Photo by Elvert Barnes.

The cars are small, but their effect on D.C.’s roadways is mighty. For each diminutive blue-and-white car2go vehicle you see zooming around town, there are seven fewer personal cars on the road, according to a study by UC Berkeley’s Transportation Sustainability Research Center.

In total, that means 4,600 fewer vehicles in D.C., either because owners sold their cars or car2go users chose not to buy one in the first place, the researchers found. In other cities, the effect was even more pronounced. In Calgary, for example the service took an estimated 11 cars of the road per car2go vehicle, for a total of 6,058.

UC Berkeley’s Transportation Sustainability Research Center

Other tidbits from the study include that Washington car2go users average trips of 3.4 miles. About a quarter of users said they take public transit less frequently, while 37 percent reported using ride-hailing apps like Uber and Lyft less frequently and 57 percent said they now use taxis less often.