The self-driving Ford cars Uber showed off in May will also be part of this trial in Pittsburgh.
Rides in the Uber's driverless cars will be free at the beginning, but they also can not be specifically requested - instead, they will deploy at random through the app's normal ride request function.
Uber's moves reflect its eagerness to advance self-driving technology. They will be accompanied by human supervisors for now.
Kalanick sees self-driving cars as "existential" for his firm, which was most recently valued at more than $62 billion.
While these rides will be free for anyone that wants one, it doesn't sound quite as relaxing as the average Uber ride.
The auto company has pledged to mass-produce "fully autonomous vehicles in commercial operation for a ride-hailing or ride-sharing service beginning in 2021".
"If that sounds like a big deal - well, it is", Uber CEO Travis Kalanick said in a statement.
He said that we have got to be laser-focused on getting this to market, because it is not a side project for us. "This is everything. This is all the marbles for Uber".
Uber Chief Executive Travis Kalanick said the technology is necessary to lower the cost of ride hailing and vehicle ownership, even if it means the future loss of jobs among Uber's 1.5 million active drivers world-wide.
All up, the partners will contribute a total of US$300 million ($390 million) to the project. Both companies will use the same base vehicles for the next step in their autonomous driving strategies. "It is unconscionable for them to offer rides to passengers at this stage".
Taxi drivers won't need to worry about being out of work just yet though as even these autonomous cars will have a person sat behind the wheel, just in case.
He predicted that drivers will often have to intervene in Pittsburgh, with its winding, hilly roads and vast number of bridges.
As the auto moves, it collects data, and then using a large, liquid-cooled computer in the trunk, it assimilates a real time map of the area it is driving through. The PR fallout from the crash of a semi-autonomous Tesla back in May has unsettled many. The cars will only go limited distances within the city. Standing at a bus stop, Anthony Fielder of the suburb of Carnegie was open to the idea.