The key to successfully reducing automobile dependency and enabling transit ridership is knowing where the people are. Houston Tomorrow has been working on a set of maps showing this information.
In order to determine where transit stations might be most useful in the existing urban fabric, researchers Peter Newman & Jeffrey Kenworthy published in the journal Opolis a paper called “Urban Design to Reduce Automobile
Dependence,” The paper proposes adding residential population and jobs in cities and regions to determine a set of data that point toward density of people gathered in a place.
In the Houston region, a map showing these densities, based on 2005 data from our Metropolitan Planning Organization, looks like the image at left. It is very abstract, but it’s easy to read and the first outlines of the transit network are obvious. In fact, each of darkest areas has more jobs than downtown San Diego, or Miami, or a lot of other cities. These areas are the low-hanging fruit. More people go to these places than any other places in the region. They need to be connected.
The image at left shows the nodes at three levels of intensity, with the four largest nodes connected by a transit line. Without considerations of alignments or technologies, this line is the fundamental connectivity that’s most useful first. It gives the biggest bang for the buck, because the distances are short (a total of around 9 miles) and the activity is very intense, with hundreds of thousands of potential transit riders. (This does not include the additional value of the nodes as attractors to all the amenities they contain.)
The next tier of intensity is also obvious. There may be other ways to accomplish the next step, but the one at left below pops quickly to mind. With the exception of the long purple line to the southeast, going to Clear Lake, this isn’t a lot of miles. A very large number of people would be connected to the amenities available in such a system, which now has 15 high-activity nodes. Access to the system occurs at several points around the region, so car access to transit can happen easily at the extremities.
The next tier is centers that can support less frequent and perhaps less expensive transit service. One configuration of strategies is shown at left above, but obviously there are more ways to make connections. This system in Houston would have about 100 nodes, and they would be the top activity centers in the region.
In such a system, suburban commuter access to transit happens in many places. The extent of suburban population is seen in the top image, which shows the system in the context of the existing suburban fabric, designated by yellow shades.