CleverRaven/Cataclysm-DDA — pull request #3220 by kevingranade (2013-09-24 01:14:27+00:00)
Title: With a flag, fail placing a vehicle with add_vehicle() instead of simulating collisions.

This addresses unfolding a folding bike next to an existing vehicle, causing them to merge and hilarity to ensue.
Thanks to Winston84 for reporting.