People reluctant to use self-driving cars, survey shows

Autonomous vehicles are going to save us from traffic, emissions, and inefficient models of car ownership. But while songs of praise for self-driving cars are regularly sung in Silicon Valley, does the public really want them?

That’s what my student Charlie Hewitt, and collaborators Ioannis Politis and Theocharis Amanatidis set out to study. We decided to conduct a public opinion survey to find out.

However, we first had to solve two problems.

  1. When Charlie started his work, there were no existing surveys designed specifically around autonomous vehicles. We had some surveys for technology acceptance in general, and some for cars, which are a good start. So we combined those and introduced some additional information. This resulted in the creation of a new survey designed specifically for autonomous vehicles. We called it the Autonomous Vehicle Acceptance Model, or AVAM for short.
  2. When people think of self-driving cars, they generally picture a futuristic pod with no steering wheel or controls, that they just step into and get magically transported to their destination. However, the auto industry differentiates between six levels of autonomy. Previous studies had attempted to get people’s attitudes to each of these levels, but it turns out people can’t picture these different levels of autonomy very well, and don’t understand how they differ. So, Charlie created short descriptions to explain the differences between them. These vignettes are a key part of the AVAM, because they help the general public understand the implications of different levels of autonomy.

Here are the six levels of autonomous vehicles as described in our survey:

  • Level 0: No Driving Automation. Your car requires you to fully control steering, acceleration/deceleration and gear changes at all times while driving. No autonomous functionality is present.
  • Level 1: Driver Assistance. Your car requires you to control steering and acceleration/deceleration on most roads. On large, multi-lane highways the vehicle is equipped with cruise-control which can maintain your desired speed, or match the speed of the vehicle to that of the vehicle in front, autonomously. You are required to maintain control of the steering at all times.
  • Level 2: Partial Driving Automation. Your car requires you to control steering and  acceleration/deceleration on most roads. On large, multi-lane highways the vehicle is equipped with cruise-control which can maintain your desired speed, or match the speed of the vehicle to that of the vehicle in front, autonomously. The car can also follow the highway’s lane markings and change between lanes autonomously, but may require you to retake control with little or no warning in emergency situations.
  • Level 3: Conditional Driving Automation. Your car can drive partially autonomously on large, multi-lane highways. You must manually steer and accelerate/decelerate when on minor roads, but upon entering a highway the car can take control and steer, accelerate/decelerate and switch lanes as appropriate. The car is aware of potential emergency situations, but if it encounters a confusing situation which it cannot handle autonomously then you will be alerted and must retake control within a few seconds. Upon reaching the exit of the highway the car indicates that you must retake control of the steering and speed control.
  • Level 4: High Driving Automation. Your car can drive fully autonomously only on large, multi-lane highways. You must manually steer and accelerate/decelerate when on minor roads, but upon entering a highway the car can take full control and can steer, accelerate/decelerate and switch lanes as appropriate. The car does not rely on your input at all while on the highway. Upon reaching the exit of the highway the car indicates that you must retake control of the steering and speed control.
  • Level 5: Full Driving Automation. Your car is fully autonomous. You are able to get into the car and instruct it where you would like to travel to, the car then carries out your desired route with no further interaction required from you. There are no steering or speed controls as driving occurs without any interaction from you.

Before you read on, think about each of those levels. What do you think are the advantages and disadvantages of each? Which would you be comfortable with and why?

We sent our survey to 187 drivers recruited from across the USA, and here’s what we found:

Result 1: our respondents were not ready to accept autonomous vehicles.

We found that on many measures, people report a lower acceptance of higher automation levels. People perceive higher autonomy levels as being less safe, they report lower intent to use them, and higher anxiety with higher autonomy levels.

We compared some of the results with those from an earlier study, conducted in 2014. We had to make some simplifying assumptions, as the 2014 study wasn’t conducted with the AVAM. However, we still found that our results were mostly similar: both studies found that people (unsurprisingly) expected to have to do less as the level of autonomy increased. Both studies also found that people showed lower intent to use higher autonomy vehicles, and poorer general attitude towards higher autonomy. Self-driving cars seem to be suffering in public opinion!

Result 2: the biggest leap in user perception comes with full autonomy.

We asked people how much they would expect to have to use their hands, feet and eyes while using a vehicle at each level of autonomy. Even though vehicles at the intermediate levels of autonomy (3 and 4) can do significantly more than levels 1 and 2, people did not perceive the higher levels as requiring significantly less engagement. However, at level 5 (full autonomy), there was a dramatic drop in expected engagement. This was an interesting and new finding (albeit not entirely surprising). One explanation for this is that people only really perceive two levels of autonomy: partial and full, and don’t really care about the minor differences in experience with different levels of partial autonomy.

All in all, we were fascinated to learn about people’s attitudes to self-driving cars. Despite the enthusiasm displayed by the tech media, there seems to be a consistent concern around their safety and reluctance to adopt amongst the general public. Even if self-driving cars really do end up being safer and better in many other ways than regular cars, automakers will still face this challenge of public perception.

And now, a summary poem:

The iron beast has come alive,
We do not want it, do not want it
Its promises we do not prize
It does not do as we see fit

Only when we can rely
On iron beast with its own eye
Only then will we concede
And disaffection yield to need

If you’re interested in using our questionnaire or our data, please reach out! I’d love to help you build on our research.

Want to learn more about our study? Read it here (click to download PDF) or see the publication details below:

Charlie Hewitt, Ioannis Politis, Theocharis Amanatidis, and Advait Sarkar. 2019. Assessing public perception of self-driving cars: the autonomous vehicle acceptance model. In Proceedings of the 24th International Conference on Intelligent User Interfaces (IUI ’19). ACM, New York, NY, USA, 518-527. DOI: https://doi.org/10.1145/3301275.3302268

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