Singaporean Sharon Ong’s toddler son, like most kids his age, is fascinated by all modes of transportation. On a recent visit to the resort island of Sentosa, mother and son hopped on and off the monorail, a bus, and the beach tram, saving the latest addition for the last: the Robobus. The self-driving minibus is the first autonomous vehicle accessible to Singapore’s public. Launched in June by China’s WeRide, the brightly colored shuttle takes about 12 minutes to complete a 1.2-kilometer loop w...