From today's Press Citizen:
Derek L. Butterfield, 20, and friend Terry Holmes were on their way to Iowa City when their car ran out of gas about a half-mile west of the I-80 overpass of Highway 6. Butterfield and Holmes started to walk along the interstate to get help. They decided to cross the median area when Butterfield, apparently unaware he was on a bridge, jumped over the concrete barricade and instead of landing on the median fell to Highway 6 below. Holmes witnessed the fall and officers responded about 2:17 a.m.
Police think alcohol might have been involved,...
Really? No way!
So to recap, jumping off bridge into river and then going over the dam is dangerous, but can possibly be survived. Jumping off bridge onto paved highway, not so much.