Toyota Motor Corporation, displays the "e-Palette", a new fully self-driving electric concept vehicle designed to be used for ride hailing, parcel delivery services and other uses at CES in Las Vegas, Nevada, U.S., January 8, 2018. Image for illustrative purposes.

Japan's SoftBank and Mitsubishi Estate demonstrate a self-driving bus named Navya Arma, during the demonstration event in what organisers say will be Tokyo's first test on public roads, in Tokyo, Japan, December 22, 2017.

Japan's SoftBank and Mitsubishi Estate demonstrate a self-driving bus named Navya Arma, during the demonstration event in what organisers say will be Tokyo's first test on public roads, in Tokyo, Japan, December 22, 2017.

Toyota Motor Corporation, displays the "e-Palette", a new fully self-driving electric concept vehicle designed to be used for ride hailing, parcel delivery services and other uses at CES in Las Vegas, Nevada, U.S., January 8, 2018.

A Ford Fusion hybrid, Level 4 autonomous vehicle, used by Ford Motor and Domino's Pizza to test a self-driving pizza delivery car in Michigan, is displayed during Press Days of the North American International Auto Show at Cobo Center in Detroit, Michigan, U.S., January 16, 2018.

Japan's SoftBank and Mitsubishi Estate demonstrate a self-driving bus named Navya Arma, during the demonstration event in what organisers say will be Tokyo's first test on public roads, in Tokyo, Japan, December 22, 2017.

Toyota Motor Corporation, displays the "e-Palette", a new fully self-driving electric concept vehicle designed to be used for ride hailing, parcel delivery services and other uses at CES in Las Vegas, Nevada, U.S., January 8, 2018. REUTERS/Rick Wilking

Japan's SoftBank and Mitsubishi Estate demonstrate a self-driving bus named Navya Arma, during the demonstration event in what organisers say will be Tokyo's first test on public roads, in Tokyo, Japan, December 22, 2017.

A Ford Fusion hybrid, Level 4 autonomous vehicle, used by Ford Motor and Domino's Pizza to test a self-driving pizza delivery car in Michigan, is displayed during Press Days of the North American International Auto Show at Cobo Center in Detroit, Michigan, U.S., January 16, 2018.