Developer nuTonomy invited a select group of people to download their ride hailing app and ride for free in its "robo-taxi", saying it hoped to get feedback ahead of a planned launch of the service in 2018.
"This is really a moment in history that's going to change how cities are built, how we really look at our surroundings," nuTonomy executive Doug Parker told Reuters.
The ongoing trial rides are taking place in Mitsubishi i-MiEv electric vehicles, with an engineer sitting behind the wheel to monitor how the system deals with the road and take control if necessary.
The company has partnered with the Singapore government on the project, and hopes to have 100 taxis working commercially in the Southeast Asian city state by 2018.
NuTonomy is one of several companies racing to launch self-driving vehicles, with new projects or alliances between automakers and technology firms being announced on an almost weekly basis.
Last week, Uber announced it would begin allowing customers in Pittsburgh to summon self-driving cars from within its ride-hailing app, while Ford announced plans to build a fleet of fully automated driverless cars for commercial ride-sharing by 2021. In June it was reported that Uber had held talks with Fiat Chrysler about a potential partnership involving self-driving car technology.
Apple has been the source of many self-driving automobile rumors since last year, but it's now thought the company's first entrance into the vehicle industry likely won't be autonomous, although later generations of its "Apple Car" would probably include the technology.
However, over the summer reports suggested that Apple is taking a "two-prong approach" to its car development, internally known as "Project Titan", and will focus more on creating its own autonomous driving system rather than manufacturing the vehicle.