Essentially, without knowing who drove how much, car insurance companies have historically had to overcharge most people to subsidize high-mileage drivers. But thanks to the advances in mobile technology, Metromile invented a cellular GPS telematics device that plugs into your car’s diagnostic port under the dashboard, and reports back how many miles you drive. The startup’s $14 million in funding from First Round Ventures, SV Angel, NEA, and Index Ventures let give away its telematics devices and white-label a major insurance carrier with its per-mile system.

http://techcrunch.com/2014/07/16/per-mile-car-insurance/