Autonomous vehicle software start-up nuTonomy has beaten Uber in launching the world’s first autonomous taxi trial, by just a few weeks.

The trial allows invited members of the public living in Singapore to hail a free taxi ride, operated by nuTonomy, via their smartphones. The test vehicles operate in a limited 6.5 sq. km. area, with collection and drop-off points in set locations.

The fleet initially has six test taxis, which could be increased to 12 by the end of the year. The fleet includes Renault Zoes and Mitsubishi i-MiEVs that have been modified to include Lidar laser technology, as well as two cameras on the dashboard, scanning for obstacles and traffic light changes. Each car will have a driver ready to take back control should the need arise. A researcher will also be present in the back of the car, monitoring the car’s computers.

Users must have a special invitation from nuTonomy to use the service, and dozens of people are believed to have already signed up to take part in the trial.

The company executive has reportedly said the aim is to have a fully autonomous fleet of taxis in Singapore by 2018. Should the model prove successful, the company hopes to expand this facility beyond Singapore. NuTonomy’s chief operation officer, Doug Parker, reportedly said autonomous taxis could reduce the number of vehicles on Singapore’s roads from 9,00,000 to 3,00,000.

Ride-sharing service Uber is also set to start a trial of self-driving cars in Pittsburgh, USA, in the coming weeks. The service will start with Ford Fusions equipped with self-driving technology and it will be free for users while the trial takes place.

In a press conference, Uber CEO Travis Kalanick said: “This project is a very important step forward in self-driving technology." But he added that a lot of work still has to be done. "We’re catching up fast, but we need to get to number one quickly," he said. "We must be laser-focused on getting this to market because it’s not just a project for us. This is everything.”

Uber also recently announced a deal with Volvo, so it’s expected that the Swedish manufacturer’s vehicles will feature in the Pittsburgh fleet in the future.

Another supplier working on autonomous vehicle software (Delphi) has also been granted permission to begin its technology trials in Singapore at the beginning of next year.