It's also important to understand the reason you can't have both, in the US, is political. Infrastructure spending in the US is currently below depreciation (http://blogs.wsj.com/washwire/2015/03/10/spending-on-our-cru...) so we aren't building mass transit at a rate that meets growing demand. Rich, mobile people buy up property in cities and along transit lines. If we invested in transit we could make a lot of underused housing useful.
It's also important to understand the reason you can't have both, in the US, is political. Infrastructure spending in the US is currently below depreciation (http://blogs.wsj.com/washwire/2015/03/10/spending-on-our-cru...) so we aren't building mass transit at a rate that meets growing demand. Rich, mobile people buy up property in cities and along transit lines. If we invested in transit we could make a lot of underused housing useful.