Trans-Texas Corridor?

So according to Digg there are now signs up in Texas advertising a highway called the Trans-Texas Corridor which supposedly will connect the US and Mexico when the NAU fully develops. Unfortunately the site linked to from digg is Infowars (which seems to be a perfectly reliable source for diggers it seems) so I had some doubts about the legitimacy of the very image. I poked about wikipedia to find no real connections between the corridor and the whole NAU concept, so I figured I would post here to see what the take on the boards are? Is this thing going to stay inside the US or is it likely to be extended south to Mexico?

There is already a few threads on this, here is a recent one:
www.abovetopsecret.com...

another:
www.abovetopsecret.com...

A related thread:
www.abovetopsecret.com...