You’ve probably seen the ads on TV claiming that good drivers can save up to 30 percent on their car insurance. All you have to do is plug a small tracking device into your vehicle’s diagnostic port under the dash and drive.Data such as sudden changes in speed, how much you drive – even where and when you drive – is transmitted to the insurance company and analyzed to see if you qualify for a lower rate – or not.Of course, everyone believes they’re a good driver and should pay less, which accounts for the growing popularity of Progressive’s Snapshot,
