Before the car took over, urban Americans were resigned to squeezing. American cities had robust transportation systems made up of streetcars, trolleys, omnibuses, and walkable neighborhoods. All these forms of transit are what we would now call high density, packing a whole bunch of people into small spaces. High-density transit cities benefit from emptier roads, which allows people to get where they’re going more reliably and makes them much more pleasant.

New York was once like this. Take a look for yourself at Broadway near Wall Street on a glorious spring Friday, May 13, 1902:

The Library of Congress description for this video describes the traffic as “very heavy,” even though by contemporary measures, street traffic is decidedly light. When the subway opened two years later, it let anyone who had a nickel — roughly $1 in today’s value — travel under the city at 40 miles per hour, all while still adhering to the principles of high-density movement.

Since the day the subway opened, its congestion has been a source of frustration, anger, and discomfort. In the first edition of the New York Tribune after the inaugural journey, the newspaper proclaimed it “the birth of [the] subway crush.” In 722 Miles, a book about the history of the subway, history professor Clifton Hood writes that the subway prior to World War I was likely the most crowded it has ever been. Only a small portion of the system had actually been completed, and engineers underestimated how popular the express trains would be.

But the subway crush transformed New York into what it is today. The subway allowed New Yorkers to easily traverse the city and provided an outlet for some of the world’s densest neighborhoods. “None of the most congested neighborhoods in the world today — in Dhaka, Nairobi, and Mumbai,” historian Tyler Anbinder writes in City of Dreams, “are as densely populated as were the most crowded neighborhoods of the Lower East Side in the decade before World War I.” The subway opened the Upper Manhattan and Bronx farmlands, along with the Queens marshlands, to families who could afford to leave the city’s slums. The city became a daily accordion, its people pushing in and rushing out, humming with economic activity.

The subway also shifted riders’ attitude and prejudices. It brought people from far reaches of the city very close together in a way trolleys never had. Whether this integration helped bust down race and class barriers, as some hoped, people at least put up with each other. This likely had — and continues to have — a profound effect on how New Yorkers view each other. As Richard Florida summarized in a 2015 study on the subject, “Cities are not always more tolerant, but it appears that those that are built to promote interactions between different sorts of people are.”

Americans need to confront their intolerance for cramming together.

But by the mid-20th century, U.S. cities were emptying, with middle-class Americans moving to the suburbs and the automobile becoming the country’s emblem of freedom and status. The car is the ultimate example of low-density transit, in which one person — sometimes more, but usually just one — takes up much more space than they need. Commuters were no longer forced to accept the existence of others, and space became the ultimate good. A 1949 Ford brochure, for example, declared that year’s car model was “a living room on wheels” — and the antithesis of the crush.

Today, big U.S. cities are filling up again. Almost two-thirds of Americans live in cities; New York and Washington, D.C., for example, have 700 more people per square mile than they did in 2000. But many of these urbanites no longer tolerate the hordes that our grandparents or great-grandparents did. I recently met someone who lives in one of the densest, most transit-friendly neighborhoods in New York but bought a car in anticipation of having a kid, as if it was self-evident that anyone with a kid needs a car. Minutes later, she lamented the city’s incorrigible gridlock. She exemplified the tension of so many new urbanites: They want the perks of high-density living without the inconveniences that come with it. It’s an untenable arrangement on which private companies seek to capitalize.