To ride a bus, you first must know where the bus is going and where it stops. But in Beirut, and in as many as 60 percent of the world’s urban places, there’s no transportation map. The Lebanese capital’s bus system, run by a constellation of private operators and drivers who change by the day, has no assigned stops.

Aarian Marshall covers autonomous vehicles, transportation policy, and urban planning for WIRED.

So in 2017, students at the American University of Beirut formed a startup, funded by grants and sponsorships, called Yalla Bus. Its goal is to prod more students like them onto the city’s opaque and sometimes diresputable bus system. (Yalla means “Let’s go” in Arabic.) At first, the group wanted to create an app that might transmit real-time bus schedules straight to users’ phones. But they realized they needed something simpler first—a map.

“We wanted to do something to help reduce traffic, help the environment, help people get around in something cheaper than taxis or than having a car, because some people can't afford one,” says Yara Nassar, now a former AUB student with Yalla Bus.

To pull off their map, the group did the logical thing: They started by taking the bus and routing paths by hand. Then they talked to drivers about their routes. They visited the owners of the bus fleets that operate in the city, and convinced them to allow the startup to mount GPS trackers on their vehicles. Last month, after two years of work, Yalla Bus rolled out its bus map online. It also went analog, printing and distributing around 3,000 paper copies at the city’s universities.

This month, Yalla Bus published its map of Beirut's informal bus system. Yalla Bus

The AUB students are not the only ones mapping informal bus systems. A civic tech group at the Massachusetts Institute of Technology says more than half of the world’s big cities lack transportation maps. In the past five years, volunteer mapping enthusiasts in cities including Cairo; [Managua], Nicaragua (https://www.mapanica.net/); Amman, Jordan; Nairobi, Kenya; and Addis Ababa, Ethiopia have taken to routes all over their cities to put what already exists onto paper, or into computer data, to be crunched or analyzed. (Lebanon even has another, earlier volunteer mapping group, BusMap.me.) Many of these groups hope to one day use the information they glean to get the attention of local or national authorities—and to use their data to improve the overall transportation systems.

Creating a map doesn’t impose order on the system. Quite the opposite, the volunteer cartographers say. Sarah Williams, a professor of technology and urban planning at MIT, started working in 2012 with local groups and universities in Nairobi to map the city’s popular but privatized minibus “matatu” system. She now works to create digital tools to help other grassroots organizations pull off similar projects across the world. “These bus systems are sometimes considered so informal and rogue, but the maps show that there is an order,” she says. “There is, in fact, a system, and the system could be used to help plan new transportation initiatives.”