Uber is reportedly thinking of branching out from four-wheel transportation to the two-wheeled variety.

The ride-hailing service plans to join San Francisco's scooter craze, submitting an application for the city's upcoming pilot program, Axios reported Thursday. Under a city law that went into effect Monday, any company that wants to offer on-demand dockless scooters in San Francisco must apply for a permit.

Uber didn't immediate respond to a request for comment, but Uber CEO Dara Khosrowshahi hinted at such an idea last week at Recode's Code Conference in Southern California, saying the company is "thinking about alternative forms of transport." When pressed for specifics, he conceded, "Bikes, perhaps scooters."

With the move, Uber will be joining the scooter free-for-all that has inundated its hometown during the past two months. Three companies -- Bird, Lime and Spin -- unloaded their rentable e-scooters across the city in March and almost instantly, hundreds of scooters swarmed the sidewalks. The three companies say they're solving a "last-mile" transportation problem, giving commuters an easy and convenient way to zip around the city while helping ease street congestion and smog.

But residents complained that riders didn't follow the laws of the road and endangered pedestrians by riding on sidewalks and leaving the scooters wherever they felt like it -- blocking parking spots, bike racks and wheelchair accesses.

San Francisco's scooter law allows for a 12-month pilot program for the city to see whether the scooters serve public interest. Under the program, up to five companies can apply for the permits. A total of 1,250 scooters may be permitted in the first six months. If that number of scooters works, the cap could increase to 2,500.

To get the permits, each company has to demonstrate that it'll provide user education on sidewalk riding and parking, be insured, and have a privacy policy to safeguard users' information. The companies also need to share trip data with the city and offer a plan for low-income riders.

CNET's Dara Kerr contributed to this report.

The Smartest Stuff: Innovators are thinking up new ways to make you -- and the world around you -- smarter.

CNET Magazine: Check out a sampling of the stories you'll find in CNET's newsstand edition.