Zipcar is making a bigger claim to downtown with the opening of an office and additional parking spots, including some outside the train station.

"We're excited to be here, our fifteenth metropolitan market," said Mark Norman, president of the world's largest car sharing company at a ceremony with Mayor Angel Taveras at Kennedy Plaza Thursday.

Zipcar already has 19 cars and spaces in Providence, having started with two cars at Brown University in 2005. With Thursday's announcement, it will add six additional parking spots immediately, bringing the downtown total to 25.

And it will add 10 more when it opens its office in the fall. It currently has offices in 14 cities.

"Zipcar makes Providence a cleaner, greener city," said Taveras, adding that it alleviates pressure on parking spots given studies finding one shared-car takes 15 owned-cars off the road. "It makes it easy and affordable to get around the city."