Metromile is a car insurance company that has been a leader in the pay-as-you-go insurance marketplace. Their rates are calculated based on two components: a base rate composed of the rating for the vehicle type (think Porsche vs Toyota Camry) and the registered address (home address) of the vehicle a per-mile rate for a driver based on their driving history / available data In order to calculate the per-mile billing, the company issues you an ODB-II adapter (more on ODB-II).