(An Ofo shared bike in Seattle Photo/GeekWire)

Chinese bike-sharing operator Ofo introduced 1,000 of its signature yellow bikes to the U.S. city of Seattle on Aug. 18, after local authorities gave their okay, making Seattle home to the biggest cluster of dockless shared bikes in America.

Seattle is the first American city to sanction dockless bike sharing. Ofo’s bikes are expected to roll out in the city as part of a six-month pilot program, along with Limebike’s green bikes and Spin’s orange bikes.

Located in the state of Washington, Seattle is not the ideal choice for shared bikes. According to Seattle Times, local-based bike-sharing company Pronto ended its 3-year operation on Mar. 31, because of the city’s hilly terrain, rainy weather, mandatory helmet law, and urban planning with few protected bikeways.

Shared bikes were successfully introduced thanks to support from Seattle Department of Transportation, who introduced new rules in late June for where bikes can and cannot be parked, and set benchmarks for getting broken bikes off the street.

In addition, the fleet size of shared bikes could not exceed 500. During the pilot program, the fleet size can expand to 1,000, then to 2,000 and eventually will be unlimited. The measures were put in place to counter fears that Seattle would end up with a huge pile of broken bikes.

Lin Wenxin, vice president of Ofo USA, said safety promotions were underway, such as activities to give out free helmets and app notifications to remind users to wear helmets.