In an effort to extract more money from its drivers, the Uber cab company has been pushing them to use Uberpool
where riders traveling to similar destinations are grouped together in the same vehicle.
This sounds great in theory, the Uber cab driver can carry more riders, but the downsides are several. First, the cab driver has to go out of their way to pick up the second (or third) rider, this leads to the second issue where the rider "experience" is degraded because the other riders might be undesirable in one way or another or their trip delayed because of picking up the other riders. This can lead to lower ratings for the cab driver, not to mention the cab driver gets fewer tips this way.
However, if an Uber cab driver refuses to accept rides using Uberpool they are penalized by the Uber cab company via "timeouts". The company prevents the cab driver from obtaining any other rides for up to 15 minutes.
As one researcher into how the Uber cab company operates via this method said, "You're saying to someone -- you're your own boss, but also go into the penalty box because you didn't behave in the way that we suggested you should."