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Houston’s transit deserts

From the Kinder Institute’s Urban Edge blog:

HoustonMetro

A new study suggests that despite METRO’s launch of several highly-touted and publicized improvements, the agency is still struggling to address the needs of some communities that depend heavily on transit.

With operations beginning on METRO’s two new light rail lines and the reimagined bus system set to begin service in August 2015, the Houston region’s transit system is undergoing drastic changes.

There is no denying the merits of these new elements. On the whole, the new rail lines and the streamlined bus system will benefit many riders. The agency said that its bus system changes will double the number of potential riders who live within a half-mile of a frequent bus route to 1 million people. Meanwhile, the new light rails are providing faster, consistent service to two areas of town with high transit demand.

But, according to researchers at the University of Texas at Austin who have mapped what the changes mean for Houstonians’ access to transit, the results of the new systems offer more of a mixed bag.

Junfeng Jiao, an assistant professor of community and regional planning at UT-Austin, and Aaron Nichols, a graduate student in the same department, have studied and mapped the “transit deserts” of major Texas cities.

Their concept is adapted from the more widely-known idea of food deserts, or areas where residents lack access to fresh, nutritious food. By tracking transit deserts,

Jiao and Nichols can highlight the parts of cities that have greater demand for transit than supply.

The researchers released their findings for Austin, Dallas, Fort Worth, Houston, San Antonio in January.

To find out where the gaps in transit service exist, Jiao and Nichols collected two types of information about every census block group in a city: the transit demand and transit supply.

Transit demand is based on the percentage of people in an area that depend on public transit. Researchers arrived at that figure by subtracting the number of cars at a household from the number of eligible drivers living there and extrapolating it across the wider area. From that, the researchers determined the percentage of transit dependent people per acre.

They calculated transit supply by determining the number of transit stops and routes within each block group, as well as the frequency of transit service. They also considered the length of sidewalks, bike routes and low-speed roads as well as the density of intersections. The numbers were aggregated into a transit-supply per acre measurement.

Transit demand was then subtracted from transit supply. If the number is negative, the area is considered a transit desert.

The researchers acknowledge that the approach isn’t perfect. The number of cars per household is certainly not the sole factor that determines use of transit. For example, a household of five in which all members are over the age of 16 is unlikely to own five cars. By the study’s mechanisms, such a household would be considered transit dependent. In reality, though, this car-to-person gap does not automatically make a household transit dependent. Indeed a household might get along fine with three or even two family vehicles.

Despite this shortcoming, as a basic measure, the transit gap analysis offers a baseline for isolating transit-needy areas, evaluating existing service and helping planners and policymakers direct future transit investment to places that desperately need it.

The study is here. It was done using the existing bus map, not the new one that is coming in August, and only counts on rail line for Houston. The Urban Edge blog notes that the authors did produce an updated map for the (still being tweaked) reimagined bus lines, though for some reason they still didn’t account for the Harrisburg and Southeast rail lines. I’m not sure where they got that map, but it’s included in the blog post, and it does clearly show the effect of the new bus lines in that there’s far less oversupply of transit in the downtown area.

One key factor of this study is that it wasn’t just about where transit stops are. From their “Conclusions and Limitations” section at the end:

This main difference between this study and previous studies is that more emphasis was placed on access to public transportation, and not just the actual transit service. Factors that are typically associated with walkable landscapes, such as small block lengths and low speed roads were taken into consideration for transit supply. Essentially every transit trip is going to begin and end with walking. If someone is not willing, or unable to walk to or from a transit stop, then a transit trip will not likely be made. This is why the physical characteristics of the built environment that might contribute to or discourage walkability are vitally important when considering access to or from a transit stop at the beginning or end of a transit trip.

Total sidewalk length for each Texas city studied was one of the data points they used. That figure is apparently unknown for Houston, which may add some uncertainty to the results for our fair city. Better and more ubiquitous sidewalks – a point made by some at the latest system reimagining public meetings – would make transit more available, with an accompanying boost to ridership.

A few other thoughts…

– The maps for Houston are literally for Houston – there are big blank spaces where Bellaire and West U would be. I find that odd, since they (and many other small cities withing Houston’s borders) are also served by Metro. I doubt there are any transit-deficient areas within them, but still. It would have been nice to see a more filled-in map.

– Another improvement I’d like to see would be more detail in the data itself, so that one can tell which factor or factors led a particular area to be transit-deficient. Was it a lower rate of auto ownership for over-16 household residents, a lack of sidewalks, distance from the nearest bus stop, something else? Just looking at these maps, I have no idea what policy prescription if any might improve matters.

– Comparing the present and future gap maps for Houston, you can see how system reimagining will benefit outlying areas in the west, southeast, and northeast. The bulk of the areas with the largest deficiencies are in the southwest in both maps, though it’s a little better with the new bus routes. Again, it would be nice to know more about the specifics. I will note that one place named on the list of five most deficient areas is Gulfton, which would be on the western end of the Universities Line, if we ever do build it. Another reason to hope that the Culberson peace accord bears fruit.

– If these researchers would like to be more ambitious, I suggest expanding the study to something more like the Houston metro area. You don’t need to go full ten-county HGAC region, but including Montgomery, Fort Bend, Brazoria, and Galveston Counties in addition to all of Harris would give a much more complete picture of how people in greater Houston can get around. I would recommend including household income as a factor, as the authors have suggested they might in the future, as otherwise there would likely be a large transit gap in and around the Woodlands, when in reality you have a bunch of people who only ever drive. Doing this might also help pinpoint holes in connectivity between disparate transit systems and how many people are affected by them. May as well get a regional planning benefit out of this, right?

Anyway, those are my thoughts. What are yours? Link via Gray Matters.

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