Sidewalk was hatched out of Google last June as an independent company that will use technology to solve urban problems — yet another example of how the Internet giant has strayed far and wide from its initial mission in online search. The company is based in New York and was conceived by Mr. Doctoroff, along with a team of Google employees led by Larry Page, one of Google’s founders and now Alphabet’s chief executive.

In June, Sidewalk announced that it would help finance a company called Intersection that is installing thousands of Wi-Fi kiosks across New York City, but the company has otherwise said little about its aspirations or what kinds of technologies it might develop.

Thursday’s announcement gave some insights. As part of the Transportation Department competition, Sidewalk will work with the seven finalists to develop a software platform called Flow to help cities diagnose and fix congestion problems.

Flow looks a lot like Google Maps, and the search giant’s mapping data is at the core of the product. But the idea is to help cities dive deeper.

The Flow system makes inferences about where people are coming from or going, so planners could tap on a congested road segment and find out what kind of traffic — morning commuters, for example, or weekend traffic to a baseball game — was contributing to the problem. They would also be able to run virtual experiments such as how much traffic would be reduced if they added a bus route or car pool lane along the choke point.