FWIW: This link is not accurate as far as Illinois is concerned. You can legally tint front driver and passenger windows 35% as of I believe 2009.
Well that's AAA for you, as long as you pay their fee they don't seem to care to do their research completely.
On the Illinios .gov website it sorta states the same, but has exceptions.
Illinois General Assembly - Illinois Compiled Statutes
"(a-5) No window treatment or tinting shall be applied to the windows immediately adjacent to each side of the driver, except:
(1) On vehicles where none of the windows to the rear of the driver's seat are treated in a manner that allows less than 30% light transmittance, a nonreflective tinted film that allows at least 50% light transmittance, with a 5% variance observed by any law enforcement official metering the light transmittance, may be used on the vehicle windows immediately adjacent to each side of the driver.
(2) On vehicles where none of the windows to the rear of the driver's seat are treated in a manner that allows less than 35% light transmittance, a nonreflective tinted film that allows at least 35% light transmittance, with a 5% variance observed by any law enforcement official metering the light transmittance, may be used on the vehicle windows immediately adjacent to each side of the driver.
(3) (Blank).
(4) On vehicles where a nonreflective smoked or tinted glass that was originally installed by the manufacturer on the windows to the rear of the driver's seat, a nonreflective tint that allows at least 50% light transmittance, with a 5% variance observed by a law enforcement official metering the light transmittance, may be used on the vehicle windows immediately adjacent to each side of the driver."