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Bicycle Districts x Redlined Districts

Coding the Correlation

Mobility for All Abilities Hackathon 2019

Organized by @Brownbikegirl

Photos of Brooklyn by Dinanda Nooney and P.L. Spurr via NYPL. 1938 Brooklyn Community Zoning Map via National Archive

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The Team

Project Team

Data Team

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Summary

Overview

  • The legacy of 1930s redlining still impacts New York City. We wanted to see how the legacy affected the implementation and type of bicycle infrastructure.

Our findings:

  • Bike lanes were installed earlier in neighborhoods with a Green grade
  • Bike lanes are more likely to be protected in Blue and Green grade areas than in red or yellow
  • More bike lanes per road in red lined districts

Challenges & limitations

  • Data quality (DOT Bike Map: Date & Class III)
  • Gentrification changes meaningfulness over time
  • Issue is layered and other ways should be investigated to understand full scope
  • Statistical challenge with significantly smaller green and blue districts

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Context

Methodology

  • Selected, grouped, and calculated length of existing bike lanes and roads by HOLC districts (QGIS, python scripting)

Data

  • HOLC Historic Lending Maps: Green, Blue, Yellow, Red districts shapefile
  • Bike lanes shapefile
  • ACS 2017 census tract demographic and income data

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Redlining

Early 1930’s, under federal instruction financial institutions refused or limited loans, mortgages, and insurances within specific geographic areas, especially inner-city neighborhoods on the basis of race.

“Residential security maps” were created and classifications on these maps decided the level of investment, or lack thereof. The Fair Housing Act (1968) ended this practice but not its effects.

Hazardous

110

Declining

180

Still desirable

64

Best

14

Classifications (#’s in NYC)

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History of Redlining in NYC

If you were African American, simply getting a mortgage in your NYC neighborhood was pretty much out of the question. As a result, many owners in these areas stopped investing in their properties and neighborhoods fell into decline. This affected huge swaths of New York: in Brooklyn, most of North Brooklyn, as well as Cobble Hill, Gowanus, Sunset Park, Dumbo, Fort Greene, Bed Stuy, East New York and Coney Island were redlined.”

-Brick underground

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Bikes Lanes + Redlined Districts

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Average Bike Lane Installation Year

On average, biking infrastructure was installed three years earlier in blue and green districts than red and yellow ones.*

Red

Yellow

Blue

Green

2010

2012

2009

2007

*only taking into account bike lanes that were installed post 2000.

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Relative Distance

Red

Yellow

Blue

Green

Total Street Miles

2216

3497

1043

150

Total Bike Miles

234

172

81

10

Bike Lanes as % of Street Miles

10.5%

4.9%

7.8%

6.7%

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Classification of Bicycle Infrastructure

Source: NYC Bike Map, DoT

Classified in open data NYC

I

II

III

Classified in NYC Bike Map

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Bike lane type per HOLC district

Type

Red

Yellow

Blue

Green

I (protected)

15.9%

19.4%

21.1%

28.2%

II (standard)

59.5%

54.0%

55.5%

59.2%

III (sharrow)

26.2%

27.8%

26.3%

17.8%

Bike lanes in blue and green areas are more likely to be protected than in historically red-lined areas.

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Thank you

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Appendix

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