I believe regardless of the actual probability of failure, most people would have refused to drive across the bridge had they seen one of the supports had becom

I believe regardless of the actual probability of failure, most people would have refused to drive across the bridge had they seen one of the supports had become completely detached. Another way to put it is if authorities had closed the bridge in 2019, I believe most people wouldn't complain when they were presented the photo of the detached support. Also I don't think it's possible for your risk calculation to be done preemptively. We don't know the final breaking point of a piece of steel until we break it. All the calculations and modelling of the bridge will have been done with error margins and because of that we don't have any choice but to over-engineer things so we always stay outside of the worse-case margin for error. Given all that, I don't think it's unreasonable to expect the risk of a bridge collapse to be a lot lower than the average risk we take on the road.