Feb 29 Japan's Robot Taxi aims to forge partnerships with carmakers to develop a driverless taxi service in time for the 2020 Olympics, the technology company said, holding its first tests on public roads and joining a global race to develop self-driving cars. The joint venture between gaming software maker DeNA Co and robotics developer ZMP has set the 2020 Games in Tokyo as a target to develop software to operate driverless cars and an online service to ferry athletes and tourists between Olympic venues and the city's transport hubs.