ACK! My bad. Route 69 (changed to Route 31)was a real thing, but it was a state road, not an Interstate.
Point taken, but picture how much worse the problem would be if that was all being moved by individual trucks.
Well, free trade is almost always a good thing, but it’s much more complicated than just building an international highway. Central and South America would need to form closer bonds with each other similar to the European Union. Given that there’s much fewer language barriers between these countries it’s says a lot that they haven’t yet. Even the EU is far from a perfect utopia, witness Brexit (and they even had the freakin’ Chunnel*!*).
Well actually, eventually, they ARE moved by individual trucks. At least at some point of the line from port to customer. Most efficient is to load them first on trains, then on to trucks at a later terminal. Some go directly from ship onto a truck. But eventually a truck does move them. I looked it up and they said their are about 5.6 million semi trucks in the US.
So I think a best system would incorporate not just an interstate type highway all thru central America but also a good rail line and eventually a high speed rail line.
Consider Canada is about 5,000 miles wide and look how popular its train rides become and much of that is thru open plains, mountains, and forests.