Mr. Trash Wheel and an Analysis on Crime in Baltimore
By: Jonathan Haroun
Baltimore can be a tough place to call home. “Baltimore? Oh, that’s where ‘The Wire’ is set!”. “Baltimore? Isn’t that the Heroin Capital of the world?” These responses are all too common to a Baltimorean.
Yet despite these terrible problems, there is no place I would rather have grown up. I spent my formative years throughout the city, most memorably visiting the Science Center and National Aquarium with my family. These visits were the highlights of my childhood, but there were certain aspects of these trips that I enjoyed less than others. I noticed how dirty the walks of the street were. Potato chip bags fluttered in the wind and cigarette butts littered the sidewalks. It was unappealing and uncomfortable. Tourists could commonly be heard commenting about the dirtiness of the city and harbor.
The city recognized that without intervention the trash problem in the Inner Harbor would never get better. Together with a local company, they created ‘Mr. Trash Wheel’, a 50-foot long autonomous machine that scoops downstream trash from the water and captures it internally. In 2014, Mr. Trash Wheel was deployed and could be seen scooping trash in the harbor. Mr. Trash Wheel soon became an image that the city rallied behind as a hope for better days — a cleaner harbor and less crime. Mr. Trash Wheel was a huge success story and still operates in the harbor today. In fact, new iterations have been constructed and placed in other bodies of water in Maryland. Below is a clip of Mr. Trash Wheel in action.
Mr. Trash Wheel has undoubtedly made a major impact on the Inner Harbor water quality, yet what I seek to explore in this article is whether Mr. Trash Wheel also had an impact on the level of crime in the city.
I should preface this discussion by introducing the Broken Window Theory — an economist’s theory that a broken window, or vacant, rundown neighborhood links to disorder and incivility in neighboring streets.
Is it possible that the increased cleanliness of Baltimore’s water led to less violent crimes in the city?
Below is the monthly production of Mr. Trash Wheel:
This graph indicates that Mr. Trash Wheel has consumed a fairly steady amount of trash since his inception. Mr. Trash Wheel has collected all kinds of different trash. The counts of collection of this trash are detailed below.
Let us now explore the number of violent crimes that occurred in Baltimore since the machine’s inception. Violent crimes include Larceny, Assault, Auto Theft, Robbery, Burglary, and Shootings. The city of Baltimore collects and provides this data freely online. Below is a look at how violent crime has changed in Baltimore since Mr. Trash Wheel’s inception.
Now that we have explored the individual trends of crime and trash collected it is time to take a look into their relationship. My initial thought was to look into crime data from one week prior to Mr. Trash Wheel’s trash consumption date. It was commonly mentioned that Mr. Trash Wheel was most busy the days/weeks after major rain and snowstorms that wiped street litter into storm drains which funneled into the Inner Harbor. Therefore, I inferred that in the week before this major consumption the streets would be at their most polluted, which the broken window theory would suggest should lead to maximum crime.
After running a regression on this data I found that they were not only statistically insignificant but also negatively correlated to one another. This result differs from that suggested by the Broken Window Theory.
However, I noticed that this calculation failed to account for the fact that very large quantities of trash already existed in the harbor prior to Mr. Trash Wheel’s first day on the job. In other words, Mr. Trash Wheel wasn’t spending a majority of his time filtering runoff from storm drains but was instead cleaning water and trash that had existed in the harbor for a while. Therefore, the analysis of correlation should take into account the cumulative sum of trash the Mr. Trash Wheel had removed from the harbor.
Under this hypothesis, I calculated a new t-test, which indeed showed a statistically significant correlation between trash removed and the level of crime in Baltimore City (2.23). This result does suggest that Mr. Trash Wheel’s contribution to increasing the cleanliness of the city has led to a reduction in violent crimes.
With this correlation proven, I was interested in expecting what types of trash were most commonly associated with a high crime rate. I separately summed each trash type over this period and ran a linear regression to inspect the statistical significance of each.
I discovered that chip bags and glass bottles collected by Mr. Trash Wheel were most commonly associated with higher crime rates a week prior. This is an intuitive result according to the Broken Window Theory. Among all trash types, chip bags and glass bottles are most visible to pedestrians. They would give the strongest image of a neglected neighborhood or waterway, which would lead to higher crime rates as according to the Broken Window Theory. Similarly, cigarette butts are the least positively correlated with crime. Given that cigarette butts are the smallest trash type listed, it makes sense that they would be least correlated with crime according to the Broken Window Theory. Therefore, city officials worldwide should be most concerned with cleaning large litter to give a general impression of order in the streets.
Baltimore is not the only city with a major crime or littering problem. City governments should turn to Mr. Trash Wheel as inspiration for how to approach these problems together. While not all cities may be suitable for a giant floating trash collector, they should recognize the multidimensional impact of cleanliness. According to the collected data, politicians should be particularly aware of trash clearly visible to pedestrians, as the data suggests this type of trash is particularly linked to violent crime.
Who would have guessed that a giant floating trash robot with googly-eyes could have just a profound impact on the crime rates of Baltimore?
