Also perhaps worth mentioning in Chicago is Lower Wacker Drive.

It's a split-level street, more-or-less with local traffic on the surface and with through traffic at the subterranean level. It's a quick way to get through the area.

And beneath parts of that that is an road I've heard referred to as Lower Lower Wacker. This is almost entirely the realm of delivery and service vehicles (except for a time in fairly recent years when those darned kids were using it for drag racing at night).

It's all crazy-expensive to build anything like underground local delivery rail and underground roadways.

(But the stuff at the surface is crazy-expensive, too, and often can't be expanded horizontally without demolition of the very buildings that it seeks to benefit.

But expanding down? Sometimes, yeah -- that can happen.)