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The Walkability Factor

by Lisa Rayle, Transportation Consultant


walkable grid – small block size // less walkable subdivision – large block size

In last week’s Times, Chris Leinberger argued that the apparent shift in homeowner preferences toward walkable, urban neighborhoods will spell decline for the far-flung auto-oriented suburbs.  Leinberger, a Brookings fellow and U-M professor, cites a recent survey finding that only 12% of future homebuyers will continue to want large houses in car-dependent suburbs.  Across the U.S., this shift, caused by changing demographics and homeowner preferences, would raise demand for housing in central cities and the denser suburbs.  Leinberger’s prediction may or may not become reality, but other evidence does suggest a demand for, and undersupply of, walkable, transit-friendly neighborhoods [1, 2].

If Leinberger is correct, what would this mean for metro Detroit? Which places might see increased demand?  This is a complex question and we can’t predict what will happen. But it’s interesting to look at one factor: walkability.  Leinberger suggests that neighborhoods in the most demand will be those that are walkable.

Which places are walkable?

Walkscore gives a quick indication of which neighborhoods are currently walkable.  The score is based on the number of destinations within walking distance; it doesn’t consider things like crime level or pleasantness of a street. Unfortunately, according to Walkscore only a few neighborhoods in metro Detroit receive a high score (e.g., Ferndale, downtown Pontiac).  In most of the region, it’s hard to go anywhere by foot.

Which places have the potential to be walkable?

Maybe some places with a low Walkscore are potentially walkable.  For this quick analysis, we will look at just one ingredient of walkability: street pattern.  Research studies find that street pattern correlates with pedestrian activity [3, 4]. In general, people walk more when streets are closer together, and a grid pattern is more conducive for walking.

Researchers often use block size to measure street pattern. Previous research suggests that a neighborhood is walkable for the average resident when blocks are no larger than 440 x 440 feet, or 4.4 acres [5].  Traditional street grids are usually smaller; in metro Detroit, the street grid produces average blocks of less than 2.7 acres.

 Average block size, one ingredient of walkability.  Blue indicates the most walkable street grid.

The map shows average block sizes in the Detroit region.  Blue indicates a walkable street grid, or something close to it. Yellow indicates streets too far apart to be walkable.  (Because this map is based on Census TIGER files, not street data, it is only an approximate estimate of block size.)

Block size is not all that matters. To be walkable, neighborhoods need destinations (schools, grocery stores, jobs) within walking distance. They need a certain density (usually at least 20-25 dwelling units per acre).  They need to be safe, with good sidewalks, lighting, and protection from traffic.  The above map does not include any of these factors. But the map does indicate, approximately, which areas have the underlying structure for walkability, upon which more convenient destinations and a better walking environment might be built.

[1] Levine, J. and L. Frank. Transportation and land-use preferences and residents’ neighborhood choices: the sufficiency of compact development in the Atlanta region.  Transportation, 2007; Vol. 34, Number 2, 255-274.

[2] Levine, J. and A. Inam.  A Choice-Based Rationale for Land Use and Transportation Alternatives Evidence from Boston and Atlanta.  Journal of Planning Education and Research, 2005; 24(3), p. 317-330.

[3] Saelens, B. and S. Handy. Built Environment Correlates of Walking: A Review.  Med Sci Sports Exerc. 2008 July; 40(7 Suppl): S550–S566.

[4] Saelens, B., J. Sallis, and L. Frank.  Environmental correlates of walking and cycling: Findings from the transportation, urban design, and planning literatures.  Annals of Behavioral Medicine, Volume 25, Number 2, 80-91.

[5] Moudon, A., C. Lee, A. Cheadle, C. Garvin, D. Johnson, T. Schmid, R. Weathers, L. Lin. Operational Definitions of Walkable Neighborhood: Theoretical and Empirical Insights. Journal of Physical Activity and Health, 2006; 3, Sppl 1, S99-S117.



6 responses to “The Walkability Factor”

  1. Todd Scott says:

    Excellent article and graphic. Walkability is not just about having some sidewalks.

    Walkscore does list scores for individual neighborhoods in Detroit. Some scores are higher than the scores for Michigan’s top cities.

    However, the Walkscores for Detroit neighborhoods along the River are incorrect. There is a known bug in their algorithm. Fixing that bug would boost Detroit’s overall walk score, but by how much, no one probably knows.

  2. P Becker says:

    Another big issue is the ability to cross major streets. Where I live, in northwest Southfield, it is impossible for a pedestrian to cross Northwestern Highway. It’s very difficult even at intersections with lights. This greatly reduces walkability even if the distances are easily managable.

  3. Shawn Reed says:

    I enjoyed this article; I think on a side note that places like Downtown Detroit and Midtown Detroit have a walkability that will be growing exponentially and the new “URBAN SUBURB” if there were such a thing will be places like the University District; you have parks within the subdivisions, restaurants, bars, schools, bus routes, diners, retail, produce, etc. etc. It’s obvious that the more things change the more they stay the same; the University District was built originally as a outlier neighborhood that would serve and cater to a suburban crowd. We have some really nice houses for sale in this area as well, some are 6 bedroom houses with land contracts available. Another great Detroit neighborhood is Rosedale Park, we also have houses in this neighborhood for sale via land contract. Go to our website and check us out! Thanks again D3 for the update on the Walk-O-Meter 😉

    Shawn Reed
    Marketing @ Prime Financial Plus Realty
    Detroit Land Contracts and More!

  4. Ken Firestone says:

    Two things.

    First, Walkscore is a wonderful tool for getting a rough approximation of walkability. If you use their beta StreetSmart Walkscore you will get the distances to amenities calculated along the street network, instead with a straight line distance. Often areas with good walkability do better, and poor walkability do worse with the StreetSmart version. (Its down towards the bottom of the results page)

    From my tourist visit last summer, I would guess that Midtown, Eastern Market and Mexican Town are quite walkable with good amenities.

    Second, from what I can tell from Google Earth, Detroit’s block lengths are “all over the place.” I measured a wide range of lengths.

  5. Ken Firestone says:

    One more Walkscore flaw. The database of amenities is often inaccurate, with some important things left out, and some bogus things included.

  6. Brian Vosburg says:

    I think one of the biggest missing pieces from Walkscore for the Detroit Metro area is the fact that none of the transit agencies provide their data in an open source format that Walkscore can use. So this is a major piece of walkability missing from all neighborhoods for the region which lowers our competitiveness to other regions of the country.

    Walkscore isn’t perfect, but it would also be nearly impossible for them to factor every variable in their algorithm. I think it is a useful tool for getting an approximation and good idea of the walkability of a neighborhood versus other areas.