It's a little sad and a bit ironic when a road scholar knows more that the state transportation department.
In trying to find out the history of the Melville Ferry, I contacted the Louisiana Department of Transportation and Development. I explained that I was trying to find out the history since the ferry is on an old alignment of US 71 (and possibly the old Jefferson Trail). The response I received was to the effect of "we think it's over 50 years old, but we don't know anything else".
You mean, what little I know is still more than LADOTD knows? That's so funny in the wrong sort of way.