While I think the Nurburgring is one of the worse thing to ever happen to automotive world, it still wouldn't stop me from driving to Vegas to take a run around the copy. I mean come on, you could come for the drive and stay for the cheap buffet, endless gambling and legal hookers! I honestly can't see how that would be bad
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I don't think it would be too hard to put the elevations in place either for the track, if there's one thing Nevada has it's an abundance of unused land. Getting the elevation changes would just take a bunch of guys with earth movers to get everything in place. We've done more complicated things with our everyday roads. The hardest part of this whole endeavor is being able to secure the abundant from whoever owns it, most likely the federal government. Also conducting the environmental impact study wouldn't be easy either since something that big is going to end causing issues for something.
They could easily turn the whole thing into a complex of sorts too inside the track area. Hotels, casinos, airport, man-made lakes, whatever you could think of, remember this is Vegas, anything is possible.
As for racing cars in the heat, doesn't Bahrain have a motorsports complex? Along with the Dubai? It's just as hot, if not hotter there and F1 cars seems to manage.
McLaren brings up a good point about the fatality and incident rate though, Americans have a different driving style and there would probably be more incidents than in Germany. But I guess it wouldn't be anymore dangerous than a standard track day somewhere.