It's tough to blame just him. He was the engineer of the project, but the mistake should have been caught by the third party that checked it. It's the same reason the Hyatt Regency walkway collapsed in the 80s. The bridge never should have even began construction. On top of that, once the cracks were found, no cars should have been allowed to drive under the bridge. The road should have been closed, especially when work was being done to the bridge. While he was responsible, it's not like he was a bad engineer. He has won hundreds of awards for bridges he's designed. The cause of the collapse was the fact that his mistake was not caught and that cracks in the bridge were ignored. However, he also downplayed the severity of the cracks.

Trucks are required to have back up alarms by Federal Regulations. It is part of the pre-trip inspection. However, when you work in these zones as I have, you become numb to the sounds. That's why it is critical to always be alert and when backing to have a spotter.