I've been thinking about this idea over the past few months. My main thought is whether it passes muster in terms of economics. Revenue can be estimated as a mu

I've been thinking about this idea over the past few months. My main thought is whether it passes muster in terms of economics. Revenue can be estimated as a multiple, say, FedEx or UPS revenue. Maybe it would be 2-5x of whatever those do now, to account for the increased convenience. Do you have any rough ideas on what the cost would be? Also, another big issue is permitting. Which govt bodies would have to issue a permit to allow underground tunnels? Eg. I if I want to build some tunnels under Palo Alto, who has to approve it?