Scroll to the bottom to read the question. For refernce, here is the Illinois seat belt law: (625 ILCS 5/12‑603) (from Ch. 95 1/2, par. 12‑603) Sec. 12‑603. Seat safety belts. (a) No person shall sell any 1965 or later model motor vehicle of the first division unless the front seat of such motor vehicle is equipped with 2 sets of seat safety belts. Motorcycles are exempted from the provisions of this Section. (b) No person shall operate any 1965 or later model motor vehicle of the first division that is titled or licensed by the Secretary of State unless the front seat of such motor vehicle is equipped with 2 sets of seat safety belts. (b‑5) No person under the age of 18 years shall operate any motor vehicle, except a motor driven cycle or motorcycle, with more than one passenger in the front seat of the motor vehicle and no more passengers in the back seats than the number of available seat safety belts, except that each driver under the age of 18 years operating a second division vehicle having a gross vehicle weight rating of 8,000 pounds or less that contains only a front seat may operate the vehicle with more than one passenger in the front seat, provided that each passenger is wearing a properly adjusted and fastened seat safety belt. (c) (Blank). (d) The Department shall establish performance specifications for seat safety belts and for the attachment and installation thereof. (Source: P.A. 89‑120, eff. 7‑7‑95; 90‑89, eff. 1‑1‑98; 90‑369, eff. 1‑1‑98; 90‑655, eff. 7‑30‑98.) (625 ILCS 5/12‑603.1) (from Ch. 95 1/2, par. 12‑603.1) Sec. 12‑603.1. Driver and passenger required to use safety belts, exceptions and penalty. (a) Each driver and front seat passenger of a motor vehicle operated on a street or highway in this State shall wear a properly adjusted and fastened seat safety belt; except that, a child less than 6 years of age shall be protected as required pursuant to the Child Passenger Protection Act. Each driver under the age of 18 years and each of the driver's passengers under the age of 18 years of a motor vehicle operated on a street or highway in this State shall wear a properly adjusted and fastened seat safety belt. Each driver of a motor vehicle transporting a child 6 years of age or more, but less than 16 years of age, in the front seat of the motor vehicle shall secure the child in a properly adjusted and fastened seat safety belt. (b) Paragraph (a) shall not apply to any of the following: 1. A driver or passenger frequently stopping and leaving the vehicle or delivering property from the vehicle, if the speed of the vehicle between stops does not exceed 15 miles per hour. 2. A driver or passenger possessing a written statement from a physician that such person is unable, for medical or physical reasons, to wear a seat safety belt. 3. A driver or passenger possessing an official certificate or license endorsement issued by the appropriate agency in another state or country indicating that the driver is unable for medical, physical, or other valid reasons to wear a seat safety belt. 4. A driver operating a motor vehicle in reverse. 5. A motor vehicle with a model year prior to 1965. 6. A motorcycle or motor driven cycle. 7. A motorized pedalcycle. 8. A motor vehicle which is not required to be equipped with seat safety belts under federal law. 9. A motor vehicle operated by a rural letter carrier of the United States postal service while performing duties as a rural letter carrier. (c) Failure to wear a seat safety belt in violation of this Section shall not be considered evidence of negligence, shall not limit the liability of an insurer, and shall not diminish any recovery for damages arising out of the ownership, maintenance, or operation of a motor vehicle. (d) A violation of this Section shall be a petty offense and subject to a fine not to exceed $25. (e) (Blank). (f) A law enforcement officer may not search or inspect a motor vehicle, its contents, the driver, or a passenger solely because of a violation of this Section. (Source: P.A. 93‑99, eff. 7‑3‑03.) Here is the line I don't understand: Where can I find these "performance specifications"? The law says nothing about having to have shoulder belts. Is there a cetain year that shoulder belts became federally mandated safety equipment?