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, according to the San Francisco Chronicle. The congestion toll, if implemented, would be the first in the nation.

The congestion toll plan would also offer discounts to some drivers -- including taxi drivers -- who would not have to pay. Commercial vehicles, rental cars and car-sharing vehicles would pay a lower fleet rate. Low-income and disabled drivers and residents of the toll zone would pay half, and drivers who paid bridge tolls would get a $1 discount.

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 Nov. 25 at a meeting of its board. The board won't consider recommending a congestion toll plan until February.

Similar tolls, also known as cordon tolls, have been used in London and Stockholm, where they're credited with reducing traffic congestion, air pollution and miles driven. They also have raised tens of millions annually for public transportation improvements.

The toll would be collected on weekdays between 6 and 9 a.m. and 4 and 7 p.m., meaning the average car commuter would pay $6 a day in congestion tolls. The fees would be collected using FasTrak transponders and a network of cameras. Motorists would be able to pay via phone, the Internet or retail outlets.

The congestion toll could raise between $35 million and $65 million a year, money that could be invested in transportation improvements, with an emphasis on boosting service and capacity on Muni, BART and other transit agencies that serve San Francisco.