Uber now uses your smartphone (and your driver's) to detect car accidents.

Last year, Uber announced a new feature called "RideCheck" that uses GPS, accelerometer, gyroscope and other sensors inside a smartphone for detect irregularities in the journey, such as a vehicle accident or a long, unexpected stop. After a year of testing and refinement, RideCheck is now online in the US, and other countries will follow soon, the company said.

The system alerts runners and drivers when something extraordinary is detected. A notification will appear asking if all is well, which leads to a list of possible answers, including the possibility of calling the authorities at 911 or the Uber security hotline. If Uber checks for an accident, the rider will be asked to call 911. Uber's security team can also reach out to make sure the rider is safe when the feature is activated.

This feature does not require any new permissions because it is tied to the driver's smartphone rather than the drivers. The Uber app is used more by drivers than by drivers, who usually keep it in the background during journeys.

To avoid any false positives, like a dropped phone, Uber uses machine learning to take into account several factors besides the input of the phone's sensors. Drivers and drivers may also agree in response to the initial notification, which improves the RideCheck system over time.

Admittedly, the use of smartphones to detect road accidents and react to these accidents is not a new technology. Other companies and startups, such as Zendrive, have been working for a number of years on similar accident detection technology. Other systems, such as GM's OnStar, use sensors built into the vehicle itself to detect accidents and automatically alert authorities.