Clam Shell Doors are a type of door similar to suicide doors, with one main difference. The front door must be opened before you can open the rear door, similar to a clam shell, hence the name. With suicide doors, either the front or rear can be opened without the other door being open.
If both doors are open and then the front door is closed first, followed by the rear door, the doors won't close and could be damaged.
Vehicles that have Clam Shell Doors: