(1) The security required under this chapter shall be in such form and in such amount as the department may require, but in no case in excess of the limits specified in RCW 46.29.090 in reference to the acceptable limits of a policy or bond.

(2) Every depositor of security shall designate in writing every person in whose name such deposit is made and may at any time change such designation, but any single deposit of security shall be applicable only on behalf of persons required to furnish security because of the same accident.