Koopman believes that the safety hype around AVs is exaggerated. “There’s nothing I’ve seen showing whether AVs will be safer than humans in the short to medium term,” he says. “Machine learning is brittle, and it struggles with things it hasn’t seen before.” Especially in cities, seeing something unprecedented — like a woman chasing a duck with a broom, a scene a Google car apparently encountered — is quite common. (Notably, self-driving trucks on highways may be more viable than self-driving cars in cities because of the simpler road environment.) And system errors have already proved deadly: A prototype AV from Uber struck and killed Elaine Herzberg while she walked her bicycle across an avenue in Tempe, Ariz., in 2018. Afterward, Arizona’s governor suspended Uber’s ability to test its autonomous technology there, and two years later, the company sold its self-driving unit to Aurora, a start-up.