I live in Sunderland. I don't know how high the bridge is in feet. But I can tell you a lot of people have managed to ctb by jumping off. But a lot have survived it. People either land in the water or on the concrete paths. The bridge is well lit. The Police, Taxis etc. are always on the lookout for potential jumpers. So it's not the easiest place to jump. It's usually always quite busy aswell.