Map of the Day: Average Jobs/Population Density Along SWLRT

With yesterday’s announcement that the price tag for the proposed Southwest LRT line (or “Green Line Extension” if you prefer) has jumped to $2 billion, there’s been a lot of chatter both inside and outside of Streets.MN about what this holds for the project.

Some have said the corridor should be dropped as it was poorly conceived. Others are taking this as an indication that the Alternative 3A (Kenilworth corridor) vs 3C (Uptown) debate should be revisited. Many top officials (including Governor Dayton and Metropolitan Council Chair Adam Duininck) have suggested that we take a step back and review the project. Meanwhile, Nick Magrino curtly asks this morning just what should we be fighting for?”.

Whether the project continues as proposed or changes are made, there is some validity in having some sort of transit line along the corridor, as this map shows:

Average jobs+population density per acre along the Southwest LRT corridor.  Map by the author, with background data from the US Census Bureau." width="500" height="386" class="size-medium wp-image-52959" /> Average jobs+population density per acre along the Southwest LRT corridor.  Map by the author, with background data from the US Census Bureau.

Average jobs+population density per acre along the Southwest LRT corridor. Map by the author, with background data from the US Census Bureau.” width=”500″ height=”386″ class=”size-medium wp-image-52959″ /> Average jobs+population density per acre along the Southwest LRT corridor. Map by the author, with background data from the US Census Bureau.

This map shows average jobs+population density per acre along the Southwest LRT corridor. Population data is from the 2010 Census, while jobs data is also from the U.S. Census bureau and is from a database that shows numbers of jobs per census block, with both datasets covering Hennepin County. This data was rasterized via a kernal density scheme and combined to show the average jobs plus population per acre.

Several studies going back over four decades (dating back to Pushkarev and Zupan in 1977) have looked at the relationship between density and transit. What Pushkarev and Zupan found is that, generally, an average of 5 jobs/population per acre is enough to support basic bus service, with higher levels of density able to support higher levels (and modes) of transit. As you can see on the map, the proposed Southwest corridor generally follows a swath where the average density is above 10 per acre, with nodes of higher density near Hwy 100, Opus/Bren Rd, and near Eden Prairie Center.

While people will continue to debate 3A vs 3C vs something else, or the high cost of the project, this density map shows that some sort of transit line along the general corridor would be worthwhile. If anything, instead of being curtailed to the Southwest Transit Center or Hopkins, it could even be extended further to Dell Rd and the cluster of jobs located there.


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11 Responses to Map of the Day: Average Jobs/Population Density Along SWLRT

  1. Alex April 28, 2015 at 10:17 am #

    Thanks for the map, Froggie. It’s important to get information out there that shows young, white, affluent urbanists that there might be a value to this line even if it doesn’t go to very many expensive restaurants and bars that they like to frequent. Less snidely, it shows that mixing uses is an important contribution to the transitability of an area, since the residential areas shown in yellow in St Louis Park and Hopkins are comparable in solely residential densities to the areas shown in green in Minneapolis neighborhoods like Lyndale and Central. I’d be curious to see a this map for the existing Green & Blue lines, as will as the Blue extension.

    • Adam Froehlig
      Adam Froehlig April 28, 2015 at 10:23 am #

      Future attraction: a map showing all of Hennepin County. Alas, I don’t have block-level data for other counties yet.

      • Sean Hayford Oleary
        Sean Hayford Oleary April 28, 2015 at 11:33 am #

        I look forward to this.

        Not the point at all of this post, but question: how is Normandale Lake Office Park — a fairly dense cluster of 15-25 story office buildings — not showing up here at all? Should be SW corner of 494/5 and Normandale Rd, but it’s just showing up as part of the yellow to orange zones.

        Also curious if there are other dark green centers outside downtown. I see a little blob in the Southdale District. I’d also wonder about Abbott Northwestern/Midtown Exchange area and MOA area.

        • Adam Froehlig
          Adam Froehlig April 29, 2015 at 6:47 pm #

          My numbers are showing a total of over 3000 jobs in that quadrant of the 494/Normandale interchange. Given the overall acreage of those properties, that comes to an average in the low 20s per acre. If I were to guess why it’s showing up so low, it may be the base data being at the census-block level (best I could find for jobs), or the values being averaged with the low-value wetlands to the south and west, or possibly an artifact of the methodology I used to create the graphic (which I believe explains why the MSP airport area shows up almost completely as less than 5 jobs per acre).

      • Will Sutton April 30, 2015 at 3:23 pm #

        This is an ingenious analysis. I’m just curious, where did you come across the data set that shows the number of jobs per census block? I’m really interested in running this analysis on my own but I cannot find any employment related census data beyond the block group.

    • Adam Miller
      Adam Miller April 28, 2015 at 10:55 am #

      Not exactly the same data but MinnPost did interesting visualizations of who lives on the Green Line: https://www.minnpost.com/data/2014/06/who-lives-green-line

  2. Alex Cecchini
    Alex Cecchini April 28, 2015 at 10:54 am #

    I can’t help but look at that map and think the Green Line should extend to the West End then 169/55 area, while a SW route should definitely not skip Uptown, and interline with other services through downtown as a N-S route.

    Also, it would be interesting to see this map with the color scales as equal ranges. Gray/orange/yellow are 5 person/job per acre increments, while the greens hop 15 and 20 each. There’s probably some nuance in seeing the middle densities (above regular bus service but below heavy rail) a bit more granular.

  3. David Markle
    David Markle April 28, 2015 at 12:06 pm #

    Hey, another great job, so far, by our unelected, unaccountable, unresponsive Met Council, huh?.

    • Peter Bajurny April 28, 2015 at 1:13 pm #

      I often use Peter Wagneus’ classic quote in reference to this project:
      “There are folks who are extraordinarily invested in validating the process that has brought us to this point.”

      But I see yet another David Markle comment and it makes me think…
      “There are folks who are extraordinarily invested in invalidating the process that has brought us to this point.”

      I get it, you’re buttmad that we don’t run LRT down freeways, even though literally nobody agrees with you.

      But by all means, banging that drum.

  4. Nick Magrino
    Nick Magrino April 28, 2015 at 12:30 pm #

    I would point out that density doesn’t cover the entire issue, land use is just as important if not more so.

    Aside from tens of people in Harrison who may opt to get a job in Eden Prairie within walking distance of the line, who does this actually benefit on the Northside? Are we building this for people who are going to take a fifty minute, two seat transit ride from the Hawthorne neighborhood to Eden Prairie and then walk a half mile along a stroad to entry level jobs near Eden Prairie Center? Do we think that people on the Northside with well-paid IT jobs in the Golden Triangle are going to not own cars and take advantage of the lack of congestion with a reverse commute (to an office park with free parking) that will take half as long as the train?

    What is going on?

    There are literally hundreds of thousands of existing jobs accessible by a single seat transit trip from West Broadway in half the time it would take someone to get to the Golden Triangle. Is adding a couple thousand more ten miles away going to make any difference?

    • Joe April 29, 2015 at 9:47 am #

      This has always been my question on this topic.