Category: Information

Crashes by bike or by foot at different intersections

January 16, 2012 / / 0 Comments

While working on a private web application that I call Chicago Crash Browser, I added some code to show the share of pedestrian and pedalcyclist crashes. The site offers users (sorry I don’t have a web server that can make it public) a list of the “Top 10” intersections in terms of bike crash frequency (that’s bike+auto crash). You can click on the intersection and a list will populate showing all the pedestrian and pedalcyclist crashes there, sorted by date. At the bottom of the list is a simple sentence that tells what percentage pedestrian and pedalcyclists made up at that intersection.

I’m still developing ideas on how this information may be useful, and what it’s saying about the intersection or the people using it.

Let me tell you about a few:

Milwaukee Avenue and Ogden Avenue

I mentioned in my article Initial intersection crash analysis for Milwaukee Avenue that this intersection is the most bike crash-frequent.

23 crashes within 150 feet of the center, 2005-2010

82.61% bike crashes **

17.39% ped crashes.

Ashland Avenue and Division Street

28 crashes within 150 feet of the center, 2005-2010

46.43% bike crashes

53.57% ped crashes **

Milwaukee, North and Damen Avenues

46 crashes within 150 feet of the center, 2005-2010

39.13% bike crashes

60.87% ped crashes **

Halsted Street, Lincoln and Fullerton Avenues

38 crashes within 150 feet of the center, 2005-2010

42.11% bike crashes

57.89% ped crashes **

Montrose Avenue and Marine Drive (Lake Shore Drive ramps)

11 crashes within 150 feet of the center, 2005-2010

90.91% bike crashes **

9.09% ped crashes

Why do you think some intersections have more of one kind of crash than the other?

People walking at Milwaukee-North-Damen.

The Chicago Crash Browser can be made public if I have a host that offers the PostgreSQL database. Do you have one to offer?

Carnage culture dispatch #1

January 12, 2012 / / 0 Comments

I’ve been a “fan” of carnage culture news and discussion for several years, mainly since I started reading Streetsblog (probably in 2007) and their Weekly Carnage series. I write about “carnage culture” here and a little bit on Grid Chicago. But on Grid Chicago I tend to keep the coverage about crash data plus more “reasonable” (a euphemism for less angry, maybe) and objective.

Carnage culture to me is a description of the level of life and property damage Americans are willing to accept as a cost of doing business, and a cost of living. And I think that level of acceptability is much too high. Is the person responsible for these crashes paying for the damage they caused? Did the City bill the driver for the trees, curbs, landscaping, and guardrail he ran into?

I present here the first Chicago Crash Diary. From the photos and background information I received from a reader, combined with the Illinois Department of Transportation crash data, I was able to “reconstruct” a particular damaging crash in 2010. I made a color flyer from this information to quickly distill the details.

It seems continuing our system of having extremely high health care costs (without an equivalent return in quality or faster care when compared to countries with lower health care costs) is an acceptable cost of perpetuating backward ideas about society’s responsibility to take care of its members and refusing to allow a system that shares health care costs for those not already covered by Medicare, Medicaid, or child health insurance programs.

This is like carnage culture: we accept the damage to property, to human lives, and to society, to continue a culture (including our built environment) that depends on and glorifies automobile ownership and driving to places where other modes suffice. Our culture that allows unlicensed drivers, uninsured drivers, drivers with limited education (driver’s education is not needed for those 18 and older), being distracted by cellphones, and lax enforcement,* is the same one that allows $300 billion to be spent on “picking up the pieces” after crashes (study from AAA by Cambridge Systematics). But ours is the same culture that builds its cities and neighborhoods and places of employment to only be accessible by those who can drive.

The cost of crashes are based on the Federal Highway Administration’s comprehensive costs for traffic fatalities and injuries that assign a dollar value to a variety of components, including medical and emergency services, lost earnings and household production, property damage, and lost quality of life, among other things. [This story is interesting because the press release’s angle was that crash costs are three times higher than congestion costs, which is constantly in the news; congestion is apparently something we care more about.]

I don’t think $35 per month liability insurance, or the police, district attorneys, and courts, are protecting us from this damage.

*I could go on. Just search for “top causes of car crashes”.

Logan Square McDonald’s crash map

December 21, 2011 / / 0 Comments

This is part of a series of articles on the issue of lifting the pedestrian street designation on a part of Milwaukee Avenue in Logan Square so that the McDonald’s franchise owner can demolish the building, build a new building, and build a double order point (“tandem”) drive through. Read the first post. 

At the hearing on December 13, 2011, Alderman Reilly asked if there was evidence of injuries or crashes due to the drive through. No one brought this data to the hearing. I cannot directly attribute the crashes to the existence of the drive through (unless I had the original crash reports), the drive through probably generates traffic that would not be there without the drive through, and it causes people to have to turn across a lane of traffic, either to enter the driveway on Milwaukee, or when exiting the driveway onto Sawyer, or when turning onto Milwaukee from Sawyer. I am looking for studies that research the impacts of drive throughs at fast food restaurants and pharmacies.

37 people were involved in 13 crashes within 100 feet of the center of the McDonald’s driveway from 2007-2010. Seven people were injured, one was a pedestrian. Double the search radius to 200 feet and we see 87 people involved in 35 crashes. Now, four pedestrians and cyclist were injured in addition to the 10 drivers and passengers injured.

Download the data in this map. View a larger map. 

This was my testimony at the zoning committee hearing (this may not be verbatim, but it’s really close):

Hello, my name is Steven Vance. I work as a consultant and writer on sustainable transportation advocacy and planning projects. The text amendment to modify the pedestrian street designation may negatively impact the continuity and safety in traffic of all modes along Milwaukee Avenue, which happens to be the city’s most popular bike route.

I ask that McDonald’s provide a traffic impact study before this matter is discussed further.

Lynn, a Logan Square neighbor, describes more of what happened at the hearing, as well as the next step at the Zoning Board of Appeals.

Here’s a map of all pedestrian streets in Chicago. View larger map.

Download a KML file of all the pedestrian streets. Download the shapefile of all the pedestrian streets. Thank you to Azad Amir-Ghassemi and Bill Vassilakis for their help in digitizing the table of pedestrian streets in the zoning code.

Update January 10, 2013

Driving danger

Crash data from the Illinois Department of Transportation show several crashes along Milwaukee Avenue from 2005 to 2011. If this location hadn’t been removed from the P-Street ordinance, McDonald’s would have been required to install both the drive-thru’s entrance and exit on Sawyer, where there is markedly less traffic than on Milwaukee (or not build them at all). This project has not only allowed a documented hazard to persist (despite the P-Street designation), but perhaps to be worsened.

From 2005-2011, there were 3 bike-automobile crashes and 5 pedestrian-automobile crashes within 200 feet of the drive-thru entrance, which includes the intersection of Sawyer and Milwaukee (where many people will drive back onto Milwaukee from the drive-thru exit). There were 82 car-car crashes in the same period. At a nearby intersection, Milwaukee/Dawson, an intersection with a similar retail makeup and traffic count, shows about half the number of crashes.

Some crash analysis based on gender/sex in Chicago

December 13, 2011 / / 0 Comments

A friend sent me an article saying that in London, women were experiencing crashes more often than men while cycling (BBC article). He asked if this was true about Chicago. So I crunched the numbers. This is very low-level, initial, take it with a grain of salt analysis. It appears that that is not the case for Chicago.

It appears that men walking or cycling are involved in disproportionately more crashes with automobiles than women, but not very disproportional.

1. Men make up 72.73% of people cycling (to work, the only trip purpose for which I have data). And they experienced 75.75% of the crashes with automobiles (to where is unknown).

2. Men make up 48.45% of people walking (to work, again, the only trip purpose for which I have data). And they experienced 53.38% of the crashes with automobiles (again, to where is unknown).

This analysis also points out shortcomings in our data. Even with National Household Travel Survey I don’t think I could get very detailed (as the statistics would be too aggregated and the sample size for Chicago would be small). This data is based on two sources: motorist crash reports from 2007-2010 from the Illinois Department of Transportation (IDOT); and American Community Survey “means of transportation to work”. The last time a household travel survey was done in Chicago was 2008 and I just acquired that data last week. I need to figure out how to connect the people and trip tables and then I can do more analysis, getting exposure data for all trips, not just work.

Who bikes?

December 12, 2011 / / 0 Comments

Who bikes? pie chart

From April 2011, via Sightlines Daily, using data from John Pucher and Ralph Buehler, who got it from the 2009 National Household Travel Survey.

Contrary to popular convention, the biggest share of bicyclists isn’t yuppies, it’s low income people. In fact, the lowest-earning quarter of Americans make nearly one-third of all bike trips. Among that group, I would expect to find at least some fraction of working poor, students, the unemployed, and retired people of modest means. No doubt there are almost as many reasons to bike as there are cyclists, but it’s clear that bikes are a favored choice among those on a budget.

The big takeaway for me, however, is looking beyond low-income riders. Bicycling is remarkably evenly distributed among the remaining three quartiles. With the exception of the over- represented bottom quartile, bike trips don’t appear to be the province of any one income class more than any other.