Uber uses a program known as grayball to help its drivers to avoid picking up law enforcement agents who look to ticket the drivers for using Uber in cities where the app is illegal. The program is also helpful for Uber drivers to avoid picking up people who may wish to do them harm.
How Uber Deceives the Authorities Worldwide
Uber’s use of Greyball was recorded on video in late 2014, when Erich England, a code enforcement inspector in Portland, Ore., tried to hail an Uber car downtown in a sting operation against the company. At the time, Uber had just started its ride-hailing service in Portland without seeking permission from the city, which later declared the service illegal.