public Collection<PhysicsVehicle> getVehicleList(){
        return new LinkedList<PhysicsVehicle>(physicsVehicles.values());
    }
Removes all physics controls and joints in the given spatial from the physics space
(e.g. before saving to disk) - recursive if node
@param spatial the rootnode containing the physics objects
jme3-jbullet/src/main/java/com/jme3/bullet/PhysicsSpace.java