Comment by desdiv

>Also, what is the point of those rails? Seems like self-driving cars would be much easier and require a lot less.

That was my first reaction as well. I think it might have to do with there being no way of expelling the exhaust gas. As long as even just 1% of the cars using the tunnel are fossil fuel powered their exhaust will poison the whole system (carbon monoxide can fuck you up at even just 50 PPM).

They could limit the tunnels to just self-driving electric cars though.