you cant see most of the block its underground, look just behind the impact site when the dust settles, they are huge weighing loads and shaped like a big wedge to disperse the impact downwards into the ground and away from the wall on a 45 degree angle, thats why the front of the truckstops dead and the back goesup in the air
i remember seeing it on discovery channel about anti terrorist thingys lol
they also using them in towerblocks etc, youd be dead impressed if it stopped a truck bomb from taking out a building if you was in it, which is what they was designed for
They are basically steel re-enforced walls which will go down about 50mtrs and when done properly will withstand almost anything, I used to be a steel fixer and built some blast walls/buildings at Fort Halsted in kent which is a M.O.D phorensic facility, the walls there were supposed to be able to take a nuclear blast