THE C/DII: Owning a car in a city is expensive. And when it comes to insurance, where you live can be a major factor in whether you can afford the car of your dreams. The
Car and Driver Insurance Index ( C/D II) is based on a six-month insurance premium for a 2010 BMW M3—garaged, owned, and operated by a 37-year-old, married male living in each of the selected cities.
Article source: http://www.caranddriver.com/features/09q4/2010_10best_drivers_cities-10best_cars