Researchers asked 2,000 study participants to choose the moral course of action in accident scenarios where the number of vehicle passengers and at-risk pedestrians varied. Motor vehicle accidents caused nearly 40,000 traffic fatalities and 4.5 million serious injuries in the United States in 2015, and 90 percent of those accidents were due to human error. Remove the human component with self-driving vehicles, and many of those accidents could be preventable. Instead, computer-driven cars will face moral dilemmas where they must choose between two bad outcomes: Place a passenger in danger to save a pedestrian or vice versa. A new study argues that how these vehicles respond to ethical dilemmas could dictate their public safety and widespread adoption by consumers.