Emergency braking is designed to lessen the impact, not prevent crash. See manual. This is mostly for avoiding crashes into a car that suddenly stops in front o

Emergency braking is designed to lessen the impact, not prevent crash. See manual. This is mostly for avoiding crashes into a car that suddenly stops in front of you, I.e. in lower speed city traffic and jams. For this, detection within a few meters is all you need - ultrasound sensors might do. If the velocity delta is 120km/h, you’re not going to meaningfully slow down when already this close.