Category: Data

Links between pedestrian safety and crime

October 25, 2012 / / 4 Comments

Chicago Pedestrian Plan

Safety item 20: Analyze the relationship between pedestrian safety and crime (download the plan)

The 2011 Chicago Pedestrian Crash Analysis identified a strong correlation between community areas with high numbers of pedestrian crashes and community areas with high crime rates. Correlation does not indicate causation and further study is necessary to understand this relationship and the potential broader benefits of pedestrian safety improvements. [From page 62 in the 2012 Chicago Pedestrian Plan.]

ACTIONS

Short Term

  • Identify and obtain funding for this study.
  • Identify a location for safety improvements and obtain data for the “before” conditions.

Mid Term

  • Design and implement pedestrian safety improvements.
  • Develop a pedestrian safety enforcement plan for the area for the duration of the project.
  • Analyze the effects on pedestrian safety and crime.

MILESTONES

  1. Initiate this study by 2013 and complete by 2015.

ADDITIONAL RESOURCES

National Highway Traffic Safety Administration. Data-Driven Approaches to Crime and Traffic Safety (DDACTS). 2011. [I don’t fully see the connection, but this reference was linked to a page on NYC Department of Transportation’s website.]

Pedestrian Crash Analysis

The summary report didn’t contain the word “crime”. The technical report contained 2 mentions, with an additional chart. They are quoted in the ordered list below. Download the summary report.

  1. In an examination of various factors including crime, income, race, language spoken, and Walk Score®, the strongest correlation found was between pedestrian crashes and crime
  2. Finally, crime statistics were compared to pedestrian crashes to determine if a correlation could be identified, using data from the Chicago Police Department (CPD) annual reports for 2005 through 2009. The annual reports include incidences of crime by Chicago Community Area (CCA). The statistics for the years 2005 through 2009 were averaged and compared to the aver- age number of fatal and serious injury pedestrian crashes over the same time period in each CCA. Of these factors, crime was the only variable that correlated to pedestrian crashes. Figure 1 shows the correlation between crime and pedestrian crashes was very high. However, there may be many variables responsible for this correlation.
  3. Figure 1: Crime vs. Fatal and Serious Injury Pedestrian Crashes by Chicago Community Area

Figure 1.

I have a few criticisms of this analysis: it lacks raw data; the data tables included in the technical report are of limited length, listing only the “top” items of any metric; the summary report lists many silly factoids; the maps are low resolution and of a limited scale – their design could be modified to improve their usefulness in communicating the crash frequencies of the marked locations. The analysis is reliable.

The technical report includes the state’s guide on how police officers are trained to fill out a crash report form. It also includes relevant crash reporting laws in Illinois. Download the technical report.

Special post for S.M.

Stolen Bike Registry data: Which train stations have the most bike theft?

September 28, 2012 / / 0 Comments

If you can help it, don’t park your bike on the sidewalk under the tracks at the Clybourn Metra Station. Too many opportunities for theft here. 

The Stolen Bike Registry is a website created by Chicagoans for people to notify the community that their bike has been stolen. I make no claims to the accuracy or completeness (or anything) about this list or the dataset from which it was created. Because of less than optimal data collection practices, and a diversity of website users, the location information is difficult to comb through and present. I’ve used Google Refine to clean up some of the location data so that I can pick out the theft locations that represent CTA or Metra stations.

This is a list of the most reported bike theft locations that are CTA or Metra stations, from about June 13, 2006, to April 2, 2011, representing 1,740 bike theft reports*. It’s not known how many bike thefts were reported to the police because they don’t know.

CTA (13 stations)

Logan Square Blue Line CTA 8
Rockwell Brown Line CTA 5
Addison Brown Line CTA 2
Fullerton Red/Brown Line CTA 2
Paulina Brown Line CTA 2
Western & Milwaukee (Blue Line) CTA 2
Western Brown Line CTA 2
Addison Blue Line CTA 1
Chicago Brown Line CTA 1
Damen Blue Line CTA 1
Ashland Orange Line CTA  1
Cumberland Blue Line CTA 1
Wellington Brown Line CTA 1

The new bike racks at Clybourn Metra station are in a more visible spot. Maybe there’s even a security camera pointed at them some of the time. 

Metra (24 stations)

Clybourn Metra 19
Ravenswood Metra 18
Edgebrook Metra 4
Evanston Main Street Metra 2
Forest Glen Metra 2
Healy Metra 2
Lake Cook Metra 2
Ogilvie Metra 2
57th Street Metra 1
College Avenue Metra Train Station 1
Corner of Maple & Church in downtown Evanston, near Metra 1
Glenview Metra Station 1
Harlem Metra Station Berwyn, IL 1
Irving Park Metra Stop 1
Jefferson Park Metra 1
LaSalle Street Metra 1
Mayfair Metra 1
Metra Station at Davis Street, Evanston 1
Morton Grove Metra Station 1
Prairie Crossing Metra Station 1
Rogers Park Metra 1
Union Station Metra 1
Western Metra Station 1
Wilmette Metra 1

* Reports come from around the world. 10 dates have been excluded because their dates were anomalous, empty, or not possible.

Updated September 30 to correct a Metra station and combine it with another.

My Chicago Card Plus tells me how often I use the CTA

July 9, 2012 / / 0 Comments

In this interview with Chicago Transit Authority president Forrest Claypool, I admitted to him and everyone else in the room (three bloggers and three CTA staff) that I rarely ride the CTA. The purpose of my admission was to explain how I gathered up so many questions. A lot of them come from friends and Grid Chicago readers. I always use my Chicago Card Plus to pay for fares because it’s extremely convenient: I never have to worry about having the correct fare and it can be replaced for a nominal $5 fee, protecting your money (the Chicago Card doesn’t have the same benefit because it can’t be registered). Anyway, it also tracks you and you can look up your history. I looked at it to understand just how rarely I use the CTA.

The Chicago Card Plus website shows your data in two ways: the last 5 transactions, and the last 90 days. It turns out that the last 5 transactions were beyond the 90 day period.

  • June 29, train (Blue Line)
  • May 22, bus (56/Milwaukee)
  • March 31, bus (I don’t remember which, but probably the Belmont bus with my mom)
  • March 31, bus

The fifth transaction was loading the card with more money. I think there was one other bus use on March 31, because the most recent two showed as transfer transactions. So I’ve added one more to the list.

  • March 31, bus

Five uses in 98 days, or 1 ride per 19.6 days.

Finding data about traffic and roads in Illinois

June 16, 2012 / / 0 Comments

There are two good websites that provide information about roads, traffic, and their many attributes. One is provided by the Illinois Department of Transportation (IDOT) called Getting Around Illinois (GAI). The second is the Traffic Count Database System (TCDS).

Both provide Average Daily Traffic (ADT) counts with TCDS making the information easier to find and presents more of it.

The GAI map has an important layer: jurisdiction. With that information you can determine who has “ownership” of a road. Jurisdiction has been an important factor in the nearly year-long delay of the Jackson Boulevard protected bike lane segment from Ogden Avenue to Halsted Street. IDOT has jurisdiction over this segment (which continues east to Lake Shore Drive; the road is also known as Route 66) and is requiring that the Chicago Department of Transportation do more analysis and revise their designs.

If you are looking for ADT counts, I highly recommend TCDS as it uses the more familiar Google Maps and doesn’t require the Microsoft Silverlight plugin (which is slow and often denigrated with poor usability applications).

GAI has truck routes and crash information as well.

Stats from the OECD: Comparing traffic injuries of the United States and Netherlands

May 21, 2012 / / 0 Comments

For an article I’m writing for Architect’s Newspaper about the Chicago Forward CDOT Action Agenda, I wanted to know about traffic injuries and fatalities in the United States, but compared to the Netherlands and Denmark and other places with a Vision Zero campaign (to have 0 traffic deaths each year).

I already knew the OECD had a good statistics database and web application. With a few clicks, I can quickly get a table of traffic injuries (casualties) listing just the countries I want. I can easily select the years I want, too.

In one more click the web application will show a time animated bar chart. A feature I’d like to see added is dividing the figure (in this case traffic injuries) by the population. Check out the video to see what it looks like. The United States looks to be in terrible shape, but our country has several times more residents.

I had trouble downloading and opening the CSV file of the data table I created. The XLS file was damaged, also. The built-in Mac OS X Archive Utility app couldn’t open the .gz file, but I used The Unarchiver app successfully.

My calculations, based on data from OECD (national population and traffic fatalities), Illinois Department of Transportation (IDOT), and the American Community Survey:

Fatalities per 100,000 in 2009

  • United States: 11.02472
  • Denmark: 5.48969
  • Netherlands: 4.35561
  • Sweden: 3.84988
  • Chicago: 16.74891
  • United Kingdom: 3.83555

Chicago’s fatality rate per 100,000 citizens in 2009 was 16.75 (473 deaths on the roads). The fatality rate dropped in 2010: just 11.65 deaths per 100,000 residents (315 deaths on the roads; the population also decreased).

Updated September 28, 2012, to add the United Kingdom.