Any reason NOT to enable adaptive brake lights?
 

So I see that on my W211 I'm able to enable adaptive braking (blinking brake lights under hard braking). Any reason not to to this? Seems like it would be safer.

They probably are not legal in the US and most drivers probably would not know what they are. They may think you are turning and not bother to slow down. Blinking brake lights would not pass safety inspection in my state.

very common aftermarket on motorcycles. I dont see why it would be any different in any state to be illegal. Go for it.

I think it only engages on really sudden, hard braking....seems like it would obviously catch the attention of the (inattentive) driver behind me more than regular brake lights.

doing that to the high mounted third light would be good

I have seen many examples of the third brake light flashing. I think these are aftermarket add on devices, because I don't think any car out there has this behavior as stock.

The first kind (the most annoying) is the light flashes all the time the brakes are applied.
The second kind is 5 flashes then constant.

It is severely annoying to get behind someone who has this in traffic. I have seen this applied to some commercial vehicles as well.

I am not aware of any laws that prohibit the flashing brake lights but I am not a lawyer or traffic expert.

I thought I read that the newer MBs have the adaptive (on hard deceleration) brake light flashing enabled by default. I went looking around this morning but can't find the reference.

I think the adaptive brake lights are a very good idea. I'm going to look for the setting this afternoon on our W164. The kids drive this vehicle and they have a 2.5 hour trip that is all interstate between home and college.

With all the cheap micro electronic accelerometer technology out there I can't believe someone hasn't come up with an after market device to be retrofit instead of the "blink no matter what" devices.

Adaptive brake lights: Effective warning of rear-end collisions

If your vehicle supports the adaptive brake light feature, make sure to enable both the flashing brake light and hazard flasher. The adaptive
brake lights only function with panic braking from speeds over 30mph (the hazards only activate when stopped from speeds over 45mph).

Mercedes W212 adaptive brake lights demonstration

Shertex, what is your build date? My June 2005 E320's rear SAM does not have the adaptive brake light option to enable.

They're illegal and liability.

What statute or code?

LOL I'm not your lawyer. Ask the judge when you're found liable for modifying your brake lights after getting rear ended.

You're saying what the OP wants is illegal. I'm just asking what law says that. If there isn't a law prohibiting it, then it is legal.

SAE vehicle section J586, gives all requirements for a stop lamps on a motorized vehicles under 2032mm width. Must have a solid illumination with an intensity of 3 times that of the accompanying tail lamp bulb. The flashing stop lamp isn't directly illegal, if something has not been DOT/SAE approved - then by default it is illegal. This is all from quick google searching on SAE archival websites.

There are both state and federal laws that prohibit you from modifying your brake lights which include criminal penalties. Furthermore in a collision where you are rear ended the other party's insurance will look for any excuse to shift liability on to you. And we haven't even covered any civil damages. If you want to modify your brake lights go for it, just make sure you can afford a good lawyer.

I found the NRS pertaining to brake lights in Nevada. It doesn't call out DOT approval and doesn't specify whether the light needs to be continuous. However, the OP isn't in Nevada and should probably check his state laws.

I think there is a difference between your brake lights flashing all the time they are actuated and the way MB does it, where it is only on a drastic change in your speed to alert those behind you.

If I am coming up on suddenly stopped traffic on a rural interstate, I am tapping my brake pedal on and off rapidly to get people's attention behind me (obviously if I have enough time to do this without having to stop quickly myself). Are you telling me that it's illegal for me to blink my lights in an emergency situation to ensure the people behind me are aware?