I was bored this evening so I decided to Google street-view the downtowns of a few cities. The one thing that stood out was that cities w/ active street scenes and numerous pedestrians did not have many parking lots while those that appeared desolate and barren had parking lots everywhere.

For instance, compare the downtowns of the these similarly-sized [[population) cities:

Chicago: http://maps.google.com/maps?q=Chicag...2,94.62,,0,4.3
&
Houston: http://maps.google.com/maps?q=Housto...216.83,,0,4.23

*To be clear, the most urban street in downtown Houston seems to be Main Street, which also happens to be served by light rail. Even so, it does not appear very urban because the rest of city is comprised of poorly-designed office towers and parking lots.

Philly: http://maps.google.com/maps?q=Philad...,187.71,,0,3.6
&
Phoenix: http://maps.google.com/maps?q=Phoeni...276.91,,0,5.61

After looking at Houston and Phoenix, I was quite proud of downtown Detroit. Our street scene is seemingly more active than Houston's, which has more than 3x the population. But, Detroit could surpass many cities in terms of pedestrian activity if developers in Detroit started to create infill.

Detroit has a significant advantage over newer cities in that the majority of our architecture, including many recent buildings, abuts the sidewalk with first-floor retail. If you look at Houston, there is essentially nothing urban about it. Houston is more akin to Southfield- a suburban office park on a steroids- than it is a true urban environment.

In fact, virtually all of the sunbelt cities, with the exception of downtown Dallas' historic district, are designed completely around the automobile. There is virtually no retail, residential is scarce, buildings are very far apart, and there are parking lots galore. All of their buildings are set back from the sidewalk and are fortress-like. Those cities really can't improve their urban street-scape without bulldozing and starting from scratch. Detroit simply needs to not mess up future developments and make parking a secondary or tertiary consideration. The city also needs to push developers to design pedestrian friendly buildings. Let's keep it dense.

So, all of that leads up to my original question: How long do you think it will take before areas affected by light rail begin to develop from parking lots into buildings? Are there examples from other cities that we can look to for guesstimates?