A certificate issued under the provisions of this chapter may be revoked or suspended by the chief of police if the holder thereof has violated any of the provisions of this chapter, discontinued operations for more than thirty days or has violated any provisions of this code or the laws of the United States or the state, the violations of which reflect unfavorably on the fitness of the holder to offer public transportation. Prior to suspension or revocation, the holder shall be given notice of the proposed action to be taken and shall have an opportunity to be heard. (Prior code § 22-2-10)