BEIJING -- Beijing authorities are considering measures to regulate the ubiquitous shared bikes that benefited commuters but challenge urban management.

Beijing began to solicit public opinion Friday on a draft rule that will cap the number of shared bikes on the city's streets and promise orderly parking.

The bike-sharing business, which took off in big Chinese cities less than two years ago, allows riders to hire bikes for as little as one yuan (about $15) per hour via a mobile app and drop them off anywhere for the next users.

The service has helped riders evade Beijing's chronic traffic congestion and cut auto emissions, while haphazardly parked bikes have marred the city's image and blocked roads.

The draft rule requires district governments to set an upper limit for shared bikes in their respective jurisdictions. It says parking zones should be established around transportation hubs, shopping areas and office blocks.

Shared bikes must have GPS devices. The city's transport authorities are working on a technical specification.

In addition, the rule forbids children under the age of 12 from riding shared bikes and bans the idea of shared electric bikes "for a while."

Bike-sharing startups, such as Mobike, Ofo and Bluegogo, have put nearly 700,000 two-wheelers in Beijing, securing nearly 11 million users.

There were 18.9 million users of shared bicycles nationwide in 2016. The number is expected to hit 50 million by the end of 2017.