In Illinois when taking the tests for a class B, they have a seperate segment test for air brakes. If you pass it with 80% or better and pass the general knowledge section, then you receive an unrestricted class B. If you cannot pass the air brake segment, you still get a class B....but you also receive an "air brake restriction", meaning you can operate ANY GVWR non-articulated commercial vehicle that DOESN'T have air brakes.