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…

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.