I have several cities on a continent, one city a good distance from the others. For whatever reason, traders will not go there from other cities, and will not leave from it, saying "No trade routes exist..." Why is that? How else to I get a road to and from this city? I know, use a Military Engineer! It's ridiculous that a ME can only build a road on a max of two tiles! I understand the two building charges for airstrips and silos, but for roads it makes no sense.