(a) Whenever authorized signs are erected indicating a zone of quiet, no person operating a vehicle within any such zone shall sound the horn or other warning device of such vehicle except in an emergency.
(b) Whoever violates any provision of this section is guilty of a minor misdemeanor on a first offense; on a second offense within one year after the first offense, the person is guilty of a misdemeanor of the fourth degree; on each subsequent offense within one year after the first offense, the person is guilty of a misdemeanor of the third degree.