Problematic transportation outfit Uber is thinking about a way to use your phone to determine if you've been drinking. A patent application was uncovered by CNN, entitled "Predicting user state using machine learning," which outlines the general idea. Essentially, by watching how you behave day-to-day, the system can pick up when your behavior is normal (for you) or abnormal. That could be, for instance, how you use your phone, the angle at which you hold it, and even how you're walking.
Obviously there are some common sense elements to this, too, especially if you're requesting a ride in the small hours from a notorious night spot. The thinking is that drivers will be fed this information ahead of you boarding the vehicle to better prepare them for what's coming. A cynical reading of the plans could mean that drivers choose not to pick up a ride from a drunk passenger to avoid trouble. That would likely mean they're left fending for themselves or, worse still, choose to drive themselves instead.
Of course, patent applications are mostly the province of companies wealthy enough to devote such time to dreaming up new ideas. Wacky concepts and ideas are patented all the time in the hope that, in years to come, they prove to be both useful and profitable. There's no indication that this system is going to pop up in Uber's customer-facing app in the near future, although it certainly could do.