In August 2013 I wrote a posting about how Boston’s Longfellow Bridge would cost at least 4X to renovate, in constant dollars, what it cost to build with circa 1900 construction techniques. In January 2015 I added a posting about a rumor that the project was a year behind schedule. I found this August 2015 WBUR article saying that the project has been delayed for an additional two years and that the projected budget was substantially higher than I quoted in my original posting. Thus it seems that, if there are no additional setbacks, the renovation will take roughly as long as the original construction and cost about 6X as much, after adjustments for inflation.
I’m thinking that even if Bernie Sanders gets elected and Congress gives him the $18 trillion that he wants to spend (WSJ), the country won’t look substantially different in terms of infrastructure.