Chinese electric vehicle (EV) maker Xpeng has begun mass production of autonomous cabs powered by its own chips, likely to mount yet another challenge on Tesla as both companies pursue a leading position in self-driving. Robotaxi has become the latest area where the two firms could go head-to-head, after smart EV and humanoid robot, as the booming development of physical artificial intelligence (AI) technologies intensifies. Guangzhou-based Xpeng said its robotaxis would have level 4 (L4)...