thoughts: fuel leak rinses to the lowest point of the street gets nice and cloudy with any car driving thru. Trucks come with hot breaks down the road and do not see any danger. Pufff, classic cigarette realised with using the breaks down the road. Wave form of force travels thru air moving the air and with it the metal sheet (street), knocks exactly most where the force is most expansive and still filled enough to burn. Followed be reverse implosion, amplification of force in the opposite direction. The rest is a card house game. It breaks where it is most weak. To me the boat tnt, truck tnt and rocket tnt theories don't match up - the most obvious can be - well to obvious to be true or not?