For a high tech vehicle with so many safety features built in, I don't understand why an automatic collision avoidance system didn't override the autopilot syst

For a high tech vehicle with so many safety features built in, I don't understand why an automatic collision avoidance system didn't override the autopilot system and start braking well ahead of this high speed impact. Maybe this model doesn't have such a system, or the traffic conditions changed so rapidly there was no time left to brake?