Collision between two trucks just after a tunnel

A fully loaded truck is driving along the Takamatsu Expressway towards Kanonji (Kagawa prefecture), just past the Yamanoue tunnel. It's driving along at a leisurely pace when another truck comes up behind it and collides violently. The video clearly shows the brutal impact. On impact, a brownish dust spreads everywhere - impossible to know what it is exactly. The lead truck was heavily laden, and given the scene, the material damage is likely to be considerable. The human consequences are not yet known.