All police officers appointed by the Superintendent of State Police, and engaged in the enforcement of criminal laws and the laws relating to the operation of motor vehicles upon the roads and highways of this Commonwealth, shall, before entering upon or continuing in their duties, enter into bond, with some solvent guaranty company authorized to do business in this Commonwealth, as surety, in the penalty of $75,000 and with condition for the faithful and lawful performance of their duties. Such bonds shall be filed in the office of the Department of State Police, and the premiums thereon shall be paid out of the funds appropriated for the maintenance and operation of the Department of State Police. All persons injured or damaged in any manner by the unlawful, negligent or improper conduct of any such officer while on duty may maintain an action upon such bond. In lieu of posting bond as provided herein, any such police officer may furnish an adequate liability insurance policy as proof of his ability to respond in damages, which may be adjudged against him in favor of any person or persons injured or damaged in any manner resulting from his unlawful, negligent or improper conduct while on official duty, to the amount set forth above. The premiums on any such insurance policy or policies shall be paid out of the funds appropriated for the maintenance and operation of the Department of State Police. All such bonds and insurance policies shall be approved by the Superintendent of State Police.