I always wondered if elevated biking lanes, especially in urban areas, would be far cheaper and safer than bike lanes intermingled with surface streets. Some high strength plastic that is lego-assembled and bolted to buildings. or maybe just suspended from cables between the skyscrapers.
I know everyone loves to hate, but the boring project would be great for things like this. Yes they are targeting auto tunnels, but with EV come a far easier range of mixed vehicle (scooter, ebike, moped, golf cart, side-by-side, atv, etc) use, without those noxious tailpipes that make tunnels problematic (yeah you still need air ventilation, but probably don't need complex systems for hoovering out carbon monoxide). The boring company demo is kind of stupid for full size cars... but for man-portable vehicles (aka a healthy human could lift it) it makes a lot more sense.
Although really I think this is still an urban compromise design. Really the influx car streets should be forced to be elevated or tunnels, and the entire surface area of cities are ebikes, scooters, and only heavily restricted permitted delivery trucks.
So while it is cool that they tunneled down the transport, what really needs to happen is that all car transport in urban areas is moved away from killing bikers and pedestrians.