Brake Light Hash Indicator




As most probably know, regenerative braking causes the brake lights to come on at varying points depending on speed.

I would like a little red hash mark on the edge of the dial to indicate the point when the brake lights will come on. At which point the hash should glow a brighter red while brake lights are on.

The reason for this is I’m sure we are all unknowing “brake checking” people which can be a source of road rage. If I knew exactly when the brake lights would come on, I would only regen just shy of activating the brake lights in most cases.

This feature would help Model S drivers be more aware of what their car is saying to the drivers around them.


Moderator: We don’t believe this feature is technically possible. The brake lights come on at a specific g-force and have little to do with speed. While regeneration has some relation to g-force, it’s also not direct. For example, you could have a major regen going down a hill, yet insufficient g-forces to trigger the brake lights.


Closed as not possible.

Category: CY3XS Applies to:
     Created 3-Nov-2014


On my 2014 model S without autopilot, the icon for the car in the center display shows the brake lights glowing when they come on as a result of regen braking.

I think this has already been done and should be shown as a IMPLEMENTED request.

(although it would be nice if it was slightly more pronounced in the dash display).
    Created 4-May-2019
Yes, this request was basically satisfied with the release of auto pilot and the image of the car on the dash.   It is not an issue anymore.
    Created 1-Aug-2017
The brake lights come on in my cartoon car image on the dash.  Is that what is wanted?
    Created 1-Aug-2017
I'd like to see the reference that the brake lights are activated by g-force ... that seems like a distraction to me ... Conversely I did see a comment by Elon that "regenerative braking is braking, so the brake lights come on even when the brake pedal is not engaged" - that makes perfect sense to me and would be fully compliant with the intent of legislation requiring brake lights.

Honestly I totally agree with the request.  When driving an ICE car I know exactly when my brake lights come on: it's when I put my foot on the brake pedal.  I have no idea when the lights come on in my Tesla.  And no, doing trials at night looking for reflections in the glasses of the guy behind is not a good alternative.

Yes ... even if it is g-force driven it SHOULD engage the brake lights even when rolling downhill, because the effect of slowing the car is a function of the force vector on the car regardless of whether it's actually moving uphill or downhill.

The FUNCTION of a brake light is to inform the driver behind that we are slowing down MORE QUICKLY THAN HE WILL if he merely releases his gas pedal.  And - frankly - if our lights are coming on and off because we have no idea, it's because he needs to know we're cluelessly slowing down quicker than a coasting car.

The point about being considerate to the car behind is very valid.  If we don't know, we can't control whether we're flashing him and may inadvertently cause him avoidable anxiety.  Knowing the state of our brake lights helps us be considerate citizens ... and - sorry - I don't accept it's hard to implement: it just needs a software update and a bit of graphic design on the dash to do it.

Just as important as the beautifully designed and implemented blind-sport warning, and no harder to do.
    Created 4-Jun-2015
Actually some of the displays already do this. If you have the charging screen up while driving, it will show when the brake lights come on. It is electronic, not based on regen, g-force, etc. Put that indicator on the driver's screen.
    Created 3-Jun-2015
Once you get used to the car, you know when it kicks in.. drive around a little at night and get a feel for it.. it becomes 2nd nature and won't be necessary on the dash
    Created 2-Dec-2014
The moderator hit this nail squarely on the head while also providing an example of why this is not a good idea as well as why it probably isn't possible.

I think this idea is a case of too much desire and not enough reason.
    Created 2-Dec-2014
This is imminently feasible. No different than telling you when headlights are on. Could cheat and mount a mirror on the back of the car reflecting brake light through side view mirror. (yes I also hillbillyed a way to hang my suit jacket/dry cleaning in the Tesla S).
    Created 2-Dec-2014
While I don't really care about the feature I disagree with the moderator that it would be difficult. Since you can already view the brake lights coming on by going to the correct screen on the center console, it would be easy to have it come up on the dash screen as well. I used the center screen to get an idea of when they came on until I got a comfortable feeling about it, but having it in my line of sight would have been safer.
    Created 2-Dec-2014
+1 for a visible indication that the brake lights are on.  After 42K miles, I would still like this feature.  Make it clearly visible, but not distracting, above the steering wheel.
    Created 1-Dec-2014
First, I should have said "Dash" Indicator.  I did mean hash, but hash could also be a pound sign to many people.   Dash would double for the location and the "-" mark.

Software is telling the brake lights when to come on.  The crazy math to figure out when to do this is a fixed formula.  Thus, could be used to mark the (floating) place on the dial this would happen.

Then when the brake lights are one, sensing the current would work but might be more expensive. Why not use the same (logically flipped)  software flag that turned the brakes on to also brighten the dash indicator?   Easy.
    Created 5-Nov-2014
I understand the moderator's comment about g-force.  But it should be quite simple for the car to indicate when the brake lights are activated. All it need to do is sense the current to the lights.
    Created 4-Nov-2014
It would be nice to have an indicator when the brake lights come on.   That way you could know what the guy behind you is seeing.   It seems like it should be feasible.
    Created 3-Nov-2014