As of yesterday, you may be paying less to park in San Francisco. Or more! Or the same amount as you were before. Confused? Don't be, it's all part of the San Francisco Municipal Transportation Agency's SFpark program, which periodically resets parking rates depending on the demand for parking in a specific area.

According to the SFMTA, 19 percent of "metered hours" in the SFpark areas of Civic Center/Hayes Valley, Downtown, Fillmore, Fisherman's Wharf, the Marina, Mission Bay, and SoMa are decreasing by 25 cents, 13 percent are increasing by 25 cents, and 68 percent are staying the same price.

Every zone has increases, decreases, and no change at all, as you can see in this here map from SFpark delineating the new rates and fees.

This is the 18th demand-responsive rate adjustment since SFpark's smart meter system got rolling, the SF MTA says, and the fifth rate change determined by "meter payment data rather than parking sensor data."

To learn more on the SF MTA's rate adjustment methodology, here's a gripping 21-page PDF on the subject, and to download a spreadsheet of all of this round's rate changes, click here.