(a) The security required under this subchapter shall be made:
(1) by cash deposit;
(2) through a bond that complies with Section 601.168; or
(3) in another form as required by the department.
(b) A person depositing security shall specify in writing the person on whose behalf the deposit is made. A single deposit of security is applicable only on behalf of persons required to provide security because of the same collision and the same motor vehicle.
(c) The person depositing the security may amend in writing the specification of the person on whose behalf the deposit is made to include an additional person. This amendment may be made at any time the deposit is in the custody of the department or the comptroller.