[Qwertious]

Because car-based roads are so fucking noisy, we throw a ton of green space and front yards to mitigate it. Not to mention "sidewalks" are unnecessary when you can just walk in the centre of the street.

The size of a traditional road is about 6 metres wide or less (that's measured from the front wall of the building on one side, to the front wall of the building on the opposite side). In comparison, the same wall-to-wall measure of a car-centric suburban street comes out to, IIRC, 20-30 metres. That's 3-5x the cost in just land alone, let alone maintenance.

And yes, we will need some roads - about 20% or so, as arterial roads. But right now we're closer to 100%, and most of the throughput of arterial roads is tied up in one-occupant passenger vehicles rather than actually necessary cargo/tradie vehicles.