A Miami courtroom is hearing emotional testimony in a rare federal case scrutinizing Tesla’s driver-assist tech and Elon Musk’s safety claims

A critical voice took the stand Wednesday in the first-ever federal jury trial involving Tesla’s Autopilot system: a safety expert who says the technology is defective and promoted in ways that encourage misuse.

Mary “Missy” Cummings, an engineering professor at George Mason University, told jurors in Miami federal court that the Tesla owner’s manual, which contains critical warnings about how the system