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Additional safety tip for Model S. (One Free Model S for me maybe).

As one of Tesla enthusiasts. Just want to mentioned you guys did awesome job on delivering all Model S on the street.

I live in Folsom, California and often drive to SF bay-area. and almost everytime I see at least one Model S on the way there. Btw, for those who didnt know, Folsom has the privilege of having Tesla Super Charge, so you guys should stop by to the city.

And there is one time I just purposely tail-gate (from a distance) on one of the car. The car looks Awesome, as I drove along, it hit me that occasionally I have to hit break quite often, as the Model S in front of me appears of just slowing-down (without Break-light turn-on). As I mentioned, since I am an enthusiast, I realized that this must be one of the feature of Tesla rapid-slows down and regenerate the power back to the battery feature. In normal gas-car like I drive (Lexus rx330), it would need to press on
the Break-paddle, even after you release the gas-paddle, to slow the car down.

Not knowing that the Model S in front of me is actually slowing down rapidly, makes the regular driver (like my self) think that the traffic still looks OK. This event would trigger a wrong assumption and causing real crash/accident just because the Model S with rapid-slow-down rate == gas-powered with small break.

So the above is the problem, but I do think have a solution for it:
It maybe worth to do software-update on the Model-S, so that when the rapid-slows down/regenerate power happens, a small dimmed-breaklight at the rear turn on a bit, indicating the Model S is really slowing down. and when the driver do press the break-pedal, it can then light up all the break-light. I believe this would make Model S even safer and less got Hit (to be exact) from behind.

To all Model S enthusiast, let me know how you feel about the problem and solution.

and perhaps if Model S engineer/executive liked the idea, I could get one free model s for it? =)


The software for the car already triggers the break lights when doing regenerative breaking, so you shouldn't be seeing this issue at all.

Good Tip.
Hope someone at T is reading!

JamesIwan, andrigtmiller is correct, the car already does this, but only when you hit a certain threshold of regenerative braking. It will slow some without triggering it. It sounds like you were maybe just following too close. Of course, I've not followed a MS myself, so perhaps the current mechanism is inadequate...

I think the OP is suggesting a tiered brake light system where the lights come on at a reduced brightness when regen kicks in and then full bright brake light when brakes touched. I think it's an interesting idea. Not sure what the safety laws have to say about it however.

Someone posted about a road-rage incident when they passed a car and then let off on the accelerator once ahead. The car that got passed became angry because he saw a Tesla pass him and then assumed the Tesla was braking right in front of him. When in reality the Tesla was simply allowing his speed to fall back to a normal level. I'm concerned about this too.

Perhaps there's a lesson...
1) Don't tailgate
2) Look at traffic ahead of just the car in front of you to best gauge traffic flow

I should probably head #1 myself :)

I had a 2004 BMW 5-Series and it featured different levels of break lighting depending on braking. If I used normal pressure, the normal break lights would come one, as one would expect. If it was a sudden stop, an additional break light would light.

Regular ICE cars can slow down quite rapidly without turning on the brake lights -- any manual transmission car can slow much more quickly than the Model S even at 60kW regen.

The Model S turns the brake lights on based on how fast the car is slowing down using an accelerometer. You can argue for changing the threshold of it, but the basic idea is already implemented.

Agree with @JZ13, I know that many reviews says that you will rarely use the break on driving Model S. It just much safer if it shows level of breaking-light to indicate that Model S is decelerating at equal rate at normal break. start with reduced-brightness and increase them as the car getting even slower might work.

Also, just to be clear, I didnt tail-gate at the close-distance, maybe I should say "follow" instead of tail-gate. :).

type 100 times: brake lights

If we really want to improve safety, I think the best improvement would be to attract the notice of the driver behind if the car in front is decelerating rapidly. If you are driving behind someone and they break normally, there is not much you need to do about it. You judge the distance to that car and slow to keep it reasonable for the given speed. If break lights were that critical in these situations, you would be hearing all kinds of complaints about manual transmission cars slowing down without break lights.

The situation where break lights could really help is in a sudden stop. If the system detected deceleration above a certain threshold and flashed the break lights rapidly, the driver behind would notice and would have the chance to slam on the breaks before hitting the car in front. Since the flashing would only occur in a sudden stop, the fatigue that normally occurs when someone sees break lights coming on would not occur.

At night the tail lights are on already, so a partial decelerate with reduced-brightness, would break the brake light idea.

That is 1 brake light for Brian H.

Give us a brake Brian!


Good idea on the triple rapid flash on a hard decelerate.

I still like the way non-US cars use amber for the turn signals.

As noted above-- the MS brake lights come on at deceleration. Shouldn't be an issue. If you have some idiot tailgating you and have to panic stop you are screwed. There would be no brake light array that prevents driver error (texting, tailgating, distracted) for rear collisions to your vehicle.

Years ago, before the CHMBL (Center High Mounted Brake Light) became standard on American cars (1986), there was an aftermarket brake light available that would flash slowly on deceleration and would flash faster as the deceleration increased. The faster the deceleration, the faster the accessory brake light would flash. When the car was completely stopped, the brake light went solid red. The standard tail and brake lights worked normally. It was a great idea...saw it on a few cars in the early to mid 1980's.

Nice reference @sagebrushnw. but instead of flashing, it will be great for just the brightness/dimming of the break light that could tell how fast the deceleration rate is. many have been saying that the system is actually already there. but perhaps its worth to ask Tesla to mention how the break light-system work with rapid-deceleration in the Model S spec website, to educate all the model s enthusiast here.

tjyudman +1

I think the OP points out two series problem:


Both are easily solved if he so chooses!

I just did a little research and found some information about the Cyberlite system that I was referring to above. It was developed by Dr. John Voevodsky of Portola Valley, CA and was approved for sale in California in October of 1974.

Great information @sagebrushnw ! Like it.

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