They get more distracted by the phones I believe. Specially in between rides when they have to accept ride requests in a timely fashion.

I've seen drivers parked in lots when they are awaiting a request but in places where parking is charged such as downtown, I think they prefer to keep looping around blocks.

There may be an interesting case study to be made on the environmental impact of these idling cars.

Also, some drivers are lazy and don't get proper mounts for their phones. I've had a few Lyft drivers spend much of the ride with their faces buried in their phones because they didn't bother to get a mount and don't want their nav to speak out loud.

I also had one reckless idiot spend the whole ride texting while driving, too.

In NYC, where Uber/Lyft drivers are required to operate Taxi and Limousine Commission-licensed cars, citizens can file complaints via the web, leading to tickets: https://twitter.com/hashtag/cyclistswithcameras