A tax on the miles you drive could be a way to pay for Texas roads in the future. Texas transportation planners are studying the idea of a “mileage meter” to help raise money. Cars built after 1999 have a computer port that can access many types of data about the vehicle. Progressive Insurance already offers a device that connects to that port for pay as you go rates. “Mileage does have a lot to do with it,” said Mike Leonard, a Progressive insurance agent in Carrollton. “The less the miles, the less exposure Progressive has. So therefore, they’re willing...