When Laura Schewel worked for an energy think tank and then the Federal Energy Regulatory Commission, she wanted to develop policies that would stimulate sales of electric cars. The trouble was, there wasn’t comprehensive and reliable data about where and when people drive.

Typically, transportation experts construct predictive models to describe traffic patterns, or they conduct expensive surveys. Neither is particularly easy to do. “We have no idea what’s happening on the roads. Just none,” Schewel says. “When you compare that to what we know about what people watch on TV, it’s absurd.” 

While in a PhD program at the University of California, Berkeley, she realized that people actually were revealing where they drive—to their cell-phone companies and GPS navigation services. She thought: what if I could get access to that data? It took a year to persuade companies to sell this valuable and sensitive information to a small startup she formed, StreetLight Data. The company, which aggregates and analyzes the signals from cell phones and dashboard GPS navigation systems, makes it easy for just about anyone to do what Schewel had long envisioned—see detailed maps of where, when, and how people travel through cities.

With software that she and her team developed, Schewel can type in an address and find the demographics of the people who drive by or stop near that location. The system shows when they drive by, how frequently, and even what neighborhoods they’re coming from. (Importantly, Schewel’s algorithms analyze the movements of groups of these devices, rather than individual units. That means StreetLight’s analytics can’t be reverse-engineered to reveal any given individual’s movements.) 

The information is appealing to customers far beyond the transportation–policy world. A medical office, an auto repair shop, and a small restaurant chain have been using StreetLight’s software to help them decide where to open new locations and place billboards. And the nonprofit Oakland Business Development Corporation is using the software to demonstrate that people with disposable income often spend time in Oakland even if they don’t live nearby. The data, the group hopes, will encourage small businesses and national chains to consider opening up shop in the city’s struggling downtown, which has 400 vacant storefronts and office buildings in one square mile.

Schewel still believes she can make transportation more efficient. But rather than trying to persuade people to be green, she is focused on helping businesses—which have become “the most powerful behavioral-change force in America”—make it easy for people to do greener things. For example, if suburbanites can do some shopping near their offices in downtown Oakland on their commutes home, that might reduce the mileage they would otherwise have to drive. Naturally, Schewel backs up that idea with data: 30 percent of all miles driven in the U.S. are related to shopping.

—Jessica Leber