Definition
Drivers and walkers need visibility where alleys enter streets and where a driveway crosses the sidewalk.
These clear vision areas are smaller but are just as important to drivers and walkers. For alleys and driveways, this areas is measured into the lot from the inside edge of the sidewalk and along the street, away from the driveway or alley. The same 30 inch rule applies in these areas.
Resources
If your area does not have a sidewalk, measure this area starting from the property line, usually about seven feet behind the edge of the pavement.