Light settings when driving through tunnel

HI!

Making an animation with a quite long tunnel implemented. As you can see in the first image the materials and light settings are pretty ok. Just some minor adjustments should be made. But once the animation continues and the camera goes into the tunnel it kind of looks like you have died and are on your way to heaven or sth. I understand that the incoming light from the other side of the tunnel will be quite strong, but why would the concrete material show clouds? It doesn´t make any sense at all. It´s not transperent or reflective or anything. It looks like it does in the first image.

 

Any suggestions?

/Dan