Listen to John Schmidt talk about street names on Eight Forty-Eight
Every so often, you'll hear a visitor to our city ask for directions to Madison Avenue. This will make a true Chicagoan's blood boil. The dumb tourist doesn't even know it's supposed to be Madison Street.
Actually, there is no special rule on what is called a Street, and what is called an Avenue. It's merely traditional usage.
But the other suffixes! Here we get into some technicalities. At one time there was a whole protocol on how a suffix would be used on Chicago thoroughfares.
Let's take Boulevard.