Damn. Are you planning to survive your trip, or die before ever seeing home again? In local terms, flashing his lights before you flashed yours means he's got the right of way. Doesn't matter how weird, nonsensical or downright evil you think this is. You don't make the rules.

More to the point, sooner or later you're going to toss a stone at the wrong local, and things are not going to go well for you (or Ellen). Setting aside the question of right vs. wrong (yeah, of course he's a jackass), it's really a matter of survival--and I mean yours, not his. If you are routinely getting run off the road as it appears--in Peru or elsewhere--you need to decide whether you'd rather expend your energy feeling righteously indignant while continuing to do what you've been doing, or whether you'd rather re-dedicate yourself to staying alive. It's really your choice.

All IMHO, as usual. But there's another aspect to this: that guy whose headlight you potted: what do you suppose he's going to do next time he sees an overloaded tourist on a giant, lumbering bike? You think he's going to meekly pull over to his side of the road, cowering? Uh huh. He (or the next, or the next) is going to aim right for that bike, no messing around about it. And who do you think is going to pay the price? What you ought to be thinking right now is that you really don't want to encounter any truck drivers who just passed a stone-throwing tourist on an overland bike.

Mark