If you've spotted bright green or yellow bikes parked around Aurora lately, there's a good reason.

They're part of a dockless bike-share system that got started in October. Aurora approved three permits for apps LimeBike, Ofo and Spin. The companies let you pick up a bike and drop it off anywhere (with some restrictions).

Rides cost a dollar every 30 minutes or an hour depending on which app you choose.

Between October and November, 6,000 rides were taken between the three companies.

Despite the early success, Aurora does acknowledge some problems, like people parking the bikes in the middle of sidewalks.

"It's a young program. There's still a lot of things that we can work through and improve at, one being parking, better parking management of bikes and just giving riders a little bit more education and assistance on how to use the bikes and where to leave them," Planner Brenden Paradies said.

There is a FAQ section up on Aurora's website about the bikes.