[SomeCollegeBro]

> Besides the "normal" resistance to wind, if you want to build a sort of half-pipe covering a highway you need to consider the pressure induced from the inside by high-speed moving objects and the possibility to resist accidents (preventing an 18 wheeler from completely crash a - say - 100 m section of the half-pipe in case of an accident needs a rather sturdy structure).

I mean, aren't these issues already basically solved? I frequently drive through miles-long tunnels under Boston at 70mph.

[rtkwe]

A tunnel is already massively over specced for that because it's preventing the tons of soil/rock/building overhead from collapsing down. The forces for cars passing underneath is minuscule compared to that. For a hypothetical covered roadway you want something much cheaper and lighter so it's not mind numbingly expensive to build.