Brake lights seem to be an issue in some Tesla accidents. The Tesla is rear ended.
Regenerative braking in my Model Y works very similarly to the way I used to brake in my other vehicles - with one huge exception: no brake lights going on. (My son almost drove into a car that was parked 2 feet from the curb in an English town. I was being the typical American dad-passenger and watching and it fooled me too.
Something moving directly towards or away from you is less perceivable than if it has any side movement. All predators on their final rush go straight in. Depth perception moving straight towards or away from is minimized, because it is solely based on change of size. That panic hitting the brakes is probably when we reach a mathematical point where the vehicle in front of us begins to rapidly change size.
So Tip 1. To some degree light up the brake lights for regenerative braking. When does regenerative braking slow the Tesla enough to be similar to braking but with no brake lights? (In my Prius V going down mountain inclines when I'm in B (braking Drive mode) I can tell that the drivers behind me are having to (somewhat) emergency brake.
Tip 2. Screen display. Indicate when the brake lights go on. I want to know. My standard safety procedure for exiting a freeway if the cars ahead are stopped and I'm the last one is to tap my brake pedal to flash my brake lights. An important part of this is to be irregular so I'm not misperceived as using a turn signal.
On my screen I would like to know what information I'm sending to other vehicles.
Tip 3. Varying brake lights. Tesla could when the vehicle is stopped in situations like #2 above create a specific irregular brake light flash feature to automatically do this (when the situation is such that a driver behind might misperceive the Tesla as moving). I don't know how the NTSB Laws and Regs work on this, but it's probably not disallowed. And with some road miles and a reduction in rear end collisions could become a standard feature on new cars and a SOP for intelligent drivers of all vehicles.
Tip 4. Brake light intensity. When brake lights go on, they are perceived by following drivers as 'brake lights' If in a situation where a slow to stop turns into an emergency stop, if the brake light intensity could increase this would further warn the approaching drivers of the increased urgency.
Tip 5. Always Leave an Out, When I drive I always try to pay attention around me so in some emergency situation I know that I can immediately change lanes. (I did this one time, when I was very tired. The car directly to my left suddenly moved 3-4 lanes to the right. I automatically went with him keeping about 18" away from him. When he finally realized I was there, he immediately changed lanes to the left - and I immediately followed him for about half a lane, keeping the same 18". So all this was automatic.) I suspect that Tesla Self Driving is already doing something like this.
Tip 6. Take the Out For Others. As part of my always leaving an Out, in heavy traffic I think of this Out to my left or right as an emergency exit. In the past 40 years I've probably helped avoid more than a couple of multiple car rear enders. All the cars ahead slam on their brakes, I hit mine too, but then I pull into the space I've always looked for as SOP. More than a couple of times, screeching rubber, I'm to the left or right and directly next to me, in the space my car was is another car, its driver eye to eye with me. A smile and a shrug, he didn't hit me, the guy behind him didn't hit him.
Tip7. Look through to the cars ahead. I'll drive closer to the car directly infront of me in heavier traffic if I can look through his windows and see the brake lights on the car in front of him. In fact I routinely try to monitor the car in front of the car directly in front of me. It gives me a better safety margin.
I've been driving for 45 years, these are practices I've used for most of that time or based on that experience. If they seem lacking or in error, it's probably the way I've explained them. Hope this helps.