But were afraid to ask.

TL/DR . . . “bridges in the US are getting more ‘average’ over time. We have fewer excellent bridges, but we also have many fewer bridges in poor condition. We’re fixing our worst bridges, rather than spending money keeping bridges looking sparkling and new. Because the difference between a poor quality bridge and an ‘average’ bridge is much larger than an average and an excellent bridge (since a poor quality bridge is at risk of collapse), this means that bridge infrastructure is getting safer over time, even as it gets older and handles more traffic.”