The Department may prescribe by regulation or order, as to public carriers operating charter buses, such requirements as it deems necessary for the protection of persons or property of their patrons and the public, including the filing of surety bonds, the carrying of insurance or the qualifications and conditions under which such carriers may act as self-insurers with respect to such matters. All such motor carriers, whose current liquid assets do not exceed their current liabilities by at least $100,000, shall cover each and every vehicle transporting passengers or property, with a public liability and property damage insurance policy or policies issued by an insurance company authorized to do business in this State, in such amounts as the Department may prescribe, but not less than $25,000 for 1 and $50,000 for more than 1 person injured or killed in any 1 accident, and not less than $10,000 for loss or damage in any 1 accident to property of others, excluding cargo.