I don't see any signs of an explosion. I see a forward debris field. A high speed crash with a sudden stop, and momentum carrying car parts forward. As a first responsder I've seen maany car crashes like this that ended with a sudden, and complete stop. Also light plane crashes where the crash angle caused a sudden, and complete stop,I've seen this, where the debris field was only in front.
Also, all the windows are intact on the toll booths indicating a LACK OF an explosive shockwave.
But, if some need to think it was an explosion, it has no affect on what I see or think. I personally view it as there are enough real events occurring without borrowing trouble.