Uber is really serious about carpooling.

On Tuesday, the ride-hailing service announced an incentive-laden rate to San Francisco for users who carpool.

"You're invited to test ride our newest product for South Bay commuters, POOL TO SF. From 6-10am, Monday-Friday, commute on your own time and ride door-to-door for as low as $20," Uber wrote in a blog post on its site.

As part of its carpooling efforts, Uber is also offering rides from Mountain View for $22 and from San Jose for $26 during those same specified windows of time, adding that bringing a friend will only cost an additional $10.

The way Uber's POOL TO SF testing will work is users will select the carpooling option on their slider, enter their pickup address and request. The app will match users with another rider on the way to the city. Uber has even designated POOL pickup zones on a map to fuel the testing and promotion.

This announcement comes after UberPool recently launched in New York City, offering $10 flat fees from below 96 Street in Manhattan. Overall, the company introduced UberPool in the United States last year and in China in October.

Testing the POOL program in busy San Francisco is key. If it's successful there, the company could very well decide to ramp up its carpooling efforts in other prominent cities throughout the country as well. In addition, Uber's carpooling service could bite into — and possibly even threaten — cities' various means of mass transportation with time.