Bright orange, green and yellow bikes are sprouting up all around central D.C. and Silver Spring, with a smattering elsewhere. They go by Jump, Spin, LimeBike, Mobike and ofo (written in all lowercase, to look typographically like a bike symbol).

This is dockless bike sharing, the newest arrow in the region's transportation quiver. You are probably familiar with Capital Bikeshare, the "classic" style of bike sharing with docking stations scattered about. You walk to one, swipe a member key or a credit card and unlock a bike. You ride to another station and drop the bike off. Vans staffed by Capital Bikeshare employees drive around to "rebalance" bikes and minimize empty or full stations.

With dockless bike sharing, the proposition is about the same, just without docking stations. The bikes have a built-in lock with GPS and cellular technology. You find a bike and unlock it using a smartphone app, ride it somewhere else, park it and pull a lever to lock the wheels.

And when I say park it anywhere, I mean anywhere. These bikes don't even need a bike rack (with the exception of Jump, an outlier among the new companies that costs a bit more but offers bikes with electric motors to supplement your pedaling). You simply stand the bike up on its kickstand and lock the wheels.

That technology (and the smartphones that make it possible) is the real innovation here. Classic bike-sharing docks cost about $50,000 each — a massive bargain compared with roads and rails, which cost millions per mile if you're lucky. But no dock costs nothing. Which is why five companies are spending venture capital dollars to offer you $1 (or $2 for electric) bike rides without public funding.

Dockless bike sharing isn't primarily for avid bicyclists, who usually already have their own two wheels. Rather, it's great for the office worker, student or tourist who needs a quick, occasional ride somewhere. Not right by Metro? Long wait for the bus? No parking? No problem — if there's a bike right there. And you don't have to worry about where to put it when you get where you're going.

If successful, dockless bike-sharing technology could help move more people affordably and in less space — the fundamental geometric challenge of transportation. If 10 people on these bikes can fit in the space of one car, that could mean nine fewer cars adding to traffic.

However, there are some pitfalls. DC Sustainable Transportation, a coalition of business, government and advocacy organizations (which I head), has been working on policy recommendations for governments around dockless bike sharing.

The first issue is parking. If you can leave a bike anywhere, that includes really bad places. Right on top of the sidewalk ramps that people with disabilities or pushing strollers use. In the middle of the sidewalk, blocking the way. Inside a Metro station. Down an embankment. Up a tree. And so on.

Some locations aren't a public policy issue; they're just funny. But bikes actually in the way can be. Right now, there aren't many, and you can usually just move them aside. When the numbers increase, as they must to make dockless bike sharing truly valuable, will this become a regular nuisance?

So far, actually, the experience hasn't been that bad. The best place to park these is between tree boxes, in the area between the walking path and the road. When you really think about it, there are a lot of these spaces and they're generally not being used. Further, it will probably make sense to designate a few parking spaces downtown for dockless bike-sharing storage. A lot of bikes serving a lot of people could fit into very few spaces.

The second issue is data. When the public sector runs a transportation system, cities can use the information about ridership and routes to better plan future transportation. As once-public services such as transit or bike sharing turn private, cities should maintain the access to data that helps planning and helps ensure fairness.

The third main policy issue is equity. I'd love to see these services better serve low-density neighborhoods, low-income areas and other places. But it's also possible they will skim the highest-margin riders in downtown areas and leave Capital Bikeshare with the responsibility of serving everyone else.

The DC Sustainable Transportation recommends a system that sets targets for serving diverse geographies. If dockless operators can more innovatively and efficiently, say, provide service to those without credit cards, terrific! Capital Bikeshare has struggled with this, but it does have programs in place. Or, bike sharing could pay fees to cover the public cost of doing so.

I'm excited about the potential for dockless bike sharing. It could help our region move more people efficiently, compactly and affordably alongside the many existing modes of travel (including Capital Bikeshare, which serves an important need). And on a pilot basis, it seems to be working well. With just a few well-thought public policies, it can become a permanent, beneficial part of this region's transportation mix.

David Alpert is executive director of DC Sustainable Transportation and founder and president of Greater Greater Washington.