If the crash detection feature detects a crash, it alerts users with a message and a sound.
The message can be ignored, but if it is not done so within 20 seconds, the system sends an automated message to the nearest emergency contact center.
Recently Apple released an update to iOS 16.1.2 that contains “Crash Detection optimizations.”
Apple has not explained what this means, although it probably aims to reduce unintentional activation in situations when there hasn’t actually been a car accident.