On Wednesday, Uber announced a new feature, where riders "wait a few minutes before their trips begin, and then walk a short distance to a nearby spot for pick up and drop off." If that sounds awfully similar to a bus, you’re not entirely wrong.

Uber calls it "Express Pool," an offshoot of an Uber option known as simply, "Pool," which allows Uber riders to save a few bucks by sharing rides (thus usually taking a little more time).

Express Pool, meanwhile, simply calculates what is ostensibly a more efficient route and asks the rider to walk a few minutes away.

When Ars tried it from one residential neighborhood of Oakland to downtown (just a few miles away), it shaved about $1.50 off of what otherwise would have been a $7 Pool ride or an $8.90 UberX ride. By comparison, a local bus ride for the same route is $2.25.

"Walking and waiting help us make more optimal matches and provide better, straighter, faster routes with fewer detours, delivering an even more affordable and consistent option than POOL to consumers," Uber wrote in a blog post on Wednesday morning.

The company says the service has been tested in San Francisco and Boston; it is also available in Los Angeles, San Diego, and Denver as of Wednesday. Miami, Philadelphia and Washington, DC will be added Thursday, with more cities to follow.

"Pool is available in 36 cities globally," Kaitlin Durkosh, an Uber spokeswoman, emailed Ars. "For a shared rides product to be effective and work as intended, we need to have enough riders requesting trips around the same time and traveling to/from the same areas."

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