(a) The department may purchase, construct, maintain, operate, or control a ferry that crosses:
(1) a bay, arm, channel, or saltwater lake emptying into the Gulf of Mexico;
(2) an inlet of the Gulf of Mexico; or
(3) a river or other navigable body of water.
(b) This section applies only if:
(1) the ferry connects designated state highways; or
(2) the ferry connects a designated highway of this state and a designated highway of an adjoining state that by statute provides for the acquisition, construction, and maintenance of a ferry jointly by the states and for public use of the ferry as the states agree.