Section 6. No motor vehicle shall be operated under any license issued under this chapter until the licensee, in addition to complying with all orders, rules and regulations of the licensing authority, shall have deposited with the state treasurer a bond, running to him in such sum as the department may reasonably require, with a surety or sureties or other security approved by the state treasurer and by the department, conditioned to pay any final judgment obtained against the principal named in the bond for any injury to person or property or for damages for causing the death of any person by reason of any negligent or unlawful act, on the part of said principal, his or its agents, employees or drivers, in the use or operation of any such motor vehicle. Any person so injured or damaged, or his executor or administrator, or the executor or administrator of any person whose death was so caused, may enforce payment of such judgment by suit on said bond in the name of the state treasurer, and in such suit the court may make any appropriate order for the application of any security deposited as aforesaid. If any liability insurance policy filed as security for any such bond, or any such bond with a surety company as surety, shall be cancelled or a renewal policy or bond is not filed prior to the expiration thereof, or if the state treasurer or the department at any time after notice and hearing shall determine that the sureties on any such bond or the security therefor is not sufficient, or if the department shall in its discretion determine and notify the licensee that a larger bond is required, no such motor vehicle shall thereafter be operated until the licensee has furnished other or additional security approved by the state treasurer and by the department. No security other than as herein provided shall be required of any such licensee.