Yellowstone

While we were in Yellowstone, we came across one of those dreaded coffin buses. Tour buses that not only take tourists around during the day, but house them at night as well; front half for the day, rear for the night. The right rear side pops out, has some canvas for walls, a stairway to a platform, and provides access to the sleeping slots. The tourists in them tend to be Japanese, but we've talked to some Germans traveling in one before too.

A clever use of existing technology, but they look pretty tight to me. They look worse than that to my claustrophobe wife.