Thanks for the pointers. I've never driven anything bigger than a 14-foot uHaul truck; don't really know how those coal trucks drive. But I have three chipped-stars on my windshield, all from trucks as they passed (I don't follow them close at all unless it's crawling traffic), and had vowed not to let that happen again. Not trying to rude, but if I were rude not letting them pass, they must be equally rude to not cover their rocky goods or at least prevent them from falling off and hitting those they leave behind.
In any case, the incident I was in, and you guys, taught me a few things. I want it to be my first and last incident.
p.s: Suze, I saw your post just as I entered mine. Yep, I was allowing those trucks to pass and got stones as thanks..but you're right, smart drives differently, and am learning even after 20,000 miles of it..