CEO Larry Page on Wednesday quietly announced the company's latest moonshot: a startup designed to improve life in cities to be led by the former chief executive of L.P.

In a blog post on the company's moribund social network, Google +, Page said Google was launching Sidewalk Labs, a new company that "will focus on improving city life for everyone by developing and incubating urban technologies to address issues like cost of living, efficient transportation and energy usage."

Sidewalk Labs will be led by Dan Doctoroff, the former CEO of Bloomberg and a former deputy mayor of economic development and rebuilding for New York City.

"Every time I talk with Dan I feel an amazing sense of opportunity because of all the ways technology can help transform cities to be more livable, flexible and vibrant," Page wrote. He compared Sidewalk Labs to Calico, the well-financed life sciences company Google launched in 2013, and to Google X, its factory of "moonshots" like self-driving cars and a fleet of high-altitude balloons for Internet service. But while both those endeavors have significant financial backing, Page called Sidewalk Labs a "relatively modest investment."