https://thenextweb.com/apps/2018/05/29/uber-adds-a-911-panic-button-to-its-us-app/

Uber today pushed out a special option within its app that allows US users to contact emergency dispatchers immediately, potentially sharing their location as well.

According to The Verge, the “panic button” has been added to the safety center menu on the app’s main page, and is labelled: “911 assistance.” After confirming you intended to do that (presumably to cut down on pocket dials), the app will link you with emergency dispatchers. It was tested earlier in India and is now rolling out in the US.