Four principles for the future of city streets
By: Willa Ng
Tags: Cities, Technology, Transportation, Urban Planning

This crowded street in 1910 Los Angeles shows pedestrians, cars, bicyclists, and streetcars intermingled. (Image: Wikimedia Commons)

Four principles for the future of city streets

Cities can leverage design and technology to re-think our streets for pedestrians, bikes, and transit.

This piece was co-written with Graduate Associate Landry Doyle-Wiese.

In the 1920s, American cities debated a question that would shape urban life for decades: “Who is the street for?”

Streets had, for ages, existed not just as thoroughfares but as vibrant hubs of commercial and social activity. And so, at first, the answer was almost everyone: adults, children, horses, buggies, streetcars, vendors, and more.

But the automobile changed that concept. At first, the new technology was seen as a dangerous invader of places where children played, streetcars crossed, and pedestrians strolled — with good reason. In 1925, cars killed over 15,000 people a year. But by the end of the decade, thanks in part to the careful machinations of the car lobby (which went so far as to coin and promote the word “jaywalker” to liken wayward pedestrians as uncouth bumpkins, or “jays”), streets became conduits that get people where they need to go — in fast vehicles.

As Peter Norton explains in his book, Fighting Traffic: The Dawn of the Motor Age in American Cities, cities were “physically destroyed and rebuilt to accommodate automobiles.” Curbs, crosswalks, and traffic lights were installed for the first time to ensure that pedestrians remained in their small portion of the street’s real estate — and crossed only when it was most efficient for vehicles.

These kinds of measures have only escalated over time. To handle peak, rush-hour demand, engineers today will often add more vehicle lanes to cities. And to ensure the safety of pedestrians and cyclists on these high-speed streets, they design even wider vehicle lanes (to account for drivers who drift or veer) and include buffer spaces like shoulders, medians, and parked cars. These acres of pavement — empty for most of each day and night — are neither pleasant to walk around nor conducive to the types of welcoming urban spaces that encourage street life.

Worse, despite all these efforts, our streets are neither efficient nor safe. In 2018, due to congestion, nearly every major U.S. city recorded a downtown last-mile travel speed below 20 miles per hour. In 2017, more than 6,700 pedestrians and cyclists died on U.S. streets due to automobile crashes.

In response to this stark reality, the complete streets movement has pushed forward important design solutions for cities to improve safety and sidewalk activity — while still making sure people can get where they need to go. Cities like Boston and Toronto, for example, have published Complete Streets Guidelines to promote design standards that allow pedestrians, bicycles, and public space to co-exist with cars safely. In 2017, NACTO released its Blueprint for Autonomous Urbanism to “proactively guide the [self-driving car] technology to prioritize people-first design.”

A “complete street” renovation in New York City in 2011. (Image: Flickr User NYCDOT)

At Sidewalk Labs, we think that there is an opportunity to push this critical thinking even further. We are on the cusp of a new era where new technological capabilities are about to converge. These include autonomous vehicles, which can be programmed to follow speed limits or take certain routes; new mobility services like ride-hail and bike-share services, which reduce the need for parking space; and flexible infrastructure, which makes it possible to use street spaces in a variety of ways. These advances have put cities in a position to completely re-imagine streets — and who they are for.

With these trends and capabilities in mind, we’ve developed four principles that have guided the ways we approach street design — and that we think could guide the design of streets in the future. (You can learn more about them, and download the full report on the principles, here):

Principle 1: Tailor streets for different modes.

streets for different modes. Principle 2: Separate streets by speed.

streets by speed. Principle 3: Incorporate flexibility into street space.

flexibility into street space. Principle 4: Recapture street space for the public realm, transit, bikes, and pedestrians.

Principles 1 and 2 go hand in hand: different street types could prioritize different modes — and adjust their width and speed limit accordingly. So do Principles 3 and 4: we can use new technologies to make lanes more flexible — and give space back to people whenever possible.

To illustrate these admittedly abstract concepts, let’s examine how they’d play out in practice on different street types.

Let’s start with streets that prioritize pedestrians. We’ve called these streets Laneways — they’re very narrow and limited to 4mph. Pedestrians would feel comfortable to stroll or linger here.