Choosing who your car should kill: autonomy study asks the hardest question

Who would you choose for your car to kill?
Andrew Chesterton

Contributing Journalist

3 min read

A landmark study has tackled one of the biggest philosophical questions surrounding autonomous cars; exactly who the vehicle should choose to crash into in the case of an unavoidable accent.

For as long as autonomous cars have been a part of the motoring conversation, people have struggled with the concept of exactly how the vehicle's brain will behave in a potentially fatal emergency.

The most popular imagined scenario goes something like this; if your autonomous car is driving over a bridge and a group of children step out in front of you, how should the car be programmed to respond? Should it run into the pedestrians, almost certainly killing more than one person, or should it swerve left or right and launch off the edge of bridge, taking you with it, but only costing a single human life instead of several?

Now a major International study, published in Nature, has asked that very question, and the answers might surprise you.

Researchers from the Massachusetts Institute of Technology launched a global ethics quiz which asked people around the world who they though a car should save in the case of an unavoidable accident. The quiz got more than two million responses, and while some answers were predictable (like saving people instead of pets), some surprising new trends emerged.

People showed a preference for saving athletic people over those who are overweight, for example, and even saving executives or white-collar workers over people perceived as homeless. Pregnant women and children were seen as too great a sacrifice, with respondents choosing to crash into older people instead.

"Before we allow our cars to make ethical decisions, we need to have a global conversation to express our preferences to the companies that will design moral algorithms, and to the policymakers that will regulate them," the study reads. "The Moral Machine was deployed to initiate such a conversation, and millions of people weighed in from around the world."

But people working in vehicle autonomy argue studies like these focus on hugely unlikely scenarios, with the most common vehicle response to any situation almost always going to be coming to a complete stop as quickly as possible, as opposed to swerving into anything.

“It takes some of the intellectual intrigue out of the problem, but the answer is almost always ‘slam on the brakes’,” Google engineer Andrew Chatham told The Guardian. “You’re much more confident about things directly in front of you, just because of how the system works, but also your control is much more precise by slamming on the brakes than trying to swerve into anything.

"It would need to be a pretty extreme situation before that becomes anything other than the correct answer.”

What do you think of our autonomous future? Tell us in the comments below.

Andrew Chesterton

Contributing Journalist

CarsGuide contributing journalist Andrew Chesterton is an award-winning Australian automotive reporter with more than 20 years of experience across newspapers, magazines, digital publishing and automotive corporate communications. Andrew began his journalism career at Sydney’s The Daily Telegraph and The Sunday Telegraph, reporting across business, courts, crime, property and state politics before moving into automotive journalism. He joined Top Gear Australia as its online editor in 2008, later being appointed editor of Top Gear New Zealand. He subsequently worked as an assistant editor during the Australian launch of the Daily Mail Australia, and as communications manager at FCA Australia, now Stellantis. His experience on both sides of the media industry gives him an unrivalled understanding of the automotive industry, and the relationship between car manufacturers, the media, and Australian consumers. Andrew’s work has appeared across leading automotive, news, business, luxury, travel and lifestyle publications, including CarsGuide, EV Central, DMARGE, The Sydney Morning Herald, Marie Claire, Top Gear, GQ Australia, The Australian, WISH Magazine, Boss Hunting, The West Australian, The Nightly, Women’s Day Australia, Carsales, NRMA, Men’s Health, CEO Magazine, Australian Financial Review and more.   Andrew specialises in industry news, vehicle reviews, policy,  performance and luxury cars, electric vehicles, automotive technology, EVs hybrid and plug-in hybrids, and the broader Australian new-car marketplace. In 2025, Andrew was named Newspress Australia News Journalist of the Year and was a finalist for the overall Journalist of the Year award. Earlier honours include Website of the Year wins at the Australian Magazine Awards and ACP Awards, the ACP Rising Star Award and recognition in the Bauer Media and News Ltd journalism awards. Expertise Electric, hybrid and plug-in hybrid vehicles Performance, luxury and supercars New-car reviews and road testing Australian automotive industry and new-car sales Chinese automotive brands and emerging manufacturers Utes, SUVs and family vehicles Automotive technology Policy Awards 2025 Newspress Australia News Journalist of the Year Featured Publications CarsGuide EV Central DMARGE The Sydney Morning Herald Marie Claire Top Gear GQ Australia The Australian WISH Magazine Boss Hunting The West Australian The Nightly Women’s Day Australia Carsales NRMA Men’s Health CEO Magazine Australian Financial Review The Daily Telegraph The Sunday Telegraph Note: The author, Andrew Chesterton, is a co-owner of Smart As Media, a content agency and media distribution service with a number automotive brands among its clients. When producing content for CarsGuide, he does so in accordance with the CarsGuide Editorial Guidelines and Code of Ethics, and the views and opinions expressed in this article are solely those of the author.
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