OAKLAND  (AP) — San Francisco Bay area officials will study a proposal to charge motorists a tax on every mile they drive in the nine-county region as a way to raise money for roads and public transit while reducing traffic and pollution from car emissions.

Members of the Metropolitan Transportation Commission and the Association of Bay Area Governments approved going forward with further study of a possible Vehicle Miles Traveled tax on Thursday night, as part of a broader environmental review of several transportation options.

Under a proposal still in its early stages, drivers could be required to install GPS-like odometers or other devices in their vehicles and pay from less than a penny to as much as a dime for every mile driven. The idea could take a decade or more to be launched.

Commission spokesman Randy Rentschler acknowledged such a concept ultimately could prove a hard sell with Bay Area residents, who would likely resist both the travel tax and the government-mandated tracking devices.

"The last thing we're interested in is where you go and what you do," Rentschler said Thursday, after the vote. "What we're trying to do is get people to figure out a way to raise revenue that they could support."

Mileage taxes already have been subjected to pilot studies in Atlanta and several communities in Oregon and Washington state. Drivers who were given a sum of money and then had amounts deducted based on how much they drove logged fewer miles, according to the San Jose Mercury News (http://bit.ly/Q4NbSP ).

Based on current Bay Area driving patterns, a mileage tax could raise up to $15 million a day, the Mercury News said.

The two regional agencies are considering the tax as part of a broader, 25-year transportation and land-use plan to accommodate the 2.1 million new residents who are expected to reside in the Bay Area and to curb greenhouse gases.

Other ideas floated so far include raising bridge tolls during rush hour, creating more carpool lanes and funding public transportation options in counties north and east of San Francisco.

The draft environmental review is scheduled to be completed in January and the tax, as well as many other alternatives, will be presented for a vote in April, Rentschler said.