Automatic crash detection used to require a dedicated device. Today the phone in your pocket - or the car in your driveway - can detect a severe collision and call for help when you cannot. Here is how the major options compare, and how to turn each one on.
How crash detection works
All of these systems combine three signals: sudden deceleration measured by the accelerometer, a sharp change in direction or rotation, and (in cars) airbag deployment or impact sensors. When the pattern matches a severe crash, the system starts a countdown - a loud alarm with a few seconds to cancel - then places an automated call to emergency services with your location.
Side-by-side comparison
| System | How it runs | Cost | Notable limits |
|---|---|---|---|
| iPhone Crash Detection | Built into iPhone 14 and later | Free (cell service needed for the call) | Can false-trigger on hard drops or roller coasters; requires the phone to be with you |
| Google Pixel Crash Detection | Built into Pixel phones (Personal Safety app) | Free | Availability varies by country and language; needs location permission |
| Life360 | App on iOS and Android | Free tier; crash detection on paid plans | App must be running with permissions granted; family gets notified, dispatch handled through its service |
| OnStar Automatic Crash Response | Built into GM vehicles | Subscription after trial | Works even without your phone, but only in equipped vehicles |
| Apple Watch Fall/Crash features | Watch Series 8 and later (crash), Series 4+ (fall) | Free | Companion to the phone, not a replacement; watch must be worn |
How to turn crash detection on
- iPhone: Settings → Emergency SOS → verify Call After Severe Crash is on. Keep Location Services enabled.
- Pixel: Personal Safety app → Features → Car crash detection → turn on.
- Life360: install the app, join your family circle, and enable Crash Detection on a paid plan.
- OnStar: press the blue button to confirm your vehicle's service plan is active.
What these systems cannot do
- They detect severe crashes. Low-speed impacts may not trigger anything.
- They need power and signal. A dead phone battery or a dead zone means no call.
- False alarms happen. Know how to cancel the countdown so you do not tie up dispatchers.
- None of them replace calling 911 yourself when you are able.
Our recommendation
Turn on the free built-in feature on every family phone today - it costs nothing and covers the driver who forgot to charge the tracker. Then decide whether a paid service adds value for your situation: a GM owner may already have OnStar, and parents of teen drivers often want Life360's location sharing anyway. For seniors, compare dedicated medical alert systems with fall detection, which are designed around a different problem.