Uber has applied for a patent to spot would-be passengers who are drunk. Even if granted and used, the patent wouldn’t necessarily mean such passengers would be denied access to the service.

The patent – filed in 2016 but only just made public – uses the euphemism “predicting user state” but the detail and context makes clear it’s talking about customers who are drunk, on drugs or otherwise impaired.

The technology would involve checking one or more characteristics including how quickly (or slowly) the user is walking, how quickly and how accurately they are typing date into a phone, the way they interact with interfaces (such as buttons and maps on the Uber app), and the angle at which they are holding the device.

It wouldn’t just be the presence and levels of impairment indicators that would be taken into consideration, but how they compared with the user’s previous readings. This would also take into account the readings from any previous ride where a driver reported the user as impaired.

The patent notes it isn’t simply a case of flagging a passenger as impaired and letting drivers know so they can make an informed decision about refusing to take a fare. It could also mean assigning a driver who is more experienced at dealing with drunk passengers.

The assigned pick-up point could be affected as well. Rather then the nearest standard pick-up point, the passenger could be directed to somewhere that’s better lit, sent via a longer but safer route (such as avoiding crossing busy roads), or delaying the driver’s arrival so the passenger has longer to reach the pick-up point before the virtual meter starts running.

Uber also says drunk passengers could be blocked from using carpool services where they ride alongside other passengers they don’t know.