Illegal to Block Sidewalk

CA Vehicle Code
CHAPTER 9. Stopping, Standing, and Parking [22500 - 22526]
22500. A person shall not stop, park, or leave standing any vehicle whether attended or unattended, except when necessary to avoid conflict with other traffic or in compliance with the directions of a peace officer or official traffic control device, in any of the following places:
(f) On a portion of a sidewalk, or with the body of the vehicle extending over a portion of a sidewalk, except electric carts when authorized by local ordinance, as specified in Section 21114.5. Lights, mirrors, or devices that are required to be mounted upon a vehicle under this code may extend from the body of the vehicle over the sidewalk to a distance of not more than 10 inches.
Sidewalks in San Francisco are 6 feet wide made of two concrete squares. You can't legally temporarily block a sidewalk. * Except as a general rule SFMTA officers do not ticket vehicles parked in driveways that block the sidewalk during the 2 hours of street sweep.