Apron parking - parking in the driveway of a building so as to block the sidewalk - has always been illegal but cars so-parked were not ticketed in the past. A lawsuit noting that access for disabled persons to the sidewalks was obstructed was part of the reason for the new enforcement policy.
It appears that the Westwood-area ban on apron parking is now spreading to other LA neighborhoods, thanks to the lawsuit. See http://www.theeastsiderla.com/2011/09/silver-lake-drivers-discover-that-part-of-their-driveways-are-no-parking-zones/
A video was made in the UCLA area in support of the lawsuit under the Americans With Disabilities Act of 1990 (ADA). It deals with apron parking and other problems of sidewalk access: