Regen and Brake Lights - Highway Issue

[kendallpb]

If like Knox you have the habit of putting you foot over the brake as a safety precaution (I do) then you may indeed put your brake lights on in the process which would make the next safety conscious driver behind you do the same and so on and so on. This is the reason for traffic slow ups.

...and it's a retraining issue, not a brake light issue. Moving your foot to the brake pedal in an ICE, what folks are used to, doesn't do the same thing in a Model S--it slows you down, sometimes significantly. The problem's not the light; the problem is effectively braking, sometimes sharply, when not intending to. IMHO!

This thread might brake the record for have the most break msipelllings.

Heh. Now I'm wondering how to spell break, brake, br8k, brachiate....

 

[BobHodgen]

I've always subscribed to this rule: Whats Not Important - YouTube

 

[Brass Guy]

...then let the regen bring your speed back to cruising velocity, but to the driver you passed, this move looks highly aggressive...

You want to slow aggressively but not appear so. If you're using full regen after passing, you are driving aggressively.

...introduce something like "Medium" Regenerative Braking setting without the need of brake light and still have some useful regen ?

No. The MS has the low regen for people that don't care to get used to the regen behavior. That's fine, to each their own preference.

If you want regen but you don't want the brake lights on, don't regen all the way. Learn to be smoother with the accelerator pedal. People who drive should learn how to drive. Sorry to sound aggressive myself, but it's starting to bother me how many people seem to think slowing down with regen is all or nothing, or that the car should decide how much you want to slow in a given circumstance, or are just too lazy to use the right foot to adjust.

Tesla did an amazing job with the accelerator pedal control. If you're using full regen on the highway, either you weren't looking ahead, something happened abruptly, or you're driving aggressively; and your brake lights should come on because you are slowing down.

 

[wycolo]

Several mentions of 'rapid downshifting' of manual trans cars. Properly done this involves putting brake on throughout, using the 'heel and toe" maneuver, in order to maximize braking and also to equalize stress among systems. In a long race success can depend upon all systems surviving. If you leave out the 'toe' part, your implementation is just half-fast. :smile:
--

 

[Gizmotoy]

You want to slow aggressively but not appear so. If you're using full regen after passing, you are driving aggressively.

That is a silly assertion. The proper technique for passing is to speed up to reduce your amount of time in the passing lane. Once you get back over into the cruising lane, you coast back down to speed. That's not aggressive, that's correct.

If the emphasis here was on "full," then it should be noted the brake light comes on well before you hit full regen. Indeed, at highway speeds it doesn't take much.

 

[brianman]

If you're using full regen on the highway, either you weren't looking ahead, something happened abruptly, or you're driving aggressively; and your brake lights should come on because you are slowing down.

Just an observation:
When the speed limit changes by 10mph (you enter a construction area for example), if you dip the CC by 5mph twice quickly you can sometimes induce full regen.

 

[AmpedRealtor]

My main concern is that some driver get very upset when overtake by others, and very very upset if you brake after overtaking him; and that would have consequence.

Will it be useful Tesla could introduce something like "Medium" Regenerative Braking setting without the need of brake light and still have some useful regen ?

Let's put it this way. If you were driving any other car with automatic transmission, the rate of deceleration you experienced and needed in your Model S as described above would have required use of the brakes in another car. As such, the Model S is behaving appropriately by alerting the car behind you of a rapid deceleration. If you were driving a stick shift and downshifted to achieve the same rate of deceleration, you are a potential hazard because the car behind you has no visual cue - other than your car getting big really fast - that you are decelerating.

 

[Brass Guy]

I seem to recall driving an automatic that allowed the engine to idle when letting off the gas pedal, even when in overdrive. (I remember being frustrated that every time I went back to the gas pedal, no matter how gently, the transmission would go into a lower gear before engaging overdrive again.) Definitely need brakes to match MS regen deceleration in most ICE vehicles. That is unless you have a really bad cd or low tire pressure.

 

[tchaimd]

I can't stand the accelerometer driven brake lights. I'm used to manual transmission cars and downshifting. The most common scenario for me where this is an issue is passing. When you pass someone, you use a bit of that Tesla torque in order to get past quickly and safely, then let the regen bring your speed back to cruising velocity, but to the driver you passed, this move looks highly aggressive since the brake lights come on as soon as you are back in front of them. If there were an option, I'd turn this off and use my brake pedal to notify other drivers of when I'm *actually* stopping.

I agree with this post. I certainly don't want the brake lights to come on after passing someone on the highway and returning to the right lane. I'm used to briefly coasting upon return (with my foot over the brake pedal just in case, especially if there is a car somewhat close in front of me). Therefore, as it currently stands, I wouldn't be able to do that, since I would have to still have my foot over the go pedal to slowly lift off to prevent the regen-induced brake light activation.

It would also be nice to have an auto regen setting at "low" (or none) at highway speeds (>55 mph) and "standard" at city-driving speeds.

 

[JohnQ]

After a year I haven't had any issues with passing, regen or covering the brake. And I prefer to cruise at 80mph when not conserving range. Keeping your foot on the accelerator is covering the brake. I've found that there's sufficient deceleration to handle normal maneuvers without the brake lights illuminating. And I have much finer control. If I need to be more aggressive, there's a significant deceleration when you lift the pedal that's just like an initial press of the brake pedal. If you need more, the brake is there waiting for you.

In my opinion, Tesla got this just right.

 

[AmpedRealtor]

The solution is simple. Just don't lift your foot completely off the accelerator. If you don't want a sudden deceleration, then just lightly let up on the accelerator. If you want rapid deceleration without brake lights, well that's a hazard and you should not be able to do that. Doing so in a stick shift is also a hazard. Model S is a good citizen in this regard, preventing you from doing such things despite yourselves.

 

[SeminoleFSU]

After a year I haven't had any issues with passing, regen or covering the brake. And I prefer to cruise at 80mph when not conserving range. Keeping your foot on the accelerator is covering the brake. I've found that there's sufficient deceleration to handle normal maneuvers without the brake lights illuminating. And I have much finer control. If I need to be more aggressive, there's a significant deceleration when you lift the pedal that's just like an initial press of the brake pedal. If you need more, the brake is there waiting for you.

In my opinion, Tesla got this just right.

The solution is simple. Just don't lift your foot completely off the accelerator. If you don't want a sudden deceleration, then just lightly let up on the accelerator. If you want rapid deceleration without brake lights, well that's a hazard and you should not be able to do that. Doing so in a stick shift is also a hazard. Model S is a good citizen in this regard, preventing you from doing such things despite yourselves.

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.

 

[Jaff]

+1...all it takes is a little experience driving the car to control this issue.

I also think Tesla got this right...remember, they must err on the side of caution & safety.

After a year I haven't had any issues with passing, regen or covering the brake. And I prefer to cruise at 80mph when not conserving range. Keeping your foot on the accelerator is covering the brake. I've found that there's sufficient deceleration to handle normal maneuvers without the brake lights illuminating. And I have much finer control. If I need to be more aggressive, there's a significant deceleration when you lift the pedal that's just like an initial press of the brake pedal. If you need more, the brake is there waiting for you.

In my opinion, Tesla got this just right.

 

[mibaro2]

I like the way the lights work now. One scenario I can think of is if someone (Tesla or ICE) presses their brake very lightly. So they are hardly slowing down at all, but their full brake lights would go on. If I release the accelerator and regen, slowing down faster than the person who has slight pressure applied to their brake....it would be confusing for any other driver to know which car is slowing down more.
As others have said here..if I see brake lights go on in the car in front of me, I prepare for the worst (that they are screaching to a halt) , and hope for the best (that they are just slowing down).

 

[mknox]

The solution is simple. Just don't lift your foot completely off the accelerator.

Not always as easily done as said. In my neck of the woods, I'm always contending with cars cutting me off, swerving towards me only to correct at the last second and so forth. This all the time with cars following 6" behind me. When that happens, it's instinctive to let go of the accelerator and "cover" the brake in case you have to stop quick, which results in a lot of brake light flashing. In normal driving with little traffic, it's easy to modulate the accelerator, but in over a year, I have not been able to carefully modulate the gas when cars abruptly cut in front or swerve towards me. In a gas car, you coast modestly for a second or two then resume.

 

[Kipernicus]

I was behind a Model S driving down a hill the other day, and its brake lights kept going on and off, even though traffic was moving at a steady speed. I used the info screen to see if my car was doing the same, but it was not. I guess it was just one of those people that treats the accelerator as a binary input.

I was behind one of those the other day. Brake lights on off on off on off on off.
Rather annoying.

It's too bad Tesla disabled the active car image in the info screen.

 

[Amped-Up]

Been wondering about the brake lights since getting the car a couple months ago. Good points raised above and make a lot of sense about driving smoothly and anticipating. However as a newbie, I wouldn't mind a small light on the dash that lights when the brake lights go on. It would be switchable so after you get the hang of it, you can turn it off. I bet it could be done with a software update. But until then, if ever, I'm going to try the night driving with the camera on to see whent he lights go on. Thanks for that suggestion.

 

[strider]

I was behind one of those the other day. Brake lights on off on off on off on off.
Rather annoying.

It's too bad Tesla disabled the active car image in the info screen.

I drive behind ICE's that do the same thing - being smooth w/ the throttle and brakes are a universal skill to be learned and not unique to EV's. Please do not add more distractions to the car - the LAST thing I want is someone watching the screen instead of paying attention to the road and crashing their car. Just drive the freaking thing. Go to a driving school if you want to learn how to be smooth.

 

[ThosEM]

Remind me why are we are trying to be polite to tailgaters? Personally, I would like to have the brake lights come on and better yet, flash continuously without me having to take my foot off the accelerator, or touch the brake, when I'm being tailgated. Seems like a great use for the parking sensors ;=)

But all seriousness aside, I find that driving a car with no regen is really quite disturbing now that I'm accustomed to it. My BMW 328i seems like it freewheels when I take my foot off the accelerator, even if I downshift the 6 speed manual. Why am I having to use the brakes all the time!? It has me wondering if BMW has somehow used variable valve timing to somehow remove any throttle drag from the engine at all speeds! But I suppose it's just the contrast making it seem that way.

Also, I very much like the authority with which cruise control works by having regen available when going down long hills. Our Lexus RX400h had very poor control allowing it to coast far above the speed setting on downhill stretches. If one tried to put it in "B" mode, the cruise control was disabled. I agree that Tesla has done this right.

 

[Kraken]

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).

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.

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).