I had lunch today with a friend of mine who grew up in Syracuse, and he was telling me about this.
https://auburnpub.com/blogs/eye_on_ny/grid-tunnel-or-viaduct-a-look-at-three-options-for/article_89a4313a-48ed-5121-addc-4f324d07f3dd.html
https://www.google.com/maps/@43.0430889,-76.1438985,2239m/data=!3m1!1e3
Summary:
Interstate 81 runs through the middle of Syracuse on a long bridge.
The bridge is 60 years old and needs replacement.
So the government will have to do one of the following:
$1,000,000,000 - tear down the bridge and shift traffic to Interstate 481 (which goes around the city)
$2,000,000,000 - tear down the bridge and build a new bridge in the same spot
$4.000,000,000 - tear down the bridge and build a tunnel
So, whatever they do, the government will have to spend a small fortune. And since it's an interstate highway, it's federal money and not state money.