The notion of tracking cars for insurance purposes tends to polarize us: it's either a technical marvel that gives an honest appraisal of how we drive, or a dystopian nightmare that makes it impossible to have a little fun without a large bill. MetroMile is banking on more of us taking the optimistic view. It claims to have the first 'true' pay-per-mile car insurance, and combines a fixed base fee with mileage derived from a tracking device attached to a given vehicle. Weekend drivers can theoretically save 20 to 50 percent, and any customer can see detailed analytics online. The catch, of
