New Hampshire Code of Administrative Rules
Saf - Department of Safety
Subtitle Saf-C - Commissioner, Department of Safety
Chapter Saf-C 3200 - OFFICIAL MOTOR VEHICLE INSPECTION REQUIREMENTS
Part Saf-C 3217 - GLASS AND GLAZING
Section Saf-C 3217.02 - Unauthorized Materials on Windows

(1) Official inspection stickers which are placed in accordance with Saf-C 3245.06(b)(3);

(2) Privilege stickers, such as naval base, military installation, road use tax, university or college parking or police department shall be placed on the windshield or any window ahead of the rear part of the driver's seat and not more than 3 inches in length or width;

(3) Any stickers or decals required by federal law on new or used cars, in the possession of a dealer;

(4) Official electronic toll collection transponders which are placed in an authorized position on the windshield; or

(5) Stickers or other nontransparent material shall be permitted on a rear window if the vehicle is equipped with exterior rearview mirrors on the right and left side of the vehicle that provide the driver with a clear and unobstructed view of the way to the rear of the vehicle and the stickers or other nontransparent material are attached along the perimeter of the rear window in such a manner that the inside rearview mirror provides a view of the way to the rear of the vehicle through the center portion of the rear window.