While homeowners don’t own the street and have no right to mar any car for blocking their driveway; you have every halachic right to call the police if you think a medical emergency may ensue.
There are numerous illegal driveways in Boro Park; i.e. 40th Street between 12 Ave. and 13th Ave. I’ll bet you won’t have any homeowners calling the police if their driveways are blocked. These driveways use up all available parking spots, so I wouldn’t care much if these driveways were blocked.