Well under no circumstances do I think the OP is trolling anything. The appearance of a rainbow is a complex phenomenon and is influenced by many things. It isn't just reflection, it is reflection and refraction - and while driving through rain and spray you have a lot of that going on in multiple locations. What the OP observed is no doubt what he reported and photographed.
My comments were initially directed to the poster that said they had "chased down" the end of a rainbow many times and at least once saw it ending in a puddle. That is entirely impossible as one cannot under any circumstances "chase down" a rainbow. It will always appear to be ahead of or in front of you no matter what your location, you can never arrive at the rainbow's location since it does not exist. However, driving in a moving car with chaotic rain spray and the intervening interface of the windshield glass is completely different. Here you may actually be observing multiple rainbows overlaid onto your visual field which may indeed give the impression that you've "reached the end" of one of them.
Still though the fact remains that a rainbow is not a physical entity that can be approached in space, despite strong visual cues to the contrary under certain specific circumstances.