Oregon is about to embark on a first-in-the-nation program that aims to charge car owners not for the fuel they use, but for the miles they drive. The program is meant to help the state raise more revenue to pay for road and bridge projects at a time when money generated from gasoline taxes are declining across the country, in part, because of greater fuel efficiency and the increasing popularity of fuel-efficient, hybrid and electric cars. Starting July 1, up to 5,000 volunteers in Oregon can sign up to drive with devices that collect data on how much they have...