...and another thing...
look at the video again... it's riveting stuff.
Wind is from the trucks right, and the fireball and sparklers (additives) are coming from the right and behind the position of the truck,... as they would for a bomb set under the bridge and having a shock dispersed laterally and rising around the span. At that point, the pressure differential will cause an inflow into the area in the lee ops the explosion, and that seems to be observed, but it could be time to go to spec savers... (it is a wake effect at that point, separated flow, boundary layer sort of geeky stuff... )
Look at the on coming cars lights. it is proximate to the truck, having just passed it in the opposite direction, and a bomb apparently from Bulgaria in the truck arranged by the dastardly Ukrainians goes off with enough force to blow the phlegm out of the RH back spans, yet, doesn't muss up the green hair of the wig on the driver of the car that is beside it. Most times, when you have a bang that is big enough to drop a large bridge, it will give a bit of a shockwave and yet, didn't happen here. That may be cuz the bomb wasn't in the truck, despite the story from the FSB, but was under the span. We see the span underside that is on the other side of where the pier was to the detonation, a replay of the July 44 Valkyrie bomb D'oh!.