Alleys are driveable roads that often provide access to the rear of a business or residence. They can be an important part of the map for routing purposes especially for places with rear access only and for drivers starting a route from an alley.
Guidelines for Mapping Alleys in Illinois:
Generally speaking, only residential alleys should be mapped, and only if they are the locally accepted destination for parking at or near a residence. Alleys should only function as a starting point or final destination, not as a thoroughfare.
In the city of Chicago and the suburbs, do not delete already mapped alleys. Outside the Chicagoland area, alleys may be deleted if they are not necessary for proper routing.
If an alley is to be mapped or updated, be sure to nudge the house numbers.
Road type should be set toand should be named "Alley".