Actually, it is the water vapor by-product of combustion and fuel cell
operation that I had in mind.

BMW's H-powered 7-Series deposits a noticable puddle at the rear while
idling. I just picture such vehicles behaving like Zambonis during the
winter months, paving the roads with fresh ice as each car passes by.

Is there any solution to this besides containment - capturing the water
and draining at intervals?

.