Apple Inc. AAPL -1.82% plans next year to roll out a product feature called “crash detection” for iPhones and Apple Watches, according to documents reviewed by The Wall Street Journal and people familiar with the feature.

Crash detection uses data from sensors built into Apple devices including the accelerometer to detect car accidents as they occur, for instance by measuring a sudden spike in gravity, or “g,” forces on impact.

The feature would mark the latest move by Apple and its competitors to use motion-sensor technology to build safety functions into their devices. Apple introduced a fall-detection feature in its smartwatch several years ago that senses when wearers have taken a hard fall and dials 911 if they don’t respond to a notification asking if they are OK. The company this year added a feature to the newest version of its iPhone operating system that assesses the walking steadiness of users.