Well the first thing, I got me a fuel pump
— Johnny Cash, One Piece At A Time
Above is an icon of a petrol pump, which you will see on pretty much every car dashboard. Most (not all) modern-ish cars also have a little triangle next to the petrol pump icon. That little triangle points either right or left: it is showing on which side of the car the hole for putting petrol in is. So the one above (with the triangle arrow thing helpfully coloured in red) means that the fuel pipe is on the left-hand-side of the car.
I did not know this. It turns out that lots and lots of other people do not know this either. The world seems to be divided into three roughly equal-sized classes: people who already know this and are amazed that everyone did not; people who did not know this and are amazed; and people who say “my car doesn’t have that, is it a US/UK/EU-only thing?”
There is a lesson here, though. This is, once you know what it means, quite an elegant little solution. Now that you know it, you’ll never pull into a petrol station on the wrong side of the pump ever again. It’s clever, it’s simple, and… half the people in the world don’t know about it. There are, I’m sure, conclusions to be drawn about usability studies, iconography, and so on. I mean, spare a thought for the usability testing team on your project at this moment. How do you test this? If you show someone the icon and say “what does this mean?” most people would (probably) guess correctly. The point here is: once you know that the triangle means something, it’s reasonably easy to guess what the something is. But if you don’t know that it’s there for a reason, a goodly proportion of people (myself included) will never think to wonder about it, and so won’t ever learn that it represents a useful bit of information. This has ramifications for how you yourself do usability testing for the things you make.
This has been a party political broadcast on behalf of the “semiotics is useless if you don’t realise there’s a meaning there to discuss, Umberto Eco” party.
‘tard.
First time I saw one, I thought to myself “What’s that odd little triangle doing there? Oh wait – of course!” Can’t believe you’ve been ignoring it all this time.
Add a fourth (rather small but growing) class: Those who know that for cars that don’t have the triangle, the side of the hole for putting petrol in is shown by the pointer of the tachometer.
So the triangle here is merely a effort to visualize an information, that’s already visualized, in a more conspicuous way. You’re free to draw your own conclusions….
I’m one of those people who are surprised that people don’t know this. Then again, I’ve spent 5 minutes scanning through the manual of every car that I owned. You get lots of good tips sometimes and it’s worth doing so no matter what kind of driver/person you are. That’s usually the way you’re supposed to know these things. I know many people don’t like reading manuals, but sheesh, a few minutes investment is worth while considering the time that that knowledge could save you in the future.
I didn’t know this, but I’m one of the fifth group – those who just use the nearest free pump, never mind what side it’s on
I did not know this and I don’t remember seeing it, but I know on which side of my car the hole is.
Manual for my car is more than 300 pages long. I skimmed it, but even that took way more than 5 minutes and I sure as hell didn’t remember everything in it.
The pointer of the tachometer? So if you push down the accelerator all the way, the fuel pipe magically migrates to the other side of the car?
There’s actually another convention, at least in .au – the pump handle on the icon is on the same side as the fuel cap.
This is even less obvious than the arrow
raof: and also sadly untrue
http://www.hoax-slayer.com/fuel-tank-filler-icon-secret.shtml describes how the “pump handle is on the same side as the fuel filler cap” thing is tragically not the case, although I suppose it may actually be true in Oz? I’d recommend checking a few friends’ cars before retailing the story, though. I think the arrow is right because you have to go to extra effort to add it 
Heh. It’s worked for the n=3 sample I’ve actually checked it for
There is also the Costco solution where they make sure the hose can reach either side of the car so it is immaterial which side of the car the cap is. It is also worth pointing out that the information about which side is only useful when you are refuelling a car that isn’t yours since you know for your own car. How often do people drive other cars and how often do they refuel them? (Frequent renters will know about this.)
I’m in the people who did not know this camp and this is the reason why: http://www.cytrap.eu/files/HowToComMetrics/2008/image/10/2008-10-16-mini-tacho-dashboard.jpg
My Mini dashboard does not feature the little arrow (and no, Roger, not everyone can remember which side the fuel cap is on, even on their own car – me for example).
But you’re right, in that if one doesn’t notice a thing is there, one can’t intuit what that thing may be for.
I did not know this. While looking at the picture, I did not realize the red arrow meant anything. It is quite likely that if you had asked me beforehand what it means, I would not have guessed. I often drive, and refuel, two different cars, with opposite refueling sides, and for some reason I cannot learn which is which. So thanks, you just improved my life a little bit. And yes, much respect for our colleagues who deal with this nasty usability stuff.