traffic lights + user interface design

The wonderful Google Reader showed me an idea for traffic light design.  There are links to three other designs in that story.  It got me thinking a bit, because it’s not exactly HCI because there’s no computer, but it’s the same thing you’d do in HCI.

Aside from one design, they strike me as designs that favor technology for technology’s sake.  The other design is maybe a slight improvement in learnability for those with problematic color blindness.

Getting back to the original link, the hourglass design has several problems.  For one, you need to design both for good and poor eyesight.  The animation is too smooth – it needs to be more discrete to be able to design for those conditions.  The hourglass metaphor doesn’t seem to add anything.  If we were aliens or newborn children, perhaps the hourglass metaphor would be helpful for learnability.  Using the same animation for red/green seems like a bad idea – if I recall correctly, the one color blind person I know has trouble distinguishing between the red and green used in existing traffic lights.

The numbers on the display are very helpful and would improve usability for certain people.  The rule I learned from the NJ driver’s manual was that when the light turns yellow, you’re required to stop if you can do so safely.  In contrast, people will only stop if there’s no chance of running a red light.  In that sense it can be helpful to have a number on a yellow light.

As an aside, many areas already have a way to get a countdown for a red light (for when it’ll turn green next).  Look at the crosswalk signs.  When those start flashing the countdown (if any) will tell you when to expect the lights to transition.

I’ll probably post some NLP researchy things soon, but I had to write that out before I forgot.


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