We have a bridge replacement project going on. They erected a third temporary span between the two original bridges, and the process is that they tear down one bridge at a time and replace it, while diverting all the traffic onto the third, temporary bridge, which they then tear down. This is all neccessary, because the original bridges are circa the depression, and were built over a huge ravine with a river in the bottom, and are a single, VERY long span, with no pilings whatsoever. They're actually bowing. The new bridges are going to be 3 spans each and wider for future growth.
But anyway, the construction zone is TERRIBLY annoying. They installed the temporary so well (because it'll take so long to finish each bridge) that the temporary roadway and the pavement on the bridge is actually the same quality of a permanent highway here in MD. It's just as wide as normal, the only reason the speed limit drops to 45 from 65 is the general work zone safety, which is also relatively moot because the entire work zone is walled off with double-height jersey wall. Also, the manufacturer's recommended speed on the prefab bridge is 45mph. You can actually see the frustration as drivers slow down to as slow as they're comfortable (55ish) on the approach, only to be told that they're still speeding by the RADAR sign (not a camera, fortunately), and then they brake as they approach the sign trying to make it go ever lower. It's f'ing painful.