When designing a smartwatch app for Uber, the focus should be on simplicity, speed, and convenience, while also considering the constraints of a smartwatch interface. The main user interface should display a map showing the user's current location along with nearby available Uber vehicles. By simply tapping on the watch, users should be able to request a ride. Additionally, incorporating predefined voice commands for common destinations like 'home' or 'nearest airport' will further streamline the process. It’s also important to provide ride status notifications directly on the smartwatch. Users would benefit from knowing when their vehicle has arrived, the estimated time of arrival at their destination, and any route changes caused by traffic or congestion. Finally, to enhance safety, the app could include an SOS button or a quick dial feature for local authorities. This would allow users to discreetly alert someone in case of an emergency during their ride.