I still think rear signaling could be improved dramatically by using a wide third-brake light to show the intensity of braking.

For example – I have seen some aftermarket turn signals which are bars the width of the vehicle, and show a “moving” signal starting in the center and then progressing towards the outer edge of the vehicle.

So now take that idea for brake. When you barely have your foot on the brake pedal, it would light a couple lights in the center of your brake signal. Press a little harder and now it’s lighting up 1/4 of the lights from the center towards the outside edge of the vehicle. And when you’re pressing the brake pedal to the floor, all of the lights are lit up from the center to the outside edges of the vehicle. The harder you press on the pedal, the more lights are illuminated.

Now you have an immediate indication of just how hard the person in front of you is braking. With the normal on/off brake signals, you don’t know what’s happening until moments later as you determine how fast you are approaching that car. They could be casually slowing, or they could be locking up their wheels for an accident in front of them.

Japan introduced brake lights that increase intensity based on how hard the driver was braking. 20+ years ago. They tested it in the US and drivers found it to be “confusing.”

I suspect because there’s no consistency in the brightness of vehicle lights. But that’s one of the reasons why I think an incremental light bar would be better, there’s no variation between vehicles. You could even make it more informative by flashing the whole bar when you first brake, so someone behind you can more easily see how much of the bar is being lit up.