Autonomous vehicle start-ups have raised billions of dollars based on promises to develop cars that can drive themselves. But it would seem that some experts and industry executives are beginning to doubt the possibility of autonomous vehicles ever being able to operate without some form of human supervision. “The problem with truly autonomous vehicles is that robot drivers are just not as quick as human drivers in assessing situations and making decisions as they drive,” according to Reuters Senior Correspondent and transport specialist, Nick Carey. “It’s very difficult for machines to view t…