The following materials are incorporated by reference as of the edition date provided below. No later amendments to or editions of the following documents are incorporated. Copies of these materials are available for inspection at the Department's Commercial Vehicle Safety Section at the address provided in Section 460.130.
The opacity cutpoints recommended by this guidance that will be used as a standard for this program shall not exceed: 40% opacity for vehicles model year 1991 and newer; 55% opacity for vehicles model year 1974 to 1990 and older.
Ill. Admin. Code tit. 92, § 460.140