Safety glazing material is marked with the manufacturer's distinctive designation or trademark, model number and the letters “AS” followed by a number from 1 through 16B, which indicates where the glazing may be used on the vehicle. Safety glazing material also has the symbol “DOT” (Department of Transportation) and a manufacturer’s code mark that the NHTSA (National Highway Traffic Safety Administration) assigns to the manufacturer. Any questions regarding glazing shall be referred to the Automotive Safety Enforcement Division of the Department of State Police. Proper Marking and Operation. Signs and Materials on Windshield or Windows. Inspect all glazing for unauthorized material or conditions that obscure the driver's vision. Post Manufacture Window Tinting. Definitions. “Acute area” means the windshield area 8 inches wide by 5 inches high, located directly in front of the driver, centered vertically on the steering wheel of the vehicle and horizontally in the center of the critical area. “Cloudiness” means any degree of visible discoloration or separation, except tinting that does not affect clear vision. “Critical area” means the normal windshield wiper sweep, except the area obscured by the hood, fenders, or rearview mirror. “Discoloration” means a condition which impairs the transparency of the glazing. “Non-critical area” means all windshield area outside the critical area. “Normal windshield wiper sweep” means the area of the windshield cleaned by the windshield wiper, excluding the return position on both passenger's and driver's sides. Glazing Damage.