Bridge height reference

I actually don't know how high to make this bridge. Fortunately, as with most things, here's one that's been prepared earlier. It's the pedestrian bridge linking james street mall with the perth train station.

Convenientastic.

Since I know that it will accomodate trucks etc, I can use the same height difference knowing that my bridge should be able to do the same. Unless Landgate have lied to me. the cad drawings on the bottom show that there's a 6.1m difference in height. You know, just in case a dinosaur needs to travel underneath or something.