Autonomous vehicles navigate using motion sensors, multiple radar, sonar, lasers and artificial intelligence (AI) cameras. (AI actually refers to machine learning because there is no such thing as artificial intelligence quite yet; optical character sign readers and image recognition take repetition and practice, but can be learned and programmed for responses.) And not all carmakers are using the same combination of sensors or software. The cameras on a car manufactured by Tesla Inc. can read traffic signs and identify objects, for example, along with predictive analytics and high-speed computer chips allowing reactions in a few milliseconds. Tesla vehicles have had some autonomous driving features — cars that can stay in their lane and between cars in front and rear — since 2014, but the company has not pulled the trigger on full-blown autonomous driving except in test mode. The reason is, Tesla feels autonomously driven cars must be far safer than humans, not merely slightly