The service is not outside of business standard variety. Other cab companies have client driven matchmaking systems too now... They also employ office workers. The workplace for a cab driver is his car.
Therefore, what Uber does would make them a cab company that abuses contractors instead of employing employees.
However, the key point here is the test A. If Uber is specifically telling the drivers to pick up specific fares or otherwise forcing them to pick up fares beyond the number and/or time, they are actually employees not contractors. Fudging with scoring system to fire those who do not follow such orders indirectly could be construed as such as well.