car2go announced Tuesday that after nine years, it has reached 1 million members in North America and will offer consumers free membership and drive credits through the end of December to celebrate.

The car2go app, which first launched in Germany in 2008, provides consumers who live in growing urban areas with a carsharing network of eco-friendly Mercedes-Benz and smart vehicles.

The service was first introduced to North America through a successful pilot project with the city of Austin, Texas in 2009. car2go started with just 200 cars and has since expanded operations to 11 cities in the U.S. and Canada, according to the company.

“Today marks a monumental achievement for car2go and for carsharing in North America,” car2go North America chief executive officer Paul DeLong said in a news release. “One million North Americans who carshare with car2go is proof that carsharing is no longer a novel idea or an experiment. Carsharing is now a proven transportation tool that positively impacts mobility and quality of life in cities all over the world.”

In addition to improving city air quality, car2go is also designed to help reduce road congestion.

The company said each car2go removed up to 11 other vehicles from city streets and prevented up to 14 metric tons of greenhouse gases from polluting city air, according to a 2016 U.C. Berkeley study.

To take advantage of car2go’s limited free membership and drive credits offering, prospective members must use the promo code: “THANKSAMILLION” when signing on.