life or death decisions for autonomous vehicles

Who lives, who dies?

The life-and-death decisions that autonomous vehicles might have to make

28 January 2019

Autonomous vehicles could have to make life-and-death decisions that more than a third of drivers would prefer not to think about until they happen.

More than half (59%*) say that, should they be the 'passenger' in a fully autonomous vehicle, and it had no choice but to crash, it should put them at risk if the alternatives risked more lives according to a survey by the AA.

Surprisingly, more people were willing to put themselves at risk of death if they themselves were the passenger, as opposed to a generic ‘passenger’ travelling in the car (54%).

Busy city centre dual carriageway junction

The AA-Populus Driver Poll of more than 21,000, found that one in 20 felt the vehicle should hit someone else. Respondents had the option to select a collision involving two children who had run into the road, or with two elderly pedestrians walking on the pavement.

Highlighting the difficulty software developers will have over these decisions, many people felt they were unable to determine what action the car should take (40% and 34% respectively).

The reaction time of autonomous vehicles, helped by sensors, cameras and radar systems is likely to be faster than those of a human driver. An autonomous vehicle is also more likely to see potentianl hazards further ahead, and travel within the speed limit.

The question was asked in the context of the ongoing consultation by the Law Commission into Automated Vehicles. The question is a form of “The Trolley Problem**” scenario that challenges ethical decisions in a life or death situation.

In Germany, the ethics for autonomous vehicles makes clear that in the event of an unavoidable collision, any distinction based on personal features, such as age, gender and ethnicity are strictly prohibited****.

Edmund King, AA president says; “Autonomous cars should create opportunities for people who struggle to access consistent forms of mobility, like the elderly and disabled.

“These vehicles will have so much technology that one should never find itself in this kind of situation.

These vehicles will have so much technology that one should never find itself in this kind of situation
Edmund King, AA president

“Of those who could make a choice, a clear majority decided to put themselves in danger perhaps indicating they accept the risks and potential fallibilities of the technology.

“‘The Driverless Dilemma’ is a common question for programmers of autonomous vehicles, but the number of people who avoided giving a definitive answer shows this is a difficult ‘live or let die’ dilemma.

“Drivers and pedestrians will want to know that fully autonomous vehicles have been rigorously tested to ensure fatalities are prevented and scenarios like these are avoided.”


* Populus received 21,039 responses from AA members to its online poll between 15 and 21 January 2019.

** The trolley problem is a thought experiment in ethics. The general form of which is:

“You see a runaway trolley moving toward five tied-up (or otherwise incapacitated) people lying on the tracks. You are standing next to a lever that controls a switch. If you pull the lever, the trolley will be redirected onto a side track, and the five people on the main track will be saved. However, there is a single person lying on the side track. You have two options, but which is the more ethical?:

  1. Do nothing and allow the trolley to kill the five people on the main track.
  2. Pull the lever, diverting the trolley onto the side track where it will kill one person.

The questions we asked:

Q1. Fully automated (autonomous cars) are expected to be much safer than human drivers and will react faster to events, but there may still be times when they have to resolve ethical dilemmas in an instant. Imagine that two children suddenly run into the road in front of an autonomous vehicle that is driving itself carrying a single ‘passenger’ and travelling too fast to stop in time. The vehicle has three basic options each of which is likely to result in at least one fatality, but which should it choose?

  • Swerve right into the back of a parked HGV 54%
  • Prefer not to say 40%
  • Carry straight on, running over the children 5%
  • Swerve left to run into an elderly couple walking on the pavement 1%

Q2. Imagine now that YOU are riding as the sole ‘passenger’ in an autonomous vehicle that is driving itself. Two children suddenly run into the road in front of the vehicle but it is travelling too fast to stop in time. Which of the following choices would you want the autonomous vehicle to make?

  • Swerve right into the back of a parked HGV 59%
  • Prefer not to say 34%
  • Carry straight on, running over the children 4%
  • Swerve left to run into an elderly couple walking on the pavement 2%

Buy breakdown cover

We get more people back on the road than anyone else