The Yellow Light: Systems-Design for Human Dysfunction
Beware. This post is especially nerdy.
Yesterday I was driving my 9 year old son Andrew home from soccer practice. As we went through an intersection he said to me, “I think yellow lights are useless. Everyone speeds up when they see them instead of slowing down.” So I said to him, “yeah but there’s a timer on the lights for the cars on the intersecting road. So I think the people who designed the traffic lights took that into account.” And that got me going off in all these “design-nerd” tangents in my mind. I started thinking about all of the trial and error that must have gone into the evolution of traffic light design. Then I thought about who must have designed the first traffic light... It was a 1920 Detroit policeman by the name of William Potts. If you really want to “nerd out” read this article about the history of traffic lights. Apparently the original intent of the design was merely to inform people that the light was about to change. But I think today, over 100 years later, we’ve got a few additional interpretations going on as we interact with this ubiquitous invention.
Red means “stop”, green means “go”. This is definitive. And, according to Andrew, yellow means “slow down”. So maybe he’s right but maybe he’s wrong. I’m sure there’s a lot of people on the road who would totally agree with Andrew on this. I think you could also say yellow technically means “proceed with caution”. In any event, to Andrew’s point, it’s fair to say that the rule for yellow is not to “risk an accident by hitting the gas and getting through the intersection as quickly as possible”. But, indeed, people do this all the time. I have to confess I do it here and there myself (maybe Andrew’s even observed this).
Ok, so why in the world would I look at this mundane thing and find the inspiration to write about it in today’s blog? Well, the truth is I wanted to to take a look at some of the flaws. Thinking about design flaws are chiefly how designs are improved upon. And it’s a good mental exercise for any designer.
My conclusion is that the flaws are not in the design but in the interpretations and reactions to the design. The original William Potts design is pretty brilliant. It’s lasted 101 years after all. But sometimes a brilliant design just isn’t enough to get the job done and it needs some help. It needs reinforcement… it needs… drum roll… design thinking!!… Enter the programmed delay at intersection traffic lights. You know the kind. You’re at the light, it turns yellow, you stop, it turns red, you sit looking. And then you notice after several seconds the that light on the intersecting road turns green. But you were there for a good 5 seconds or so before that happened. There was actually a short span of time where all lights at the intersection were red. There is design-thinking here. This allows for all cars to clear the intersection before any other cars make their way in. This design actually accounts for that individual who races to get through before yellow turns to red and in turns fails miserably (and thus puts lives in danger). The irrational nature of human beings is conquered once again by design thinking. Is this nerdy? Sure. But guess what. Lives have been saved because of this. I’m sure multitudes of lives. And that’s pretty inspirational if you ask me.
Pretty cool.
Chalk one up for nerdy design thinkers!!!