San Francisco Chronicle: Drivers could pay $3 to enter, leave or pass through parts of San Francisco during morning and evening commutes under a proposal designed to push motorists out of their cars. The San Francisco County Transportation Authority, which has been studying the idea of imposing congestion-based tolls on city streets for nearly two years, released some of the details of its study Tuesday at a meeting of its board, which is made up of the 11 members of the Board of Supervisors. The board …