It’s early morning in downtown Seattle when two cars roll to a stop at the intersection of Pine and First. The city is static at this hour, even the historic, bustling market just down the hill. Then, an urban upheaval so rapid it would make a developer shake. As the vehicles idle at a signal, the lane beside them acquires parking brackets. The traffic lights before them shoot into the sky, replaced by stop signs. The final change affects the very ground beneath the cars: They’re now blocking a bike lane until, a moment later, they’re swept away too.
Metamorphoses like these are easy to conjure in A/B Street, a game that allows users to reconfigure the layout of Seattle streets on a map and glean the impact of these changes to the city’s congestion. Ex-Googler and Montlake resident Dustin Carlino released the alpha version of the traffic simulator this spring. Though he’d worked on it for two years and used pre-pandemic movement data to inform its projections, the game’s first iteration arrived at an auspicious moment for radical proposals in urban planning. Lighter traffic after the Covid-19 outbreak had spurred the city to reimagine many of its roads, leading to blocked-off Stay Healthy Streets and rerouted buses.
Users can make similar changes in A/B Street. The game challenges players to plot the swiftest forms of their commutes—via car, bus, bike, or foot—and optimize the cadence of traffic signals. It also allows them to tinker sans competition: close an intersection for construction here, reverse a street direction there.
The concept for the simulator emerged from Carlino’s own experience with Seattle’s street design. As a cyclist, he took an interest in the conflicts over bike lanes after moving here from Austin.
Contentious city projects, such as the redesign of 35th Avenue Northeast, intrigued him. The decision-making process “didn’t seem very rigorous, or if it was, it wasn’t really clearly explained to the public.” That’s when he realized he wanted to make a traffic simulator that not only tracked cars but also included other forms of transportation.
He also wanted it to be free and accessible, with an open source license to invite modifications—a precursor, potentially, to policy solutions. The idea of a game designed for social change attracted user experience (UX) designer Yuwen Li to the project. She says it “serves as a channel for people to actually talk about [their] ideas and validate those ideas.”
But could A/B Street actually influence Seattle Department of Transportation’s decisions about certain roads? SDOT’s communications team praises the simulator, saying it demonstrates “great ingenuity,” but also notes that real-life complexities can’t be captured in a simulation.
Carlino doesn’t disagree. While his game draws from modeling by the Puget Sound Regional Council and Open Street Map, it represents a simplified approach that he acknowledges could be more accurate. Still, it does allow users to quickly test proposals and gauge their prospects, paving the way, perhaps, for a quicker office trip or Trader Joe’s run in the future.
“The most important goal, the thing that I feel like isn’t covered by anything else out there today,” he says, “is it’s a way for members of the general public to say, ‘I experience some problem in my commute every day, and I just want to try to fix it.’”