CategoryResearch/Study

Chicago has too many traffic signals

IMG_2496

People wait at a stop light on the first major ring road in the city center of Amsterdam. Photo: Northeastern University, Boston

I was flabbergasted to learn today that there are only 5,500 signalized intersections in all of the Netherlands. I was reading Mark’s blog “Bicycle Dutch” and he interviewed a city traffic signal engineer in Den Bosch, who described how different road users are prioritized at different times based on the complex programming. (Watch the video below.)

In Chicago there are more than 3,000 signalized intersections. And I believe this is way more than we need.

I understand more than the average person how traffic moves in each place and how it “works”. There is such a thing as too many traffic signals because at some point the signals (their proximity and their programming) start causing delays and conflicts.

Saying that traffic – of all kinds, bikes, trucks, buses, delivery vans, and personal vehicles – moves better in cities in the Netherlands than in Chicago is an understatement.

Aside from their impacts on traffic (which can be good in some situations, but aggravating existing problems in other places), signals are very expensive to purchase, install, and maintain.

In Chicago, an alderman (city councilor) can use part of their $1.3 million “menu” money annual allocation to purchase a traffic signal for $300,000. That’s money that won’t be used for transportation investments that reduce the number of severe traffic crashes as well as reduce congestion like bus lanes and protected bike lanes.

Let’s review

I compared their populations (about 17 million in the Netherlands and 2.7 million in Chicago) and saw that Chicago has a lot more traffic signals per person.

On Twitter, however, I was challenged to find the number of traffic signals per mile driven, not per capita.

So, I did, and I was surprised by the result.

This assumes I collected the right statistics, and converted the driving figures correctly.

The surprise: There are more passenger miles driven (known as VMT) in the Netherlands, per capita, than in Chicago. I actually can’t even get passenger miles driving in Chicago – I can only find “all miles” driven. And that includes trips on interstates that pass through Chicago but where the driver or passengers don’t stop in Chicago.

Here’s the analysis, though.

Driving

  • According to the OECD, there were 145,400 million kilometers driven on roads, for passenger transport, excluding bus coaches, in the Netherlands in 2013 (the latest year for which data was available in the Netherlands). That’s 145.4 billion kilometers. (Source, no permalink.)
  • According to the Illinois Department of Transportation, there were 11,150,109 thousand miles for all kinds of road transport, in Chicago in 2013. That’s 11.2 billion miles, which converts to 17.9 billion kilometers. (Source)

Population

  • In 2013, the Netherlands had 16,804,430 inhabitants (they had declared reaching 17,000,000 this year), according to the OECD.
  • In 2013, the City of Chicago had 2,706,101 inhabitants, according to the U.S. Census Bureau’s 2009-2013 ACS 5-year estimate.

Signals

Results!

  • The Netherlands has over 39 signalized intersections per billion kilometers traveled.
  • Chicago has over 167 signalized intersections per billion kilometers traveled.

The rate of change on city streets: USA versus the Netherlands

ThinkBike 2013

One of the people in this photo is Dutch. We’re on the Dearborn bike route installed downtown in 2012. The next downtown protected bike route was installed in 2015 serving a different area. However, the Dearborn bike route has become so popular that it’s size and design (t’s a narrow, two-way lane) are insufficient for the demand (who knew that bicycling in a city center would be so high in demand, especially on a protected course?) and there are no plans to build a complementary facility to improve the conditions.

My friend Mark wrote the following paragraph on his blog, BICYCLE DUTCH, relating the need to change a city and its streets to the way families change the contents of essential parts of their homes. In other words, cities and streets are like our living rooms and they must also change as we change.

Think about your living room, chances are you change it completely every 15 to 20 years. Because you need a wider sofa for the expanding family, or because you rightfully think that table has had its best years. Maybe the extra big seat for granddad is sadly not needed anymore. Of course, things can’t always be perfect: you have a budget to consider and it is not so easy to change the walls. Replacing things does give you the opportunity to correct earlier mistakes and to get the things which are more useful now. While you are at it, you can also match the colours and materials better again. Our cities are not so different from our living rooms. Just as families grow and later decrease in size again when the children leave the house, the modal share of the different types of traffic users changes over the years. These shifting modal shares warrant changes to the street design. So you may need some extra space where it was not necessary before, but if you see less and less of a certain type of traffic, its space can be reallocated to other road users.

What I really want to talk about is the rate of change in the Netherlands. I’ve visited Mark’s home in s’Hertogenbosh (Den Bosch), and we’ve walked around Utrecht.

One thing he told me, which is widely evident, is that the Netherlands is always renewing its streets. Or it has been for decades (maybe since World War II). They update street design standards regularly and streets that no longer meet these designs (or a few generations back) are updated to meet them.

Now, the two changes – updating the standards and updating the streets – don’t happen so gloriously hand in hand. Just like in the United States it takes a couple of years to come up with the right design.

The difference between our two countries is the regularity in updating the designs, and the regularity in updating streets.

I’ll lead with one example in Chicago and ask that you tell me about projects in your city that repair what’s long been a pain in the ass.

An intersection in the Wicker Park neighborhood got modern traffic signals, added crosswalk signals (there had never been any), and a stupid, sometimes dangerous little island removed. One of the four legs didn’t have a marked crosswalk. The state of Illinois chipped in most of the cost of the update – this was known at least four years before the construction actually happened.

When I wrote a blog post about the project for Grid Chicago in 2012, I found a photo from 1959 that showed the intersection in the same configuration. I also wrote in that post that the construction was delayed from 2012 to 2013. Well, it got built in 2014.

Milwaukee & Wood ca. 1959

Intersections like this – with difficult-to-see traffic signals that motorist routinely blow past, missing crosswalks, and curb ramps that aren’t accessible – persist across Chicago in the state they’ve been in for 55 or more years.

The “reconstructed bicycle route” that Mark discusses and illustrates in his blog post is known to have been updated at least once a decade. He wrote, “pictures from 1980, 1998 and 2015 show how one such T-junction was changed several times. The protected intersection went through some stages, but having learned by trial and error, the design we see now is one that fits the present ‘family’ best.”

Three books by well-known city transportation planners have all been published within months of each other. I read and reviewed Sam Schwartz’s “Street Smart”, and I’m reading Janette Sadik-Khan’s “Street Fight“. Gabe Klein’s “Startup City” is the third. All of them advocate for new designs to match the changing attitudes and needs cities have. Actually, the needs of the cities haven’t really changed, but our attitudes and policies – and the politics – around how to update cities has evolved.

I don’t know what can spur all of these seemingly minor (they’re no Belmont Flyover) infrastructural updates. I don’t think a lack of money is to blame. I think a lack of coordination, staffing, and planning ensures that outdated and unsafe designs remain on city streets.

P.S. The Netherlands “renewal” attitude isn’t limited to streets. The Dutch national railway infrastructure company “ProRail” (which is “private” but owned by the government) has been completely replacing all of the primary train stations. The Dutch have been rebuilding dikes and building flood control projects for decades, many under the common name “Delta Works”.

Here’s a photo in Nijmegen where the government was building a new, bypass canal that would ease a shipping route, create a controlled flood area, a new recreation area, but that would also displace homes.

Which places in Chicago get the most building permits?

View from the CTA green roof

The Merchandise Mart in the Near North Side community area ranks second place in locations receiving the most building permits.

Ed. note: I changed the title of this blog post because one interpretation of the original, “Where are the most building permits issued in Chicago?”, has the answer “City Hall”, the location of the issuer. My bad. 

Without regard to type or construction cost, the most building permits in the City of Chicago are issued at 11601 W Touhy Ave.

Where is that? It depends on which geocoder you use.

Two buildings at 11601 W Touhy Ave from Google Street View. The City of Chicago has issued thousands of building permits to this address, but the work is actually distributed across the O'Hare airport grounds. Google Maps and the Cook County parcel map places these buildings in Des Plaines.

Two buildings at 11601 W Touhy Ave from Google Street View. The City of Chicago has issued thousands of building permits to this address, but the work is actually distributed across the O’Hare airport grounds. Google Maps and the Cook County parcel map places these buildings in Des Plaines.

Google Maps puts it on this building that’s on a street called “Upper Express Drive” and in the city of Des Plaines, Illinois. But the City of Chicago wouldn’t issue building permits in another city.

Our own geocoder converts the geographic coordinates given in the city’s building permits database for these permits to the address “399 E Touhy Ave, Des Plaines, IL”. The Cook County parcel for the same location has the address “385 E Touhy Ave, Des Plaines, IL”.

Now where is this building?

It’s at O’Hare airport, and it’s one of a handful of addresses* the city’s buildings departments uses to denote permits issued to work at O’Hare. Since 2006 to Saturday, December 12, 2015, there’ve been 2,403 building permits issued here. The permits’ work descriptions indicate that a lot of the work occurs elsewhere on the airport grounds.

13 buildings have had more than 400 permits issued since 2006 to yesterday.

address community area count
11601 W Touhy Ave O’Hare

2403

222 W Merchandise Mart Plz Near North Side

802

141 W Jackson Blvd Loop

538

233 S Wacker Dr Loop

518

2301 S Lake Shore Dr Near South Side

516

30 S Wacker Dr Loop

510

5700 S Cicero Ave Garfield Ridge

495

500 W Madison St Near West Side

482

227 W Monroe St Loop

422

55 E Monroe St Loop

421

875 N Michigan Ave Near North Side

408

151 E Wacker Dr Loop

407

350 N Orleans St Near North Side

401

A pattern emerges: 10 of these 13 buildings are in the Central Business District and the other three are O’Hare airport, McCormick Place (2301 S Lake Shore Drive), and Midway airport (5700 S Cicero Ave).

The first location that’s outside the Central Business District and not one of the city’s airport or its convention center is at 1060 W Addison St – better known as Wrigley Field – in the Lake View community area with 321 building permits issued. It ranks #30. If you keep running down the list, the next most frequently issued location is 7601 S Cicero Ave – that’s the Ford City Mall and I think the city’s only sprawl-style indoor mall. It ranks #39 because it pulls monthly electric maintenance permits.

The Merchandise Mart’s position at #2 is notable because the majority of its permits are for small amounts of work: there is a lot of electrical rewiring done because of the frequent shows and exhibitions in the interior design materials “mall”.

The Mart sees other activity, though, including multi-million renovations for technology companies like Motorola Mobility and Braintree. The Mart also received a permit this year for a new $3 million staircase construction, part of its building-wide renovation project.

Rendering of new main (south) lobby staircase at the Merchandise Mart

This rendering shows a new grand staircase that will be built in the Merchandise Mart’s south lobby jutting from the side of the lobby that’s between the doors on the Chicago River side, and the reception desk and central elevator bank. A building permit issued this fall puts the construction cost at $3 million.

If you want to know more about building trends in Chicago, send me a message through the Chicago Cityscape website and I can put together a custom report for you.

* Other addresses I’ve noticed are:

  • 10000 N Bessie Coleman Dr
  • 10000 W Ohare St
  • 11600 W Touhy Ave
  • 11555 W Touhy Ave

Of these only the two Touhy Ave addresses are logical: O’Hare Street isn’t a real road, and 10000 N Bessie Coleman Dr is much further north than the northernmost point in Chicago.

A century old former radium extraction site in Bronzeville gets building permit

Map of the Carnotite Reduction Company site near Bronzeville

The Carnotite Reduction Company site near Bronzeville. Map: OpenStreetMap

A recently-issued building permit on 26th Street just east of King Drive in the Prairie Shores neighborhood of the Near South Side community area (near Bronzeville) caught my eye.

Installation of temporary wood poles and aerial cable, to powering air monitors, for the Carnotite Reduction Company site project

Carnotite wasn’t a word I’ve heard before, and “Carnotite Reduction Company” isn’t a business I’ve heard of before, either.

I searched Bing and found that 4 of the 5 results were about cleaning up a contaminated site, and one of the results was a letter in PDF form hosted on the Centers for Disease Control and Prevention website prepared by a scientist at the Illinois Department of Public Health.

The letter is 11 pages long and tells the story about Carnotite Reduction Company, which had a factory in 1915 on what’s now known as the Michael Reese Hospital site, the buildings of which have all been demolished.

The Carnotite Co. mainly produced radium, along with some uranium and vanadium as byproducts.

The Carnotite Co. owned and operated mines in Colorado and Utah. In 1919, it was one of four companies that mined 95% of the carnotite ore produced in Colorado. The U.S. dominated the world radium market until 1922, when Belgium began using pitchblende ore from the Belgian Congo. The pitchblende was 40 to 100 times more pure than carnotite, and by 1923, Belgian competition ended carnotite ore processing in the U.S.

This article from the “Chicago Chemical Bulletin” publication in 1917 linked on the United States Environmental Protection Agency’s website about the cleanup project describes carnotite ore and mining process. They’ve cataloged this site as EPA ID# ILN000510371.

Chicago Chemical Bulletin: 1917 article about the Carnotite Reduction Company

The letter describes where radioactive, contaminated soil was found during boring tests made within the last three years, and how it potentially got there. The factory was extracting radium there, for an exploding cancer research trend, until 1920.

The company, the EPA believes, may have disposed its waste into public infrastructure.

The US Environmental Protection Agency (USEPA) suspects that the Carnotite Co. may have sent this liquid waste into the sewer, floor drains, or reintroduced it into the process for further refining. Because streets in the area, including Inglehart Court, were abandoned during the redevelopment in the 1950s and 1960s, sewers running along those abandoned streets likely also were abandoned. Other options for liquid waste disposal commonly used at the time included streams or ditches (with Lake Michigan in the vicinity), waste ponds, dug wells, and dumping wastes on porous ground (such as the sand on-site).

When the City of Chicago was preparing the site in 2009 for a potential Olympic Village for its 2016 Olympic Games bid – buying the property for an insane amount of cash and then razing it all, while eventually losing the bid to Rio de Janeiro – conducted “Phase I and Phase II environmental investigations” but didn’t survey for radiological contamination and didn’t uncover an important survey from 30 years prior.

The Illinois Department of Public Health found radioactive contamination after a “radiological surface survey” of the Michael Reese hospital site in 1979.

The IDPH Division of Radiological Health concluded that the contamination did not pose an immediate health threat, but should be taken into account before any future construction. In 1979, IDPH did not notify USEPA about the contamination they found.

The Illinois Emergency Management Agency surveyed the site in August 2009 and found the contamination, alerted the EPA, and met with the City of Chicago to discuss remediation.

The letter details further testing by AECOM, a global transportation, infrastructure, and engineering company, the levels of contamination, and risk assessment. It appears that the contamination won’t be a danger to most people.

The Illinois Department of Public Health concludes that exposure at the Carnotite Co. site to the area with the greatest surface radium and uranium concentration for 20 minutes per day, five days per week, 250 days per week, for 50 years is not expected to harm people’s health. IDPH considers this to be a maximum likely exposure scenario, given current conditions at the site.

It notes that a change in land use – the site is currently occupied by vacant hardscape, tennis courts, a park, sidewalks, and grassy areas – “could increase exposure duration”, especially if housing was built here.

The City of Chicago applied for a license in 2013 to temporarily store radioactive material on site before shipping it to a disposal facility. The EPA last updated its website in April 2014 to say that it was considering this application.

Who are the top property owners in Cook County

235 West Van Buren Street

There are several hundred condo units in the building at 235 W Van Buren Street, and each unit is associated with multiple Property Index Numbers (PIN). Photo by Jeff Zoline.

Several people have used Chicago Cityscape to try and find who owns a property. Since I’ve got property tax data for 2,013,563 individually billed pieces of property in Cook County I can help them research that answer.

The problem, though, is that the data, from the Cook County combined property tax  website, only shows who receives the property tax bills – the recipient – who isn’t always the property’s owner.

The combined website is a great tool. Property value info comes from the Assessor’s office. Sales data comes from the Recorder of Deeds, which is another, separately elected, Cook County government agency. Finally, the Treasurer’s office, a third agency, also with a separately elected leader, sends the bills and collects the tax.

The following is a list of the top 100 (or so) “property tax bill recipients” in Cook County for the tax years 2010 to 2014, ranked by the number of associated Property Index Numbers.

Many PINs have changed recipients after being sold or divided, and the data only lists the recipient at its final tax year. A tax bill for Unit 1401 at 235 W Van Buren St was at one time sent to “235 VAN BUREN, CORP” (along with 934 other bills), but in 2011 the PIN was divided after the condo unit was sold.

Of the 100 names, DataMade’s new “probablepeople” name parsing Python script identified 13 as persons. It mistakenly identified eight names as “Person”, leaving five people in the top 100.

The actual number is closer to 90, arrived at by combining 5 names that seem to be the same (using OpenRefine’s clustering function) and removing 5 “to the current taxpayer” and empty names. You’ll notice “Altus” listed four times (they’re based in Phoenix) and Chicago Title Land Trust, which can help property owners remain private, listed twice (associated with 643 PINs).

[table id=2 /]

Not all demolition activity is alike on Chicago’s North and South Sides

According to building permit activity in the past 30 days there are more demolitions on the North Side than on the South Side, but most of those will have new buildings.

According to building permit activity in the past 30 days there are more demolitions on the North Side than on the South Side, but most of those will have new buildings. Map by Chicago Cityscapen using Mapbox satellite imagery.

I review the new permits each day on Chicago Cityscape, both in the list and map views, to get a sense of what’s being built around the city. This keeps me informed so I can tweet interesting permits, respond to people’s questions several times a week, and even help out on a Moxie tour of Motor Row and the Cermak Green Line station by mention new construction and renovation permits I’ve seen pop up nearby.

This week I was poking around the Demolitions Tracker and saw that, not unusually, there were a lot of houses being demolished on the South Side. So I checked out a 30-day view of demolitions in the full-screen map that shows the entire city.

While the North Side has more demolitions going on than the South Side, most of them are part of teardowns – the demolished buildings are getting replaced or allowing for expansion. Demolitions on the South Side are much less likely to have associated new construction projects than the North Side.

Tina Fassett Smith tweeted back:

Use Turf to perform GIS functions in a web browser

Turf's merge function joins invisible buffers around each Divvy station into a single, super buffer.

Turf’s merge function joins invisible buffers around each Divvy station into a single, super buffer –all client-side, in your web browser.

I’m leading the development of a website for Slow Roll Chicago that shows the distribution of bike lane infrastructure in Chicago relative to key and specific demographics to demonstrate if the investment has been equitable.

We’re using GitHub to store code, publish meeting notes, and host discussions with the issues tracker. Communication is done almost entirely in GitHub issues. I chose GitHub over Slack and Google Groups because:

  1. All of our research and code should be public and open source so it’s clear how we made our assumptions and came to our conclusions (“show your work”).
  2. Using git, GitHub, and version control is a desirable skill and more people should learn it; this project will help people apply that skill.
  3. There are no emails involved. I deplore using email for group communication.*

The website focuses on using empirical research, maps, geographic analysis to tell the story of bike lane distribution and requires processing this data using GIS functions. Normally the data would be transformed in a desktop GIS software like QGIS and then converted to a format that can be used in Leaflet, an open source web mapping library.

Relying on desktop software, though, slows down development of new ways to slice and dice geographic data, which, in our map, includes bike lanes, wards, Census tracts, Divvy stations, and grocery stores (so far). One would have to generate a new dataset if our goals or needs changed .

I’ve built maps for images and the web that way enough in the past and I wanted to move away from that method for this project and we’re using Turf.js to replicate many GIS functions – but in the browser.

Yep, Turf makes it possible to merge, buffer, contain, calculate distance, transform, dissolve, and perform dozens of other functions all within the browser, “on the fly”, without any software.

After dilly-dallying in Turf for several weeks, our group started making progress this month. We have now pushed to our in-progress website a map with three features made possible by Turf:

  1. Buffer and dissolving buffers to show the Divvy station walk shed, the distance a reasonable person would walk from their home or office to check out a Divvy station. A buffer of 0.25 miles (two Chicago blocks) is created around each of the 300 Divvy stations, hidden from display, and then merged (dissolved in traditional GIS parlance) into a single buffer. The single buffer –called a “super buffer” in our source code – is used for another feature. Currently the projection is messed up and you see ellipsoid shapes instead of circles.
  2. Counting grocery stores in the Divvy station walk shed. We use the “feature collection” function to convert the super buffer into an object that the “within” function can use to compare to a GeoJSON object of grocery stores. This process is similar to the “select by location” function in GIS software. Right now this number is printed only to the console as we look for the best way to display stats like this to the user. A future version of the map could allow the user to change the 0.25 miles distance to an arbitrary distance they prefer.
  3. Find the nearest Divvy station from any place on the map. Using Turf’s “nearest” function and the Context Menu plugin for Leaflet, the user can right-click anywhere on the map and choose “Find nearby Divvy stations”. The “nearest” function compares the place where the user clicked against the GeoJSON object of Divvy stations to select the nearest one. The problem of locating 2+ nearby Divvy stations remains. The original issue asked to find the number of Divvy stations near the point; we’ll likely accomplish this by drawing an invisible, temporary buffer around the point and then using “within” to count the number of stations inside that buffer and then destroy the buffer.
Right-click the map and select "Find nearby Divvy stations" and Turf will locate the nearest Divvy station.

Right-click the map and select “Find nearby Divvy stations” and Turf will locate the nearest Divvy station.

* I send one email to new people who join us at Open Gov Hack Night on Tuesdays at the Mart to send them a link to our GitHub repository, and to invite them to a Dropbox folder to share large files for those who don’t learn to use git for file management.

Study recommends designing bike paths for bikes, not for sharing

running and bicycling on the lakefront trail

Some parts of the Chicago Lakefront Trail have a 2-foot wide side path designed for pedestrians but the study reviewed very cases where bicyclists crashed with pedestrians. It’s unknown if this side path results in fewer crashes than the parts of the Lakefront Trail without it. Photo: Eric Allix Rogers

The Active Transportation Alliance posted a link on Facebook to a new study [PDF] in the Open BMJ from December 2014, a free peer-reviewed “version” of the British Medical Journal, and said it “conclusively shows separated space reduces crashes and the severity of injuries when crashes occur”.

The posting was in the context that bicyclists and pedestrians using the Lakefront Trail should have separate paths. I agree, but there’s a problem in how they stated the study’s support for separation.

I wouldn’t say that the study “conclusively” shows that bicyclists would fare better on paths without pedestrians. The study reviewed fewer than 700 crashes in two Canadian cities. Only 11% of those crashes occurred on multi-use trails and only 5.9% of the crashes were with a pedestrian or animal (the two were grouped) – this sample size is too low from which to draw that kind of conclusion.

The study didn’t report the association (correlation) between crash severity and pedestrians. The authors didn’t even recommend that bicyclists and pedestrians have separate paths, but instead wrote “These results suggest an urgent need to provide bike facilities…that are designed [emphasis added] specifically for bicycling rather than for sharing with pedestrians”.

While I don’t discount the possibility that separating bicyclists and pedestrians in off-street corridors will reduce the number of crashes and injuries when those two user groups collide, it’s imprudent to call this study “conclusive” when linking it to the measure of crashes between bicyclists and pedestrians.

The study’s primary conclusion was that bicyclists crash more often when there are high slopes, fast moving cars, or no bike lanes and the authors recommended that bike infrastructure be built for bicycling. That’s a solid recommendation and I recommended that you sign Active Trans’s petition advocating for separate facilities in the North Lake Shore Drive reconstruction project.

Working with ZIP code data (and alternatives to using sketchy ZIP code data)

1711 North Kimball Avenue, built 1890

This building at 1711 N Kimball no longer receives mail and the local mail carrier would mark it as vacant. After a minimum length of time the address will appear in the United States Postal Service’s vacancy dataset, provided by the federal Department of Housing and Urban Development. Photo: Gabriel X. Michael.

Working with accurate ZIP code data in your geographic publication (website or report) or demographic analysis can be problematic. The most accurate dataset – perhaps the only one that could be called reliably accurate – is one that you purchase from one of the United States Postal Service’s (USPS) authorized resellers. If you want to skip the introduction on what ZIP codes really represent, jump to “ZIP-code related datasets”.

Understanding what ZIP codes are

In other words the post office’s ZIP code data, which they use to deliver mail and not to locate people like your publication or analysis, is not free. It is also, unbeknownst to many, a dataset that lists mail carrier routes. It’s not a boundary or polygon, although many of the authorized resellers transform it into a boundary so buyers can geocode the location of their customers (retail companies might use this for customer tracking and profiling, and petition-creating websites for determining your elected officials).

The Census Bureau has its own issues using ZIP code data. For one, the ZIP code data changes as routes change and as delivery points change. Census boundaries needs to stay somewhat constant to be able to compare geographies over time, and Census tracts stay the same for a period of 10 years (between the decennial surveys).

Understanding that ZIP codes are well known (everybody has one and everybody knows theirs) and that it would be useful to present data on that level, the Bureau created “ZIP Code Tabulation Areas” (ZCTA) for the 2000 Census. They’re a collection of Census tracts that resemble a ZIP code’s area (they also often share the same 5-digit identifiers). The ZCTA and an area representing a ZIP code have a lot of overlap and can share much of the same space. ZCTA data is freely downloadable from the Census Bureau’s TIGER shapefiles website.

There’s a good discussion about what ZIP codes are and aren’t on the GIS StackExchange.

Chicago example of the problem

Here’s a real world example of the kinds of problems that ZIP code data availability and comprehension: Those working on the Chicago Health Atlas have run into this problem where they were using two different datasets: ZCTA from the Census Bureau and ZIP codes as prepared by the City of Chicago and published on their open data portal. Their solution, which is really a stopgap measure and needs further review not just by those involved in the app but by a diverse group of data experts, was to add a disclaimer that they use ZCTAs instead of the USPS’s ZIP code data.

ZIP-code related datasets

Fast forward to why I’m telling you all of this: The U.S. Department of Housing and Urban Development (HUD) has two ZIP-code based datasets that may prove useful to mappers and researchers.

1. ZIP code crosswalk files

This is a collection of eight datasets that link a level of Census geography to ZIP codes (and the reverse). The most useful to me is ZIP to Census tract. This dataset tells you in which ZIP code a Census tract lies (including if it spans multiple ZIP codes). HUD is using data from the USPS to create this.

The dataset is documented well on their website and updated quarterly, going back to 2010. The most recent file comes as a 12 MB Excel spreadsheet.

2. Vacant addresses

The USPS employs thousands of mail carriers to delivery things to the millions of households across the country, and they keep track of when the mail carrier cannot delivery something because no one lives in the apartment or house anymore. The address vacancy data tells you the following characteristics at the Census tract level:

  • total number of addresses the USPS knows about
  • number of addresses on urban routes to which the mail carrier hasn’t been able to delivery for 90 days and longer
  • “no-stat” addresses: undeliverable rural addresses, places under construction, urban addresses unlikely to be active

You must register to download the vacant addresses data and be a governmental entity or non-profit organization*, per the agreement** HUD has with USPS. Learn more and download the vacancy data which they update quarterly.

Tina Fassett Smith is a researcher at DePaul University’s Institute of Housing Studies and reviewed part of this blog post. She stresses to readers to ignore the “no-stat” addresses in the USPS’s vacancy dataset. She said that research by her and her colleagues at the IHS concluded this section of the data is unreliable. Tina also said that the methodology mail carriers use to identify vacant addresses and places under change (construction or demolition) isn’t made public and that mail carriers have an incentive to collect the data instead of being compensated normally. Tina further explained the issues with no-stat.

We have seen instances of a relationship between the number of P.O. boxes (i.e., the presence of a post office) and the number of no-stats in an area. This is one reason we took it off of the IHS Data Portal. We have not found it to be a useful data set for better understanding neighborhoods or housing markets.

The Institute of Housing Studies provides vacancy data on their portal for those who don’t want to bother with the HUD sign-up process to obtain it.

* It appears that HUD doesn’t verify your eligibility.

** This agreement also states that one can only use the vacancy data for the “stated purpose”: “measuring and forecasting neighborhood changes, assessing neighborhood needs, and measuring/assessing the various HUD programs in which Users are involved”.

Morgan CTA station ranks highly in rail system for building permits

Let Your Conscious Be Your Guide

The gutted cold storage warehouse in the background is within a quarter mile of the Morgan CTA station. Photo by Seth Anderson.

Excluding all of the Chicago Transit Authority stations in the central business district you’ll find that the new Morgan station ranks highly in the number of building permits issued within a quarter mile. It has a top spot when you calculate those permits’ estimated project costs. The CTA recently discussed with DNAInfo the results of a preliminary study it conducted that showed how the Morgan station is at the center of a lot of construction growth in the West Loop/Fulton Market area, and a contributing factor to this growth.

Now that Licensed Chicago Contractors shows you the two nearest CTA and Metra rail stations to each building permit, and I’ve become well-versed in writing PostGIS queries on the fly, I wrote a query that lists the CTA stations with the most building permits within a quarter mile (“nearby”).

First, though, let’s count how many stations don’t have permits nearby. With the query at the bottom you get a list of station names, the number of permits nearby, and a sum of the estimated costs of those permits sorted by the number of permits. Since I used a “LEFT JOIN” I also get a count of all the permits (the table on the LEFT) that don’t have a match with CTA stations (the table on the right).

There are 127 rows returned and a previous count of the table told me there are 145 stations, including ones outside the Chicago city limits. (There are stations in Cicero, Wilmette, Evanston, Rosemont, Oak Park, Forest Park, and Skokie.) The first row represents NULL, or all of the stations that don’t have permits nearby. That leaves me with 126 rows and 19 stations without permits, or 19 stations outside the City of Chicago.

I verified this by eyeballing it. I looked at a map and counted roughly 19 stations that wouldn’t have the 1/4 mile overlap with a Chicago building permit. The two Austin stations, on the Blue Line Forest Park branch and the Green Line Oak Park branch, are near Chicago and also showed up as a discrete station in the query results. Austin on the Blue Line was dead last, actually!

Let’s get back on track and look at Morgan now. I don’t think it’s fair to compare the Morgan station area with an expected, higher-activity area like the Loop and Central Business District so I eyeballed the list and started the #1 ranking with the first station outside the CBD.

  1. Armitage (Brown, Purple Express) is the station outside the CBD with the most building permits nearby.
  2. Damen-Milwaukee (Blue)
  3. North/Clybourn (Red)
  4. Addison (Red)
  5. Morgan (Green, Pink)

There you have it, from 2009 to today, the Morgan station had the fifth highest number of building permits outside of the Chicago Central Business District. It beat Fullerton (Red, Brown, Purple) in Lincoln Park, and Roosevelt (elevated and subway combined) in the South Loop. The station’s construction began in 2010 and the grand opening occurred May 24, 2012. During this period Morgan had the second highest amount of aggregated estimated costs at $199,911,953.00, behind North/Clybourn, at $218,118,037.37.

Take this analysis with several grains of Morton salt, though, because the following caveats are important to consider: building permits are really speculative development; much of these may be for kitchen renovations or porch reconstructions; I didn’t look up when it was “for sure” that the station was being built so I don’t know when developers would have become interested.

Looking at a longer period

I will, however, run a few more queries to find how Morgan’s position changes, starting with expanding the query to “all time” data (really the end of 2006 to today). It turns out that when looking through all available years Morgan’s position remains at #5 but other stations change position.

  1. Fullerton
  2. Armitage
  3. Damen-Milwaukee
  4. Addison
  5. Morgan

During this period, which covers the end of 2006 until today, Morgan had the highest aggregated estimated costs of the above five stations, at $236,707,083.00. It beat Fullerton’s amount of $160,825,680.30.

Looking only at “new construction”

Since these include all permit types, including water heater installations and window replacements, it doesn’t give us a good look at economic expansion in the areas surrounding CTA stations. I’ve filtered the data so only “new construction” building permits come through. I’m still interested in stations outside the CBD. Here’s how Morgan performed when looking at purely the quantity of new construction permits issued from 2009 to today:

  1. Armitage, 46 new construction building permits
  2. Southport, 38
  3. Addison (Red), 34
  4. North/Clybourn,
  5. Wellington,
  6. California-Milwaukee,
  7. Belmont (Red)
  8. Ashland (Green, Pink)
  9. Irving Park (Brown)
  10. Fullerton
  11. Damen (Brown)
  12. Division-Milwaukee
  13. Western-Milwaukee
  14. Ashland (Orange)
  15. Damen-Milwaukee
  16. Western-Congress
  17. Paulina
  18. Addison (Brown)
  19. Diversey
  20. Sedgwick
  21. Loyola
  22. Montrose (Brown)
  23. Sox-35th-Dan Ryan
  24. Morgan, 13 new construction building permits

Let’s remove that date filter and look at the whole building permits period of late 2006 to today.

  1. Southport (Brown Line), 80 new construction permits, all-time
  2. Armitage (Brown, Purple), 72
  3. Western-Congress (Blue), 66
  4. Addison (Red), 64
  5. Belmont (Red, Brown), 63
  6. Western-Milwaukee, 59
    Damen-Milwaukee, 59
  7. North/Clybourn, 55
    Diversey, 55
  8. Division-Milwaukee, 53
  9. Sox-35th-Dan Ryan, 51
  10. Wellington, 50
  11. 35-Bronzeville-IIT, 48
  12. Irving Park (Brown), 44
  13. Morgan, 43 new construction permits

Now switching the order method around and Morgan appears better when you look at aggregated estimated costs, from 2009 to today.

  1. Illinois Medical District, $236,020,000.00
  2. North/Clybourn, $172,373,335.00
  3. Loyola, $161,744,075.00
  4. Polk, $106,000,000.00
  5. Grand-Milwaukee, $77m224,500.00
  6. Wellington, $72m802,300.00
  7. Belmont (Red), $71,300,302.00
  8. Morgan, $68,300,800.00

Last query – remove the data filter and look at aggregated costs for the whole building permits period where Morgan maintains a top 10 position.

  1. North/Clybourn, $277029045.00
  2. Illinois Medical District, 236,020,000.00 (same as 2009 to today period)
  3. Polk, $188,794,975.00
  4. Loyola, $185,444,075.00
  5. Belmont (Red), $1635,00,085.00
  6. Fullerton, $129,444,051.00
  7. Wellington, $111,335,051.00
  8. Granville, $99,356,702.00
  9. Morgan, $83,995,800.00

The data I’d really like to have, though, is sales tax receipts for the same years.

This is not a valid PostgreSQL query. The brackets indicate the options I was using to retrieve the above results. The geometries are in or transformed to EPSG 3435 (Illinois StatePlane East Feet) and 1,320 feet is a quarter mile.

SELECT
 COUNT (P .permit_) AS count,
 MIN (C .longname) as name,
 min(lines) as lines, 
 sum(_estimated_cost) as sum
FROM
 permits P left join
 stations_cta C
ON
 ST_DWithin (
  ST_Transform (P .geometry, 3435),
  C .geom,
  1320
 )
[WHERE] [EXTRACT (YEAR FROM issue_date) >= 2009] [_permit_type = 'PERMIT - NEW CONSTRUCTION']
GROUP BY
 C .gid
ORDER BY
 [count,sum] DESC

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