An image from the grand opening of Manhattan's Second Avenue Subway line in 2017. Officials have been criticized for opening it before it extended past East 96th Street, a dividing line that separates one of Manhattan's wealthiest neighborhoods, the Upper East Side, from East Harlem, one of the poorest.
An image from the grand opening of Manhattan's Second Avenue Subway line in 2017. Officials have been criticized for opening it before it extended past East 96th Street, a dividing line that separates one of Manhattan's wealthiest neighborhoods, the Upper East Side, from East Harlem, one of the poorest. Rainmaker Photo/MediaPunch/IPX

A new study analyzes Twitter data and finds that racial segregation not only divides us based on where we live, but how we travel around cities.

American society has long been split across the fault lines of class and race. William Julius Wilson famously observed that poor African Americans who comprise the “truly disadvantaged” remain substantially isolated from the rest of society and the American economy. But not only are Americans divided by race, we are divided by how we travel about the city for everyday activities like shopping, visiting friends and family, working, or going out to eat. Race is the defining element of this segregation of mobility: Black households of all income groups and classes are more isolated and limited in where and how they move around cities, and rarely enter middle-class white areas.

A recent study by some of the world’s leading poverty researchers, including Robert Sampson and Mario Small of Harvard University, sheds new light by tracking the way different classes and races of people are segregated in our cities—not only based on where they live and grow up, but in where they travel in the city.

The researchers used Twitter data to map the everyday mobility patterns of residents in America’s 50 most populous cities and their surrounding metro areas. The study analyzed some 650 million geo-tagged tweets by 400,000 people for the 18-month period stretching from October 2013 through March 2015. They linked those tweets to neighborhoods where people lived and the places they traveled both throughout the cities and in the larger metropolitan area in their day-to-day lives. The researchers separated neighborhoods into poor and non-poor (based on the percent of households under the federal poverty line) and by whether they are mainly white, black, or Hispanic.

The map below provides an example of how the Twitter data shows an individual’s movements about the New York City metropolitan area. This person who lives in Manhattan mainly visits Manhattan and New Jersey, based on their tweets, with much more limited travel to Brooklyn, the Bronx, Queens, or Staten Island.

Source: Proceedings of the National Academy of Sciences

The study finds minority households are segregated in the ways they move about in their everyday lives. Just as minority households are isolated in where they live, they are also isolated in the neighborhoods they travel to and visit. This is the case even though residents of poor minority neighborhoods travel just as widely across cities as other groups. Ultimately, race plays a bigger role than income or class in the ways we are segregated in living and moving about our cities.

For one, people of all classes, races and ethnicities travel similarly throughout the city. On average, people visited roughly 15 neighborhoods within their city’s boundaries and 18 neighborhoods across its broader commuting zone. Residents of poor neighborhoods visited only slightly fewer neighborhoods compared to those from more affluent areas. Regardless of their economic status, residents of black neighborhoods traveled to the greatest number of neighborhoods.

The average distance people traveled was also similar across class, race and ethnicity. On average, people traveled roughly 3.3 miles per trip, though this varied by city. Residents of Los Angeles traveled an average 4.5 miles, while New York residents traveled slightly less than 3 miles per trip. Those who lived in predominantly black neighborhoods, both poorer and more affluent, traveled slightly farther on average compared to those from predominantly white neighborhoods.

But, even though residents of all types of neighborhoods—across class, race and ethnic lines—traveled similar distances and visited a similar number of neighborhoods, what differed substantially were the kinds of neighborhoods that they visited. To get at this, the study examined the exposure of people to different kinds of neighborhoods. Here, it found that regardless of their socio-economic class, the residents of predominantly black and Hispanic neighborhoods are far less likely to travel to middle-class or white neighborhoods.

Indeed, the residents of poor white neighborhoods were much more exposed to middle-class white neighborhoods, compared to the residents of nonpoor black or Hispanic neighborhoods. As Sampson told me in an email: “What is interesting is that travel is not subject to the same mechanisms used to explain residential segregation, such as steering, redlining, discrimination in housing, affordability, and the like. In theory people can and do travel well beyond their home.”

This, the study concludes, indicates that “racial segregation is operating at a higher-order level than typically recognized: Racial segregation is manifest not only where people live but also where they travel throughout a city and whom they are exposed to.”

Source: Proceedings of the National Academy of Sciences

Segregation and social isolation persist even though the residents of poor black neighborhoods travel widely across the city, about as widely as the residents from more affluent white neighborhoods. In reality, the places they travel to, like the places they live in, tend to be among the poorest and least advantaged parts of the city. Even though they move beyond their own neighborhood, they don’t enter middle-class white neighborhoods, and likely the reverse is true.

As the authors of the study put it: “Race thus trumps class in mobility patterns compositionally despite the fact that there are minimal to no differences in distances traveled and the numbers of neighborhoods visited by race.”

Ultimately, America remains a society that is divided and segregated by race both in terms of where we live and the broader interactions that structure our everyday lives.

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