1) Lyft drivers operate similar to a taxi and wait around until they are summoned via the app to give someone a ride.

2) It's not helping the environment more than cabs, and probably does more damage than cabs. I've seen a Ford F-350 Superduty with a pink mustache picking someone up. Cab's are usually Toyota Prius'.

3) As of recently, it's not cheaper than a cab.

4) It does allow drivers, who often have full-time jobs during the day, make extra money on the side.