Pennsylvania Vehicle Code
1332. Display of registration plate.
(b) Obscuring plate.--It is unlawful to display on any vehicle a registration plate which:
(1) is so dirty as to prevent the reading of the number or letters thereon at a reasonable distance;
(2) is obscured in any manner which inhibits the proper operation of an automated red light enforcement system in place pursuant to section 3116 (relating to automated red light enforcement systems in first class cities) or 3117 (relating to automated red light enforcement systems in certain municipalities) or any other automated enforcement system authorized by this title or an electronic toll collection system as authorized under 74 Pa.C.S. § 8117 (relating to electronic toll collection);
(3) is otherwise illegible at a reasonable distance or is obscured in any manner; or
(4) is obscured, covered or otherwise obstructed in a manner which inhibits the visibility of the issuing jurisdiction at a reasonable distance.
(c) Penalty for obscured plate.--Any person who violates subsection (b)(2) or (4) commits a summary offense and shall, upon conviction, be sentenced to pay a fine of $100.