It doesn't even take 8 story buildings to reach critical mass for high-density urban living. You can get high-density, highly-walkable urban neighborhoods at a

It doesn't even take 8 story buildings to reach critical mass for high-density urban living. You can get high-density, highly-walkable urban neighborhoods at as little as three stories. In fact it's better for walkability to have a whole neighborhood of three or four story buildings than to pack the equivalent housing into a few 8 story buildings with lots of empty space between them. Not that I expect the homeowners of Palo Alto would go for that, either.