Time, that is the time it takes to travel to a job, determines where people focus on in their search for a place to live. Thus a city like New York City has it’s own CBD (Central Business Districts) of Midtown and Downtown, with extensions on the upper East/West Sides and infill throughout, along with growing CBD developments along the river banks of the Hudson and East Rivers, especially with regards to Newark, NJ and Downtown Brooklyn, NY.
When it comes to choices for a residence, there is a curve of acceptable ‘time to commute’ for a particular job. Those on the outskirts of this curve might travel 2 or 3 hours each way, not because they want to but only as a necessary evil in their life to pursue their own interest and priorities. This is why the current commuter system fails, in that providing express service is just not enough to harness the potential of land just beyond the more acceptable half-hour commute, and why there needs to be ‘super express’ service to new core areas to help increase housing and opportunities while providing the ‘time connection’ people demand for their daily lives.