Free Stuff: a lifeboat in an emergency

I was thinking, since the quake and tidal wave of 2012 in Japan, why are cars not being designed to be lifeboats? Maybe with a giant expandafoam pack roof so a giant structure forms to indicate its location, protect the vehicle as a barrier as expanding foam in a shaped bag forming catamaran hulls drop from each side so it becomes a gondola hanging below a catamaran of foam in a bag.