One odd thing is the claim that it's just as cheap to bore a much larger tunnel. Yet no one is bidding a much larger tunnel boring price anywhere close for either the short Las Vegas tunnel or the much longer Chicago one.
It is not odd i think it is a thinly disguised lie. If it was serious it would've done a point by point rebuttal of Elon's proposals and why he think he can reduce the cost more than 10x for same capacity (capacity is the operative word).
At the very least it could've shown cost calculations for these tunnels. If they are as attractive as portrayed we would've had many more of them.
A detailed rebuttal of musks boring ideas is clearly not the point of the article. But those articles for exist, for example this one (which includes a citation that cost may scale linearly with diameter): https://pedestrianobservations.com/2017/12/15/elon-musks-ide...
Except that in tunnel boring the circumference is not that relevant, it's the surface area of the cross section of your tunnel. In the first instance that's 113.1 square feet, in the second it's 452.4. Every time the radius doubles, the surface area quadruples.
The perfect tunnel transports people horizontally in a very narrow tube.
Your forgetting, I'm talking about either two lanes of traffic in one tunnel or one lane of traffic in two tunnels.
First order analysis says there is no saving by using two tunnels instead of one. When you consider 4 one lane tunnels vs one tunnel with four lanes of tunnels, the four tunnel solution is worse.
