Uber is going to start monitoring the behind-the-wheel habits of its drivers, including acceleration, braking, and turns, The Wall Street Journal reports. The ride-hailing company is testing new software in an updated version of its app that will use smartphone sensors to determine changes in a ride's pacing and smoothness. The update is meant to give drivers more comprehensive feedback if they receive a low rating from a passenger.

Slow down, from your app

Here's how it will work: After each completed trip, a driver will be sent a summary, according to WSJ. The summary will reportedly include distinct "scores" for acceleration and braking. If a particular part of the trip doesn't go well (a sharp turn, sudden braking), the location of the incident will be highlighted on a map. And if a driver breaks the speed limit, the app will send a warning in real time, WSJ reports.

WSJ also notes that an entirely different update is being tested in separate cities, which will track when drivers touch their phones. Presumably this is to discourage drivers from things like texting or making phone calls during a trip.

Although these updates are still in the testing phase, they raise significant privacy issues — something Uber has been criticized for several times. The updates will almost literally track every move a driver makes. There's also the issue of whether or not the information will be accurate — WSJ points out that the update doesn't account for a driver who might swerve to avoid hitting an animal. On the other hand, Uber says the data will provide objective, readily available information if a driver thinks he or she has been rated unfairly.

The update will reportedly begin rolling out tomorrow to nine US cities, including New York City and Los Angeles.

Ordering Uber with an Amazon Echo