If you didn't hit the school bus, which have very long mirrors, then he was just too close to center. I've driven big trucks and never bumped mirrors with other big vehicles on the same kind of 1.5 lane country roads. But I've noticed that a lot of guys don't have a very good handle on where the opposite side of their vehicle really is. Especially SUV drivers. Instead of getting over to the side like they should, sometimes they're 2' or more from their edge. On full sized trucks and other wide vehicles, that's not a good thing. It's as if they don't know where their passenger side wheels are riding.