A couple things to note: 1) Average driver drives ~13.5K miles/year (http://cars.lovetoknow.com/about-cars/how-many-miles-do-americans-drive-per-year http://ca

A couple things to note: 1) Average driver drives ~13.5K miles/year (http://cars.lovetoknow.com/about-cars/how-many-miles-do-americans-drive-per-year http://cars.lovetoknow.com/about-cars/how-many-miles-do-amer...) with an average speed of ~32 mph (http://www.ridetowork.org/transportation-fact-sheet http://www.ridetowork.org/transportation-fact-sheet). This translates into 420 hours/year. Or a person becoming an expert driver by the age of 40, if we accept the "10,000 hours rule"... 2) But the Gladwell's "10,000 hours rule" was proven wrong (http://journals.sagepub.com/doi/abs/10.1177/0956797614535810 http://journals.sagepub.com/doi/abs/10.1177/0956797614535810). For example, if we follow FAA that recently changed the rules to require 1500 hours for ATP (i.e. airline pilots) license, then you are talking about 3.5 years (for average driver) vs. 9 months (for taxi driver). Not that big of a difference. This means that on average the US driver becomes an "expert" by the age of 21-22. This actually matches quite well with the insurance company rates that drop drastically at about this age.