Study Explores Safety Ethics in Self-Driving Cars

Pedestrian walking on a crosswalkProgrammers of self-driving cars may eventually have to make a choice: protect the lives of multiple pedestrians or a single driver? According to a new study published in Science, most people think self-driving cars should prioritize the lives of multiple people over a single driver—except when they are the driver.

Many cars already have some automatic features, such as automatic braking if an object enters the car’s field of motion. As technology improves, self-driving cars may become available. They could even replace driver-operated vehicles.

Ethics of Self-Driving Cars

Drivers must make decisions about safety every time they enter a car. Is it better to get to work a few minutes early or to not risk a speeding ticket? Should they swerve to avoid hitting an animal or prioritize the safety of the people in the car? Is it better to avoid an accident by veering left and potentially hitting an elderly woman or veering right and potentially hitting a teenager?

Many people have expressed ambivalence about delegating these subjective decisions to machines. To test how people think cars should make safety decisions, researchers conducted six surveys between June and November 2015. Each survey included between 200 and 450 participants recruited through the Amazon Mechanical Turk platform.

The results suggest people generally prioritize the lives of multiple people over a single individual. When forced to confront the demise of a loved one, however, opinions changed.

In one survey, 76% of participants said self-driving cars should sacrifice a single car occupant to save 10 pedestrians. Another survey indicated participants did not think cars should save a single pedestrian if doing so meant killing the car’s passenger. Willingness to sacrifice a passenger steadily increased with the number of pedestrians saved, even when doing so meant sacrificing their own lives.

In one survey, researchers asked participants to imagine a loved one dying in a car accident. People were less willing to sacrifice their loved ones than themselves, expressing reluctance to kill a family member even to save several pedestrians.

When Ethical Dilemmas Become Reality

Though participants generally endorsed utilitarian moral principles, the results changed when they were presented with the practical realities of purchasing a self-driving car. In one survey, participants said they would be less likely to purchase a self-driving car that would kill a passenger or driver to reduce total casualties. Only 50% of participants would buy such a car. When participants were asked to consider that a self-driving car might sacrifice a family member, only 19% said they would make such a purchase.

Respondents to this survey still said they thought it was right for a car to sacrifice one person to save several. This suggests people might endorse certain moral principles in the abstract, but struggle to embrace them in reality. Previous research has found this approach is common in many moral dilemmas, not just those involving self-driving cars.


  1. Bonnefon, J., Shariff, A., & Rahwan, I. (2016). The social dilemma of autonomous vehicles. Science, 352(6293), 1573-1576. doi:10.1126/science.aaf2654
  2. Saxena, R. (2016, June 23). People want other people’s self-driving cars to keep pedestrians safe. Retrieved from

© Copyright 2016 All rights reserved.

The preceding article was solely written by the author named above. Any views and opinions expressed are not necessarily shared by Questions or concerns about the preceding article can be directed to the author or posted as a comment below.

  • Leave a Comment
  • Franklin


    June 28th, 2016 at 11:38 AM

    Forget the ethics, I’m worried about the safety issues!

  • TJ


    June 29th, 2016 at 5:21 AM

    I haven’t thought about this from an ethical point of view at all. I have only thought along the lines of oh this is a pretyy cool invention. But when you boil it down to something that is robotic and computerized, with no room for human thought and emotion, it sort of makes you look at it a little differently.

  • cooper


    June 30th, 2016 at 10:37 AM

    but we all have to admit that this is kinda cool right?

Leave a Comment

By commenting you acknowledge acceptance of's Terms and Conditions of Use.

* Indicates required field.

GoodTherapy uses cookies to personalize content and ads to provide better services for our users and to analyze our traffic. By continuing to use this site you consent to our cookies.