[tjansen]

I assume you're talking about US cities. Because IMHO most European cities are already far too dense. You can hardly see the sky.

[noelwelsh]

All cities with cars, and no, they aren't.

[mantas]

But if you make cities even densier, you'll have to restrict their height. People on the first floor still want sunlight for a reasonable time :) Meanwhile wide streets allow tall buildings..