Category: Information

Which is safer: Bike without helmet, or drive without seatbelt?

December 3, 2011 / / 0 Comments

Cycling on Milwaukee Avenue at Grand Avenue and Halsted Street, one of the most crash-likely intersections on Milwaukee Avenue.

Someone asked me on Twitter: “What’s more dangerous, biking with no helmet or driving with no seatbelt?” It’s an odd comparison, but I decided to try to crack the question.

Here’s my answer:

If your definition of “dangerous” is “the likelihood that you’ll receive an injury while traveling in/on the vehicle”, assuming that the likelihood of being in a crash is the same*, then you are more likely to sustain an injury while cycling while wearing a helmet than while driving or being a passenger in a car while wearing a seatbelt.

Here’s the data, for crashes in Chicago in 2007-2010:

Table 1: Yes, recorded to be wearing a helmet while bicycling

Injury Type Frequency (each number is a person) Percent of total
No injury 3 7.32%
Possible injury 6 14.63
Non-incapacitating injury 26 63.41
Incapacitating injury 6 14.36
Fatality* 0 0
Total 41 100%

A value of 0 fatalities in four years for people wearing a helmet absolutely DOES NOT mean that a helmet prevented a fatality. The “contrary” data for “Recorded to not be wearing a helmet or having safety equipment” shows that there was 1 fatality in four years – the data do not suggest that the fatality would be prevented if the person was wearing a helmet. The sample size is so small that this data is meaningless.

Table 2: Yes, recorded to be wearing a seatbelt as driver or passenger

Injury Type Frequency (each number is a person) Percent of total
No injury 423,096 89.42%
Possible injury 21,667 4.58
Non-incapacitating injury 23,956 5.06
Incapacitating injury 4,338 0.92
Fatality 93 0.02
Total 473,150 100%

*I don’t think we can determine the likelihood of being in a crash when riding a bicycle because we don’t know the “device miles traveled” of Chicago cyclists. It’s probably possible to approximate the number of vehicle miles traveled by drivers in Chicago, though; I’m not sure about passengers.

Download the data for this article, which includes these additional tables:

  • Bicycling: All injuries
  • Bicycling: No safety equipment or helmet wearing
  • Bicycling: Unknown usage of safety equipment
  • Auto: All injuries
  • Auto: No safety equipment or helmet wearing
  • Auto: Unknown usage of safety equipment

Last minute vote on bicycle data visualization project

November 28, 2011 / / 0 Comments

The United States Department of Transportation is holding a data visualization competition and Chicago bike crash locations are one of the topics.

From Michael Carney:

I started this project because, basically, I thought it would be interesting to make a map of bike crash locations around Chicago and present it to my GIS class at UIC. Sebastian Lew and I collaborated for several months and it evolved into something more. Using ArcGIS, we were able to symbolize streets by level of overall crash intensity, calculate crashes per mile on streets, perform hot spot analysis to identify areas with high numbers of crashes, compare ridership levels with crash levels, examine temporal trends in crash activity, and perhaps most importantly, assess the effectiveness (at least at a basic level) of current bicycle infrastructure. At the very least I hope our project can help you plan a safe route to work, at the most I hope it can be used by policymakers and planners when considering how and where to expand Chicago’s bike infrastructure.

Vote today only. View the project.

Should Cook County become a state?

November 23, 2011 / / 0 Comments

“A state Republican legislator has introduced a bill to the Illinois General Assembly to separate the Chicago’s county from the state–effectively making the midwestern city the 51st state in the union” via Yahoo! News.

I’m just thinking aloud here:

  • We could fix our own transit funding issues. We wouldn’t have to compete with transit funding for downstate agencies (at the state level, competition at the federal level would still exist).
  • We’d be a very small state, 5.3 million.
  • Metra would be tough to deal with, unless it came under CTA control first! Har har.
  • I think this could make the State of Chicago a larger economic powerhouse without the meddling of so many different legislators.

What else would be different if Chicago (and Cook county) was its own state?

“These liberal policies are an insult to the traditional values of downstate families,” Mitchell told the Decatur Tribune. “When I talk to constituents, one of the biggest things I hear is ‘Chicago should be its own state . . . .Our voters’ voices were drowned out by Chicago.”

That’s kind of funny. Like Chicagoans are a bunch of abortion-having, dolphin-saving, vegan, bisexual couples.

Cycle mapping

November 10, 2011 / / 13 Comments

A screenshot of Critical Map: Milano. 

What are the sites that will let you either draw or upload a bike route to share with others?

And what are the sites or mobile apps that give you cycle routing?

A screenshot of Bike Share Map: London, UK.

And other bike-related maps?

I’m just simply researching and collecting links to cycling-related map mashups and apps.

Revisionist history: Karachi changed maps to support illegal housing development

October 31, 2011 / / 0 Comments

I’m still reading Instant City: Life and death in Karachi, the book I reviewed a little over a week ago.

It seems that Winston Smith from 1984 works for the Karachi city government. Author Steve Inskeep describes his investigation into the life of activist Nisar Baloch and the alleged encroachment, a common occurrence, on a public park, Gutter Baghicha.

Nevertheless the investigator did find houses under construction in several of the acres that were in dispute. Now it became a matter of dry law, or so it seemed. One of the simpler questions was whether the construction was inside the national park or outside of it.

A map of the national park from 2005 clearly included the land where construction had begun. A map from 2009 clearly excluded the land where construction had begun.

Curiously, both maps were produced by the Karachi city government, which seemed to have altered the shape of the national park to accommodate the new settlement. That was how the city managed to claim with a straight face that the settled was outside the park. When I compared the two maps with Google images of the national park under construction, it was clear that Shehri [a local environmental protection and advocacy group suing the city about this encroachment] was right: the park’s boundaries had moved. The 2005 design of he park could not possibly fit in the remaining land now designated for it.

You’ll have to read the book to know the end of the story (buy it on Amazon and Kindle), and the end of Nisar’s life. The map below shows the park in the center of the city.


View Larger Map