That’s why we’ve been running a pilot program to verify feedback using smartphone technology. Gyrometers in phones can measure small movements, while GPS and accelerometers show how often a vehicle starts and stops, as well as its overall speed.  If a rider complains that a driver accelerated too fast and broke too hard, we can review that trip using data. If the feedback is accurate, then we can get in touch with the driver. And if it’s not, we could use the information to make sure a driver’s rating isn’t affected. Over time, we hope to use technology to improve safety proactively.  For example, if gyrometer data shows that drivers are constantly moving their phones around, we can offer them mounts to fix the problem.

https://newsroom.uber.com/curb-your-enthusiasm/