Most of our highways were started in the 50's and finished in the 70's with little expansion other than widening of the freeways. But one thing that could reduce the strain on the roads that no one seems to want to do... Expand the rail system. It's stable, has far fewer accidents than the road ways and pound for pound of cargo, is cheaps. And leading the way on environmental consciousness, they were one of the first industries to embrace hybrid technology, as all the locomotives are diesel electric hybrids.
Actually one thing I wish was more common with railways (I've only seen this in Alaska) is the ability to take the train with your car. You drive your vehicle on to a flatbed and then ride in one of the train cars. I would love this on my trips to Portland. Let Amtrak do the driving, then I have transportation once I get there. Sort of like how you can take a ferry from Bellingham, WA clear up to Skagway, Ak (with a few transfers).
One final comment on the bridge collapse. Why is everyone panicking about their local steen and cement bridges. Let's wait till we actually know what caused the collapse, then panic as needed.