When a 900-foot container ship struck the San Francisco–Oakland Bay Bridge in 2007, the span stood firm and no one died, either on the ship or the highway above. The bridge's supports were protected by a fendering system of concrete and other materials that was installed to absorb such strikes. Sherif El-Tawil, a University of Michigan engineering professor, said there are several safety measures that “would have made a huge difference” had they been in place Tuesday morning when a cargo ship plowed into the bridge and caused its collapse.