Author Archives: arthurhainline

July 2013 Citibike Breakdown

Citi Bike in New York City makes available some limited system data on a month by month basis. Here, I take a look through the data for July of 2013 and try to extract a better understanding of the users of the largest bike share program in the United States.

First, I wanted to know just where are the docking stations for Citi Bike, and which docking stations saw the most use. The map below illustrates this:


Use Map


Citi Bike only covers a small portion of the area of New York City, Manhattan below central park and very limited portions of Brooklyn. We can see that use in Brooklyn and Alphabet City is significantly less than the other areas of coverage.

Next, I wanted to know when people use Citi Bike the most, and for how long. The graph below shows start time of Citi Bike trips by hour. The color represents the average duration of the trips that began in each hour.


Starttime by hour w trip duration



And now a similar graph with the end time of trips.


Endtime by hour w trip duration



Mostly, we see what we would expect. The spikes occur when people are commuting to and from work. We can even see how many people start their trip for work in the 8:00 hour and arrive in the 9:00 hour, with a similar phenomenon in the afternoon during the 5:00 and 6:00 hours. We also see that those rides in the small hours of the morning tend to be the longest.

Next, I wanted to know some more about the demographic of the riders. Below is a graph showing the breakdown of Citi Bike annual subscibers by birth year.


Number of Records by Birth Year



We can see that Citi Bike is most popular with people ages 25-40, and especially so with people who are 29-35.

Now we explore the Gender break down. Also, I looked into how gender correlates with the average trip duration.


Number of Records by Gender w Average Trip Duration



We can see that males more than triple females in the number of subscribers, and they tend to have slightly shorter trip durations. Keep in mind that this still only applies to annual subscribers. One time customers are not required to give their personal information.

So, how much of the use of Citi Bikes is devoted to the annual subscribers?


Number of Records by Subscriber Type with Average Trip Duration


Subscribers account for nearly quadruple the number rides taken.

In a short time, from limited data, we now have a better understanding of the users of New York City’s bike share program.

Frequency of Soyuz Launches

The International Space Station has been serviced by two manned spacecraft, the American Space Shuttle and the Russian Soyuz. Since the decommissioning of the Space Shuttle Program, the Soyuz remains the only spacecraft to transfer crew members to and from the ISS. I wondered how the retirement of the Space Shuttle effected the launch rate of the Soyuz spacecraft. The bar graph below illustrates the frequency of Soyuz launches beginning with the first manned mission to the ISS.


Frequency of Soyuz Launches


Beginning in 2009–two years before the decommissioning of the Space Shuttles, but only one year before their scheduled decommissioning–the Soyuz spacecraft jumped from making a steady two launches per year to four launches per year. The staggering shown toward the right of the graph represents the Russian Federal Space Agency’s tendency to launch two spacecraft in quick succession, wait a while, then launch two more.

The continuing development of the Dragon V2 spacecraft and others like it, as well as mounting tensions with Russia will likely impact the way astronauts and cosmonauts travel to and from space in the near future.


Last Statements of Texas Death Row Inmates

The state of Texas makes available the last statements of death row inmates dating to 1982. These can be found here.

As forensic science advances, more and more inmates have been exonerated. While living inmates, in some cases, have limited means to pursue their exoneration, I wondered about those who have already paid the ultimate price. I dug through the last statements of over 500 inmates, exploring what these people voiced with their last breaths. The word cloud below illustrates the frequency of the most common words used.




As I read them, what shocked me the most was the number of people who proclaimed their own innocence with their last words. Examining these last statements, I placed them into three broad categories: those that proclaimed innocence, those that confessed guilt, and those that did neither. I realize that this is somewhat subjective, but I think I was rigorous in what I allowed to be placed in the “proclaimed innocence” or “confessed guilt” categories, as perhaps can be evidenced by the large number of statements falling in the “neither” category. Here is the breakdown.


Last Statements in Three Broad Categories


I studied further the last statements that fell into the “proclaimed innocence” category. I evaluated these by race (the three broad races that Texas denotes as well as ‘other’) and by year.


Percent that Proclaimed Innocence by Race


The small differences in the percentage of people who proclaimed innocence here are statistically negligible.

Percent that Proclaimed Innocence by Year


Once again, there is no particular trend that can be discerned looking back year by year.

With this limited sample size, this further examination did not shed further light on those that chose their last words spoken or written to be an expression of their innocence.



Even Year Preference of Quadrennial Events

After devoting several hours of my precious life to watching Olympic Curling on television this year (not to mention the Tim Horton’s Brier), I wondered if quadrennial events, events that occur every four years, like the Winter Olympics, tended to prefer a particular set of four years. I found it odd that three of the most prominent of these events in my mind, the Summer Olympics, the Winter Olympics, and the World Cup all occurred on even sets of years.

To find a somewhat comprehensive list of Quadrennial events, I searched Google for “events that happen every four years,” and took note of every event that I could find within the first ten results. I had also tried searching “quadrennial events;” however, that resulted mostly in obscure events such as “The Quadrennial Alaska Brain Injury Conference” or ” The Mark Twain Quadrennial Conference” while leaving out major events like the World Cup. I wanted the resulting list to be totally contained within the first page of one Google search, so the Mark Twain Quadrennial Conference will have to wait for another project.

Now to define the sets of years. The “centennial” set will include events that occur every four years including the year 2000–so, 2000, 2004, 2008 and so on. The set “centennial + 1″ will include events that take place every four years that include 2001, etc.

From my results, we can see a clear preference for even years:



Number of Quadrennial Events



Moreover, when we look at what the actual events are, a preference for the even sets of years becomes clearer when we take into consideration scale and importance. This is not to downplay the significance of the events that occur on the other years, but surely the Summer Olympic Games and the World Cup attract more attention and coverage than the events that occur in the “Centennial + 1″ and the “Centennial + 3″ category.



Table of Quadrennial Events