Again there is no surface damage to the roadway. Stop frame at the 2 second mark to see boat bow. When viewing filmed explosions, stop frame is your friend.
A truck bomb could not do the damage we see, without major damage to surface of roadway, and likely could not do any of the damage visible.
I can see the wake of something in the water, immediately before the explosion, so it may well have been the origin.
But it was clearly targeting the road - when the rail is far more important to Russian logistics.
I’d have expected an attack on the rail, and I don’t see how anyone could have expected an attack on the road to take out the rail as well.