Preventing human mistakes through clever design

Yesterday, when I was standing in a drive-through queue, I got confused for a second. In my car, there were two sets of buttons on each side of the steering wheel: on the left were cruise controls and function keys, like increase and decrease speed and distance between cars, and on the right were media controls—play next or previous track, increase and decrease volume and others.

While I was waiting, I wanted to change the track to the next one, so I clicked right button on the right side of the steering wheel, but nothing happened. I clicked again, yet car was still playing the same song. Only then I realised that I was clicking cruise control function key instead of a media key, because steering wheel was turned upside down (I was standing on the corner of the queue, turning left).

One reason why it took me a second to realise my mistake was that on both—cruise control and media—keys had triangle shape icons. Only difference between them was that triangles on media keys had one small line on the corner (the universal next and previous track icon).

After feeling stupid for a second, it got me thinking why I made this mistake in the first place. One reason was that triangles on both sets of keys were very similar, so if I was a car maker, my initial idea would be to make them more distinguishable. But what if people would be allowed to do this mistake? If car is standing still, there is no use for cruise controls. What if triangle-shaped cruise function buttons would replicate media controls and change music track as well when pressed? With this design decision, I might not even notice my mistake, but car would understand my intention and invoke appropriate action.

Would this solution be worth it? It’s hard to tell without proper research and testing, but it’s always beneficial to think about these things if you’re a product maker.

On a related note, I recently read book on this sort of thing called “The Design of Everyday Things” by Don Norman—it’s probably the reason why it prompted me to think about this problem instead of feeling like an idiot and just moving on. Highly recommend reading it.

Rolandas Barysas
Hello, my name is Rolandas Barysas. I write software for a living, splitting my time between freelancing and personal projects.