San Francisco

TESLA Inc started testing four self-driving cars on California's public roads late last year, a milestone for chief executive officer Elon Musk who has promised to demonstrate an autonomous road trip from Los Angeles to New York by the end of 2017.

The carmaker's autonomous vehicles travelled a total of 550 miles (885km) on California public roads in October and November 2016 and reported 182 "disengagements", or episodes when a human driver needs to take control to avoid an accident or respond to technical problems, according to a filing with the California Department of Motor Vehicles.