In Austin, Texas, Tesla has taken a consequential step in the long march toward autonomous transportation, launching its driverless Cybercab taxi service on public roads — only to find federal regulators arriving in close step behind. The National Highway Traffic Safety Administration has opened a formal investigation to determine whether the vehicle meets existing safety standards, a move that reflects not suspicion of wrongdoing, but the weight of a society still learning how to govern machines that drive themselves. The moment sits at the intersection of technological ambition and democrati