Population Density and Job Density

[jeisenbe]

I wasted my Sunday making a Google-based map of Los Angeles County population density:
maps.google.com/maps/ms?ie=UTF8&hl=en&oe=UTF8&start=0&num=200&msa=0&msid=102764232639575421873.00047bbd63b18dd455fce&ll=34.056499,-118.29855&spn=0.076656,0.154324&t=p&z=13

For comparision, here is a Metro Rail / BRT system overlay (with Expo and Gold Line extentions): maps.google.com/maps/ms?ie=UTF8&hl=en&oe=UTF8&start=0&num=200&msa=0&msid=102764232639575421873.00046b0a527ac3df4da27&ll=34.029331,-118.225937&spn=0.306721,0.617294&z=11
(Add it to "My Maps" and then open up the two maps together to compare). The Gold Line extension is in a low-density area...

My source was this US Census map: upload.wikimedia.org/wikipedia/commons/e/e5/LACountyPopDensity.png

Unfortunately the census maps are based on rather large census tracts and is rather hard to read visually. I have seen maps of "block groups" before (smaller census units) but these are also messy. I tried to fit the lines to the built environment (based the the satellite maps; more apartment buildings = higher population density), and I also added in some areas that are industrial to explain the large gaps in population. The second page also shows job / shopping / entertainment centers, the other half of the transit equation. These sometimes also explain gaps in residential population density (downtown Santa Monica, Long Beach and Los Angeles, for example), but would not fit on the first page!

For employment density, see this map:
latimesblogs.latimes.com/.shared/image.html?/photos/uncategorized/2008/07/14/2006density.jpg
Sorry it is low resolution. I would love a large copy, if anyone knows of one.

There is also a Metro projection for job density in 2030:
latimesblogs.latimes.com/.shared/image.html?/photos/uncategorized/2008/07/14/employmentmap.jpg

I think these maps show the challenges we face in planning a good transit system, considering the low population density and spread out job centers in most of the County. Many areas (<10k) are hard for bus service to support, and others (25 to 35k) merit Light Rail but may not be dense enough to justify metrorail (subway or elevated heavy rail)

However, Koreatown, Westlake and Downtown are growing and have clearly benefited from the Red Line. If we are able to change zoning and development standards to allow more high-density areas for jobs and homes, with less room for cars (parking and driving), we could get many more areas dense enough to merit subways or grade-separated light rail. If the planning changes are made in advance, I think it would make sense to build rail for the city we want in the future rather than the suburban sprawl (<10k) and medium density (10-35) we have now in most of the county.

Also, these maps show that Long Beach deserves a 7th street subway!

[James Fujita]

I almost fell off my chair when you said that the Gold Line extension was low-density!

Then I realized you meant Foothill, not Eastside Do try to be careful when describing "extensions"

Nice maps, nonetheless.

[spokker]

Population densities matter, but doesn't it matter how many total people live in a certain area? There are places with crazy high population densities of 25,000 people per square mile. But then you realize the city is only one square mile.

I mean, if we look at population densities, we should be building a subway through Maywood. But Maywood is obviously not getting a subway stop.

[jeisenbe]

Spokker, yes, we SHOULD be building rail thru Maywood, though with density around 25 to 35k, it may not deserve grade seperations at current density. Remember, the Red and Purple lines go through areas with density of 35 to 60k or more.

In fact, the West Santa Ana Branch Corridor, which is on the second half of the transit projects according to the Metro 2009 LRTP (long range plan) but not funded by Measure R (as of 2009, at least), would go down thru the edge of Maywood, South Gate, Huntington Park, and through the center of Paramount and Belflower on the way the Cerritos and Artesia. The whole thing would not be completed until after 2035, based on present priorities:
maps.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=102764232639575421873.00047bd8878d16c343cab&ll=33.973545,-118.101654&spn=0.308062,0.617294&z=11

I also mapped an Atlantic Blvd rail line in the link above. Damien Goodmon supports that route, but I don't know if it is on Metro's current plans. Atlantic Blvd has the advantage of serving Maywood and Bell much better, though it still goes thru low-density Cundhay (an industrial area?) on the way to East Compton and North Long Beach. Damien suggested turning the line west at around Artesia, but I believe Atlantic Blvd thru Long Beach could support light rail all the way to Downtown. In the meantime, we really need exclusive bus lines and limited-stop routes (i.e. BRT) for Atlantic, all the way from the SGV to Long Beach.

[jeisenbe]

Spokker's first question asked whether the "total population" matters.

Well sure, it's the total population within a certain distance of each station that determines ridership, among other things. People within 2 miles either side might take the line for long-distance trips, after transferring from bus or bike (or car?); this is a commuter-rail model, suitable for Metrolink or even light rail with very wide station spacing.

However, most people walk to transit if possible. Since 1/4 mile is a 5 minute walk, density within that radius is most important, though many people (such as myself) will walk 1/2 mile or even a little more to get to reliable/fast/frequent transit service, especially for longer trips. So the population and job density within 1/2 mile of the line (or more realistically, within a 1/2 mile of stations), a 10 minute walk, is key.

That's why the Subway works; it has >60k pop density in Koreatown / Westlake and >200k jobs/mile in Downtown, and the rest of the red line has >35k pop/mile within 1/2 mile of the stations all the way to Hollywood/Highland.

We need to plan the city for those sort of densities if we want a subway in a certain route.

For moderately dense areas, light rail like the Expo line can provide almost as much service as the subway (the max capacity will likely not be reached even with $20/gallon gas), but it doesn't make sense to bury the trains underground. There just aren't enough pedestrians on the streets around the rail line for that to be necessary. That's why even grade-separated regional rail lines (like the Long Island Railway or the Paris RER) are only subways through the historic center of the city, and are elevated or ground-level though the suburbs and even in newer dense centers built after the rail lines.

[bluelineshawn]

Nice map. I'm surprised to see so many dense places even if many of them are very small.

[jeisenbe]

Bluelineshaw, the biggest surprises to me were the super-dense spots in Baldwin Village near the Crenshaw district (Just south of MLK, between La Brea and Crenshaw), and the two blocks north of Rosecrans between Praire and Crenshaw in the city of Hawthorne. The surrounding areas are only about 15,000 per square mile, not much more than average, making these neighborhoods really stand out on the map:

Baldwin Village:
maps.google.com/maps/ms?oe=utf-8&client=firefox-a&ie=UTF8&hq=&hnear=Exposition+Blvd+%26+Arlington+Ave,+Los+Angeles,+CA+90018&gl=us&ei=Z5Q9S47tFIPiswO2uqnaDA&ved=0CAgQ8gEwAA&hl=en&msa=0&msid=102764232639575421873.00047bbd63b18dd455fce&ll=34.015246,-118.350306&spn=0.008395,0.013797&t=h&z=16&start=1

Hawthorne:
maps.google.com/maps?q=arlington+and+exposition,+los+angeles,+ca&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&hq=&hnear=Exposition+Blvd+%26+Arlington+Ave,+Los+Angeles,+CA+90018&gl=us&ei=Z5Q9S47tFIPiswO2uqnaDA&sa=X&oi=geocode_result&ct=title&resnum=1&ved=0CAgQ8gEwAA

Both these areas are less than 1/2 square mile in area but have >35,000 residents per square mile, due to being mainly 2 to 3 story apartment buildings, as you can see on the overhead or street views on Google. The FAR (floor-area-ratio) is no more than 1.0, not that high, yet the pop density is the same as Brooklyn or the Bronx; enough for a Subway or El if it were more than just one neighborhood.

Unfortunately, the planned Crenshaw / MLK station is a long walk from the densest part of Baldwin Village, and there are no current plans to serve the dense neighborhood in Hawthorne. Even the Get LA Moving plan only had a rail line down Hawthorne, no Praire or Crenshaw, south of Florence. Due to the low residential density, and lower job density, in the areas surrounding these two pockets, grade separalted transit, or even frequent service, is unlikely to be sustainable.

For the Crenshaw light rail to work well, it needs to get to Wilshire or all the way to Hollywood, and the neighborhoods along the line further south need to support new dense residential development and high-density job locations. Those courtyard apartments in Baldwin Village are only 2 stories. Allowing 4 story buildings (with courtyards and green space, but no surface parking lots) within 1/2 mile of stations would allow equally high density with plenty of green space, and taller commercial or mixed-use buildings could be allowed on Crenshaw Blvd itself. Then Damien Goodmon's grade-separation demands would make sense, and everyone would be happy!

[jejozwik]

found this website for census information. this is a much better visual then the google maps provided.
no offense, but you guys are no graphic designers!

www.socialexplorer.com/pub/maps/map3.aspx?g=0&mapi=SE0012&themei=767686.653420823.4556.048&l=-1799556.60410719&r=-1527716.92621451&t=4623797.67586874&b=4510660.59087912&rndi=1

[jeisenbe]

Thanks for the link.
I like having it in Google Maps as well, so it can be directly overlayed with streetview, satellite imaging, and fantasy maps. Also, one of the maps shows jobs data is from future projections, which is a little different, and not readily available from census data.

I also am disappointed that the highest population density shows on socialexplorer.com is ">15,000k" per sq mile. 15k per mile is just barely enough for an at-grade light rail line, while 60,000k per mile (as in Koreatown and Westlake, and perhaps parts of downtown Long Beach) demands a subway. The map I made has 10k as the lowest level distinction; below that density even bus service may be limited. But there is some benefit in seeing the difference between a place with 1000 people per mile (very low suburban density, nearly rural) and 9000 per mile (a denser suburb), which socialexplorer.com shows nicely, and that is more of the range of densities in the San Gabriel Valley or South Bay.

[jeisenbe]

Great new population density maps from Blogdowntown, and these are overlayed on a street map, with data down to the block level! Yeah!

LA County Population Density: blogdowntown.com/custom/census/county_density.html

(It is expressed in a weird way, by "square feet per person", which doesn't make any sense to me when I try to change it to population per square mile, but it appears to work as a relative comparison)

LA County Population Change, 2000 to 2010
blogdowntown.com/custom/census/county.html

All of the maps:
blogdowntown.com/custom/census/

[matthewb]

Very nice USC masters thesis on LAs urban core. This is where we need to have rail connections ASAP:
www-scf.usc.edu/~skrueger/Thesis/Krueger_2012_MS_GIST_Thesis_Final.pdf

And for those who don't want to download a big PDF, here's a quick article with a map: la.curbed.com/archives/2012/11/usc_geography_student_finds_la_has_a_very_long_urban_center.php