None of the terms or prohibitions of § 95.21 shall apply to or be enforced against the following.
(A) Emergency vehicles. Any police or fire vehicle or any ambulance, while engaged upon emergency business.
(B) Highway maintenance and construction. Excavations or repairs of bridges, streets or highways by or on behalf of the village or the State of Michigan during the night when the public safety, welfare and convenience renders it impossible to perform such work during the day.
(O.C. § 6.11)