Rli Insurance Company v. Duncan.

a certificate of insurance for such applicant or holder ... evidencing a policy of indemnity insurance by an insurance company licensed to do business in this state, which policy must provide for the protection, in case of passenger vehicles,

The statute authorizes the Department of Insurance "to permit self-insurance, in lieu of a policy of indemnity insurance, whenever in its opinion the financial ability of the motor carrier so warrants," and it also empowers "any person having a cause of action [against a motor carrier] to join in the same action the motor carrier and the insurance carrier…