POSTER SESSION AT THE 92ND ANNUAL MEETING OF THE TRANSPORTATION RESEARCH BOARD
Using 2010 Census and 2005 – 2009 American Community Survey data I studied the changing concentration of seniors and people with low incomes relative to their distance from the central business district in four major metropolitan areas. I selected cities with new light rail systems and tried to cover a cross-section of geographic regions across the lower 48 states. The cities I selected were Portland, Oregon, Salt Lake City, Utah, Dallas, Texas, and Charlotte, North Carolina. My paper was accepted for a poster session during this year’s annual meeting of the Transportation Research Board. The full poster is available at the link below.
The finding is consistent for all four metro regions: younger, more affluent populations are becoming more concentrated in close-in neighborhoods while older, poorer populations are becoming more concentrated in far-flung suburban neighborhoods. While this trend seems to make intuitive sense, the magnitude of change in several of the cities seemed to be orders of magnitude greater than we anticipated.
The table below shows percent change in location quotient (a concentration measure borrowed from economic base analysis) between 2000 and 2009. Age is broken into three sub-groups: 18 – 34, 35 – 64, and 65 and over. Income is measured as a ratio of household income relative to the poverty level. A ratio less than 1.0 indicates poverty. A ratio greater than 2.0 indicates an income that is two times the poverty level.
WHAT DOES THIS MEAN?
I’m not sure if I know quite what it means yet. One thing that is fairly clear is that seniors and people with low incomes – populations we know have a higher level of dependence on public transportation – are becoming more concentrated in areas that are difficult to serve with public transportation. This is an emerging issue that I believe will become an increasingly important challenge facing transportation planners for the foreseeable future. Additional research is needed to fully understand the magnitude of this shift, whether it is permanent or temporary, and how it will impact a wide range of public services including transportation, but also healthcare and housing.
I hope to use this blog to expand upon the research I presented at TRB. There are three specific ideas I have for expanding this research:
Include Distance from Transit Location Quotient Measures: When I originally ran the numbers I wanted to look at whether the presence of a major transit capital investment such as rail or streetcar would have an impact on concentrations of senior or low-income populations nearby the station areas. However, the transit infrastructure in these cities is so new it is difficult to determine if transit has had an impact during the period between the 2000 Census and the rolling estimates contained within the 2005 – 2009 American Community Survey.
Include additional metropolitan areas and a longer time-frame: By expanding this analysis to additional metropolitan areas and by including more recent ACS data, I hope to chart the extent and magnitude of the trend on a broader scale.
Include race, ethnicity and disability status: I hope that by including race, ethnicity, and disability status in the analysis we can begin to see whether the same trends witnessed for seniors and low income earners is also taking place for other populations as well.
If you know of data that would be useful in expanding this research, or have ideas for carrying it out, please leave a reply (link above).