The Design Bible That Changed How Americans Bike in Cities

A movement has brought safer bicycle lanes to the United States. But it took a manual to spread them.

A woman rides a bicycle down a bike lane in Denver
A bike lane in Denver (RJ Sangosti / The Denver Post / Getty)

When I first started working in New York, in 2007, bicycling seemed like an activity best left to the pros. One of the city’s stock characters was the fearless bicycle messenger, wearing a heavy chain lock around the waist and whipping through traffic with supreme confidence.

Ten years later, the bicycle always feels like an option. It’s not my primary means of transit, but I’ve racked up 723 miles in four years on the Citi Bike bike-share service—a significant accumulation of short trips to and from the subway, after-work rides to friends’ apartments, and fun rides on sunny days.

The biggest reason my relationship with the bicycle changed is that during the last decade, New York built 98 miles of protected bicycle lanes—lanes that are painted on the street, but protected with concrete curbs, Jersey barriers, or (most commonly) flexible plastic posts that stop drivers from double-parking or otherwise violating the space.

New York was the first American city to embrace this kind of safe-cycling lane, but it’s no outlier. Minneapolis now has about 15 miles of protected bike lanes; Chicago has roughly 25, and San Francisco, 16. In the last five years, Denver; Los Angeles; Austin, Texas; and Memphis, Tennessee, began to build networks of protected bike lanes. More than 100 American cities have at least one protected bike lane, according to the cycling-advocacy group PeopleForBikes. Protected lanes now exist in Salt Lake City, and Honolulu—and Tallahassee, Florida; Grand Rapids, Michigan; Cedar Rapids, Iowa; Springdale, Arkansas; and Huntsville, Alabama.

How did the protected bike lane suddenly become common in America? Advocates will tell you it was the result of stalwart activism. And trailblazing, politically daring transportation officials did play a part in bringing better bike lanes to the nation. But the spread of bike lanes to so many corners of the country couldn’t have happened without a simple, ordinary technology: a set of street-design standards, written down in a book so that less daring engineers didn’t have to blaze their own trails anew.

Street-design standards are a labor-saving and risk-reducing technology that memorialize the expert judgment of the traffic-engineering field. Designing a street includes an enormous number of judgment calls, having to do with questions of space, time, and information.

Geometric standards, like the width of traffic lanes and tightness of curves, come from the American Association of State Highway and Transportation Officials (AASHTO), which publishes the “Green Book” (aka A Policy on Geometric Design of Highways and Streets) and other road-design guides. Standards for signs and signals come from the Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD), which is published by the federal government. The MUTCD has the force of law, which is why traffic lights and road signs look virtually identical across the country. For example, an American stop sign must be a red octagon, no less than 30 inches square (36 inches on a multilane road). AASHTO’s guidebooks set standards on large, federally regulated roads, but only issue advisory guidance for urban streets. Still, they have enormous influence and are often treated as standards.

Street-design standards are essential to minimize confusion among people traveling from place to place. Only the largest cities have much in-house ability to design new street projects. A city of 130,000 people might have no more than a half-dozen engineers and planners who play any significant role in designing streets. Standards also help shield cities from legal liability. Generally, a city cannot be sued by a person who crashes into a tree and blames the road if that road was constructed in accordance with prevailing standards.

But standards can also replicate failure. Sometimes, that’s because codified “expert judgment” turns out to be wrong. But it can also be because standards embed value judgments in ways that are rarely examined. The traffic engineer Chuck Marohn has argued that the dominant street-design standards in America overvalue the speed and flow of automobile traffic, at the expense of pleasant neighborhoods that are walkable, bikeable, and financially productive.

For example, AASHTO books generally recommend up to 12-foot traffic lanes, which feel safe to drive at 40 miles per hour.* But in dense cities, where the speed limit may be 25 miles per hour or less, it would be better to make speeding feel uncomfortable for drivers by striping narrow, 10-foot lanes for cars. Similarly, the Northeastern University professor Peter Furth has pointed out that on roads with medians, the MUTCD doesn’t require pedestrian signals to provide enough time for people to fully cross the street—only enough time to make it to the center median.

In 2007, a local planner could read the entire MUTCD, as well as the Green Book and every other design standard released by AASHTO—including the bicycle-specific Guide for the Development of Bicycle Facilities—and not find any guidance to help design the kind of protected bike lanes that had already existed in Denmark and the Netherlands for 30 years. Instead, they only offered guidance for two types of bike facility: Pleasant off-street paths (usually in waterfronts and parks), and painted on-street bike lanes.

In part, this reflects the influence of the American “vehicular cycling” movement, which taught that the safest way to bike is to act like you’re driving a car: Confidently “take the lane” so that drivers stay behind you, use hand signals, and ride fast. In the 1980s, when Northern European countries were building protected bike-lane networks, U.S. cyclists were being taught to bicycle in the roadway. And U.S. engineers were adopting the attitude that cyclists didn’t need infrastructure, just proper training.

The rationale for the protected bicycle lane seems obvious in retrospect: Most people don’t want to be “vehicular cyclists” sprinting at 20 miles per hour and mixing it up with cars and trucks.

In 2006, the Portland, Oregon, bicycle coordinator Roger Geller theorized that only a tiny number of people were “strong and fearless” bikers who enjoyed riding in traffic, but that the majority of Portlanders could be described as “interested but concerned.” Interested in biking, but concerned about the stress and danger of car traffic.

The concern is understandable. A study by the University of Westminster’s Rachel Aldred found that, although actual injuries during biking are rare, British cyclists (whose infrastructure is not much better than in the United States) experience a scary “near miss” incident nearly every week. Study participants reported close tailgating, deliberate “problematic passing” by drivers, and road-rage incidents that left them feeling humiliated and powerless. As one participant in Aldred’s study wrote, biking in traffic or unprotected lanes requires “ceaseless vigilance.”

By contrast, riding in a protected lane offers an opportunity to relax, to trundle along at your preferred pace, enjoy city sights, and Zen out. It’s actually fun. The research shows that most people want that experience from biking. In 2015, survey research from Portland State University’s Jennifer Dill and Nathan McNeil found that over half of adults in the 50 largest U.S metropolitan areas have attitudes matching Geller’s “interested but concerned” typology.

This means that to get many more people biking—and therefore improve the environment and public health in American cities—protected bike lanes are a necessity.

In the late 2000s, a number of U.S. transportation leaders set out to finally bring them to this country. In 2007, the New York transportation commissioner Janette Sadik-Khan opened the city’s first on-street protected bike lane on Ninth Avenue. Protected lanes on Eighth Avenue followed the next year, despite fierce media opposition. Under the leadership of Gabe Klein, Washington, D.C., opened its first protected bike lane on 15th Street NW in 2010.

Planners in Minneapolis, Portland, San Francisco, and many other cities were also eager to try out protected bike lanes. Collectively, they’d realized that many of what they considered worldwide best practices were essentially missing from the manuals that guide American traffic engineers and transportation planners. So they resolved to write their own.

To codify their emerging practice, they turned to the National Association of City Transportation Officials (NACTO). NACTO had been formed in 1996 as a forum for big-city transportation planners to swap ideas, but it had never published a design guide before. That became one of its top priorities after Sadik-Khan was named president of the organization. For several months beginning in 2010, a group of 40 consultants and city transportation planners reviewed bike-lane designs from around the world and across the United States.

The result was NACTO’s Urban Bikeway Design Guide, the first national design standard for protected bike lanes. Like other standards, it answers the questions of space, time, and information that are at the heart of street design. How wide should a protected bike lane be? At least five feet, but ideally seven. How does one mix bike lanes and bus stops? Send the lane behind the bus stop, with enough space for bus riders to comfortably board and get off the bus. What about when bike lanes and turn lanes meet? Give bikes their own exclusive signals, or create “mixing zones,” shared spaces where people in cars and on bikes take turns entering the space.

Not everyone is satisfied with the NACTO guide’s answers to these questions. When transportation blogs mention the guide, often commenters will point out that the CROW manual, which governs street design in the Netherlands, is even more accommodating to cyclists, recommending wider bike lanes and more separation between bicycle and car traffic, especially at intersections.

But the NACTO guide also provides domestic legal and political cover. No longer were protected bicycle lanes radical experiments, the kind that might expose a government to a lawsuit. They became further normalized in 2013, when the Federal Highway Administration released a memo endorsing use of the NACTO guide. The departments of transportation in Massachusetts, Georgia, and six other states have also endorsed the guide.

While the NACTO guide may have represented an end run around older standards, it has also succeeded in pulling those standards up. In 2014, the National Committee on Uniform Traffic Control Devices (which recommends changes to the MUTCD) adopted several standards from the NACTO guide, such as bicycle-specific traffic signals. The next edition of AASHTO’s guide to developing bike facilities is likely to include protected bike lanes.

As the research predicted, better bike lanes have led to far more people biking. Over three-quarters of a million people ride a bike multiple times a month in New York, a 49 percent increase over 2009. Between 2005 and 2015, the share of commuters who bike to work more than doubled in Minneapolis, San Francisco, and Washington, D.C., according to an analysis of U.S. Census data.

The publication of the NACTO bikeway guide didn’t directly result in the creation of any new bike lanes. But the planners and engineers who wrote it recognized that for each of them to further progress in their own city, they had to collaborate on standards that would enable progress in any city.

As it turns out, the Urban Bikeway Design Guide was just the beginning. NACTO later released the more comprehensive Urban Street Design Guide, a broader effort to push back against America’s car-first road designs and define streets that support urban life, with narrow lanes that encourage reasonable driving speeds and traffic signals that give people plenty of time to cross the street. More recently, the organization has published guides on designing streets to speed up public transit, and incorporate storm-water infrastructure.

It’s increasingly a basic tenet of urban planning that American cities must undo the car-oriented street designs of yesteryear. It turns out that realizing that goal isn’t just a matter of political agitation, new transit systems, or better construction funding. Protected bike lanes are growing thanks to one of the simplest technologies imaginable: a book of standards. Manifestos might have helped catalyze the movement. But manuals were necessary to realize its goals.

* This article previously misstated AASHTO's recommendations for traffic-lane size. We regret the error.