First of all a freshly graduated engineer will never be signing off on a bridge used by millions of people a years. More importantly designing a bridge using a

First of all a freshly graduated engineer will never be signing off on a bridge used by millions of people a years. More importantly designing a bridge using a century old design, well understood materials, and sticking to all the well known, well documented and legally mandated best practices we have accumulated over the years is an entirely different skill than trying to come up with a novel and better way of designing or building a bridge and then conclusively proving that it is still at least as safe as the old way of building a bridge.