[kileywm]

While brake lights are a fine and necessary signal, I find myself wishing that cars would display speed & acceleration deltas compared to the vehicle in front. Brake lights do not convey how much deceleration is occurring, so it's not immediately obvious how much time there is to impact.

As an example, I see lots of drivers do minor braking on US highways, where their small braking corrections will cause their tail lights to flash for a brief moment. These minor corrections become noise that drowns out the signal of significant, safety-related braking. If my vehicle could warn me that their rate of deceleration puts our vehicles on a collision course... now that would be very useful.

[archi42]

Some do: In ACC mode my 2013 Volvo uses radar to "lock" on the car in front of me. If it is slower than the ACC set point, its speed is indicated in the instrument panel.

It looks like this: https://www.motoreport.de/wp-content/uploads/2014/01/IMG_296... Set point is 110 km/h (green marker), the car in front is going 80 km/h (solid white line indicates the speed difference). The small red triangle indicates the speed limit of 80 km/h. Obviously the ACC is also cruising at 80 km/h, so most indicators are focused there.

And you're right, even with the limited form (single car in front of me on the same lane, data only shown if slower) this is amazing.