Well, the NAFTA Highway is a term borne from and used mainly in conjunction with conspiracy theories about the North American Union, thanks in large part to the creation of the European Union, which effectively eliminates the borders, at least with regard to trade, with the US, Canada and Mexico.
Just the notion of a highway connecting Mexico and Canada through the US causes many people to crap themselves. They are apparently oblivious to I-5/I-15 and I-29/I-35, the eventual connection of all the various bits and pieces of I-69, and the fact that by negotiating the occasional traffic light and left turn it's really rather easy to get from Mexico to Canada via the US already.
In any event, if you think Del Rio to Taylor contains too few miles of Interstate highway, pray you never get a load from El Paso, TX to Roseau, MN.