Snapshot, Progressive's MPH tracker, is awful and completely impractical. It beeps obnoxiously whenever you "hard brake" more than 7 mph per second. If you're driving 45 MPH and brake at a constant 7 MPH / second, you will need 280 feet to completely stop. Progressive thinks you're "hard braking" if you have less than a football field to stop. Yeah, good luck with that.
SAFETY WARNING: Snapshot is probably unsafe for new drivers. It may cause them to hesitate in a situation where a hard brake is required to avoid an accident.
While I really like the concept of insurance rates being affected by real-world driving data, this system is so poorly thought out (counting 8 MPH/second as a "hard brake") that the only way to avoid getting beeped is to drive dangerously under the speed limit.
The final straw for me was when Snapshot claimed I was "hard-braking" while pulling into my driveway.