SAN FRANCISCO -- Opponents were gathering Wednesday for a public debate over a controversial plan that would require drivers pay to use San Francisco's traffic-choked corridors in the Financial District, South of Market and elsewhere throughout the center core of the city.

The plan would require drivers using certain city streets during rush hour to have their vehicles equipped with a transponder – similar to the FasTrak devices used by bridge commuters.

“The technology is there for us,” Jose Luis Moscovich of the San Francisco County Transportation Authorities told KTVU. “It has been proven in other cities and countries. It will be similar to the bridges. You drive through, you don’t stop, you get picked by transponder and a bill is sent to your house.”

Officials are gathering public comment to see if they should fund a three-year, $1.3 million study of the “congestion charging zones.”

Congestion pricing zones are already used in such European metropolises as London, Rome and Stockholm but has yet to be enacted in the United States. San Francisco joins New York City and Washington, D.C., in contemplating such a plan.

In London, cameras snap photos of license plates, and drivers must pay the charge either before or on the day of travel. They can pay by telephone, text message, online, mail or in person at designated stores.

On a typical day there are about 1 million trips in and out of San Francisco's downtown, South of Market and Civic Center neighborhoods. The average speed on many of those streets is less than 10 mph.

Officials say the fee would help ease congestion and raise much needed funds to pay for street maintenance and public transportation.

Among the issues confronting city transits officials are how much to charge, whether the fees should be applied only during certain hours, what specific streets or neighborhoods would be targeted and which drivers should be exempted from paying.