I think people are missing the strategic importance here. Tesla is going to be in the game of self driving cars. Once self driving cars happens, there is no longer going to be anyone who buys cars, they will simply hail a ride using the self-driving Telsa(Uber, Lift, Google) network. Soul-Crushing-Traffic is going to be optimized heavily, using certain algorithms and the inter connectivity of the cars. However, one HUGE advantage that Tesla cars are going to be able to have are these tunnels. I think this is of huge strategic importance, because they can reduce the cost for transportation across cities, because they don't have to deal with all the traffic. As discussed in plenty of places on hackernews, ride-hailing is going to be a commodity similar to the airline or ocean transport industry. It will be solely based on cost. If Tesla can make the cars at cost, owns the self-driving tech, are all electric with a huge network of free fuel, and have tunnels that allow you to bypass traffic then they will own the future transportation industry, while everyone else tries to catch up.