suddenly stopping, I want the drivers way back who are still at full speed to notice the stoppage. Three quick flashes seems to work well without upsetting anyone. Preventing rear end crashes with long repair times resulting in insurance rate increases are worth the extra effort to flash those brake lights when necessary.
I leave the flashers on about 5-6, until I'm sure the car immediately behind me at least, has seen and is slowing. I really don't want to test the safety of the S in a rear-ending stupid accident.

@yobigd20 : have to disagree with Tesla providing a "turn off regen brake light" option, it's a safety thing. At least we can now see when they're coming on! Remember the cries for that display change.

My brake lights don't come on very often on highway driving, because I give plenty of room for the car in front and then modulate speed with regen at a level where the lights aren't activated; it's far more relaxing than the jerky start/stop or speed/slow behaviour. I don't care if people "cut in line" in front -- driving is ultimately a team sport and we'll all get to our destinations within about 2 minutes of each other. I keep up with traffic flow so there's no reason (except stupidity) for drivers behind to be annoyed by the 7-10 car lengths in front.
 
This thread... sheesh. Talking about special blinking schemes, and different color lights, etc. believe it or not, to the rest of the world, a Tesla in front of them is just another car (no concept of "regen").

It's really simple, the purpose of brake lights are to indicate that the car is slowing at a rate that warrants attention by someone following the car. That's all it really means. The "problem" is that Tesla chose to make their throttle and brake be technically tied directly to, respectively, the drive system and the actual brakes.

My Ford Fusion Hybrid takes a much more user-friendly approach. When you lift off the gas, it "coasts", and does not enact regen. Then when you start to brake, it actually activates regen to slow the car until you press beyond a certain point which starts to engage the hydraulic system.

As others have pointed out, and what I have learned to do, is drive the Tesla as to mimick that behavior, that is, by keeping the throttle slightly pressed for "coasting" when that is what I want to do, and lifting completely for "braking", and the use the brake pedal for heavier braking.

I do wish Tesla would have done it the way Ford did it, it is for more simple.
 
I do not think the hybrid car method is proper. I think Tesla got it right and while this 'discussion' has been happening for years now, I still think Tesla got it right.
It's really simple, the purpose of brake lights are to indicate that the car is slowing at a rate that warrants attention by someone following the car. That's all it really means.
Exactly that. Strong regen slows the car quite a bit, therefore people should be notified.
 
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If the purpose of brake lights is to indicate the car is slowing, then why do you think the hybrid car method is not proper? No brake lights until you press the brake. Only difference is they connected regen to the brake pedal vs. releasing the throttle.

So both do the "right" thing in showing brake lights when the car slowed, but the hybrid is closer to what 95% of the population expects from a user interface perspective.

I do not think the hybrid car method is proper.