How can this be legal?

Semper said
Louisiana State Police Begin Enforcing New Left-Lane Law

Louisiana state troopers have begun enforcing a new law requiring drivers on multi-lane highways to remain in the right lane.

The state Highway Safety Commission says state police began enforcing it earlier this month.
Click to expand...

In the nearly 3 years since that article was written, I sadly have yet to see proper lane dicsiplin enforced and as far as I can tell the problem has not gotten any better.