After just three years in business, pay-per-mile car insurance provider Metromile is significantly expanding its office footprint in the city.

The startup, which is keeping its 5k SF space at 292 Townsend, just inked a seven-year deal to tack on 14,400 SF at 690 Folsom. There the company will be the new neighbors of Macys.com and Riverbed. Metromile, which occupies Feb. 1, also will get some snazzy signage on the side of the building soon (check out a preview, above). In addition to insurance, the service offers drivers features like remote diagnoses of a car's mechanical problems and sending automated street sweeping alerts. Dunhill Partners West's Benjamin Osgood repped the Metromile.

Benjamin tells us 690 Folsom is ideal for Metromile (new space above) because of its proximity to Moscone Center and a daily traffic count of more than 20,000 cars. The car insurance business model caters to a growing demographic of consumer like those in S.F. that drive less than 10,000 miles per year, he adds (Metromile claims customers save on average $500 per year by switching to the company's services). CBRE's John Cecconi, Angus Scott and Amanda Emerson repped landlord Boston Properties.