The autonomous Lincoln MKZ started turning left at a Beijing intersection when a speeding truck made a move to pass in front of it. Sensors in the car detected the approach and instantly froze it in place. 

But that put the Lincoln directly in the truck’s path, so Baidu Inc engineer Sun Lei grabbed the steering wheel, spun it to the right and floored the accelerator to get out of harm’s way. The truck zoomed by as Sun’s colleague in the passenger seat calmly took notes on a tablet computer – just another learning exercise for the self-driving fleet being tested around the nation.