It's my understanding the first tunnel plans were for a six-lane tunnel. I have not seen the elevation/depth info on the tunnel, but even at 200f, you just need a longer ramp to ascend.

But you have to build that subterranean ramp. The tunnel cost billions already without the ramp, how much more would it cost with that added complexity? There will still be surface streets where the viaduct is located.

I'm not a transit engineer but I do think this is one of the drawbacks in the kind of radical democracy we push in Washington. Everything goes up to a public vote, even things the public can't really fully be experts on.