As SFpark is envisioned, parking rates would be adjusted based on time of day, day of week and duration of stay. People would be able to pay not just with coins, but with credit cards, prepaid debit cards and even by cell phone. If a meter is set to expire, a text message could be sent to the driver. More time could be purchased remotely.

People also would be able to check parking availability before arriving at their destination via the Internet, handheld devices such as BlackBerrys, or cell phone. Sensors would be embedded in the asphalt to keep track of when a parking spot is empty....

"The idea is to give people more choice, more convenience and to reduce congestion," said Mayor Gavin Newsom.

Under the program, which will focus on 10 neighborhoods, the city will adjust hourly parking rates based on demand - the price will go up when spaces are scarce and go down when plenty are available.

People may be less inclined to drive during peak times if they know it will cost them more.

