Look at any Interstate overpass and note the guard rails.
The guard rails are not to protect the posts, they are to guide a car away from colliding with the posts so the people inside aren't killed by the sudden stop.
If you look at the French tunnel, it still doesn't have guard rails so they didn't learn anything from the accident.
Oddly enough, I heard about the crash on the radio just as I was about to enter a different tunnel.