BUT, the angle, the timing and the rain was just right so that as I started driving into the rain itself the rainbow appeared to end on the road ahead... then I could see the cars ahead of me driving THOUGH the rainbow. I could see the road ahead of me through the rainbow (and, believe me, that did a number on my depth perception). Then I was deep enough in the rain (or the sun was accluded by cloud for a bit) so the rainbow was no longer visible.
Seriously, people, I drove through the rainbow's end! It. Was. Awesome.
Alas, nary a pot of gold in sight.