Since my neighborhood Starbucks closed, I have been walking further in the morning to get coffee for Bette and me. A very urban route it is, too. And when I walk on Broadway going west or on Weidler coming back east, I am walking in the same direction as the traffic. That’s how this all came to me.
I can tell without looking at it when the light turns yellow because there is often a sound of acceleration. You can hear it in the engines and in the sound the tires make on the street. If the drivers are slowing down in response to the yellow light, I either don’t hear it or don’t pay attention to it, but if they are accelerating suddenly, I do hear it and I don’t like it.
So, why are there yellow lights  and why do people game them? The yellow lights, called “caution lights” when they were introduced, announce that a time is coming when you are going to be required to stop. The implication is that you should start preparing to stop. Taking your foot off the accelerator and putting in on the brake would be a good idea.
The difficulty is that the drivers don’t want to stop. And, in fact, the law does not require them to stop for a yellow light, only to prepare to stop. If you go through the intersection while the light is yellow—or, let’s be frank, if you get into the intersection while the light is yellow—then you can continue.  So there is a lot of incentive to treat the yellow light as the last phase of the green light. Not what Mr. Potts had in mind.
I asked, above, why people “game” the yellow lights. That might have seemed a curiously restrained question, given that people game every specific standard we know of. I remember an old Nancy and Sluggo comic strip where “the mother” told the two kids to wash their hands to get ready for dinner. They complained that actually, only one hand (each) was dirty and we are to imagine that the mother said to them, “Well, just wash that one then.” In the final frame, we see the two kids at a bathroom basin, cooperatively washing only one hand (each) and Nancy’s comment was, “I’ll bet she thought we couldn’t do it.”
Exactly. That’s how long we have been gaming the system.
The caution light phenomenon is based on the idea that the only thing that is really wrong is going through a red light. Going through an early yellow or a late yellow aren’t really wrong; possibly imprudent. So how much of the yellow can I utilize for my own convenience (late yellow) without doing something really wrong?
That accounts for the acceleration I hear on the street in the morning. People are hurrying to get through the light because a) they are in a hurry and b) it isn’t really wrong. The “caution light” has become a “this offer will expire in just three more seconds” kind of light.
What to do?
I should preface this by saying that I am not proposing it. I am simply working through the very common problem of gaming the caution light. The first element is that the yellow light is, for all practical purposes, of a known duration.  The second is that the penalty for going through a red light (and getting caught at it) is relatively mild. It is not, for instance, loss of your driver’s license.
So we could, just as a way of restoring the “caution” function to the yellow lights, make the duration of any given yellow light variable.  This means that speeding up to “make the light” would be a very risky thing to do. It is risky in the sense that you would have no rational basis, not even an experiential basis, for calculating whether your attempt to “make the light” would be successful.
That probably wouldn’t do the job by itself, so I would go to the other part of the program and make the detection of the violation certain and the punishment substantial. Cameras at every intersection that has a three-color traffic light would be necessary. They would record every car in the intersection while the light is red and automatically send the notification to the driver. “Your license has just been cancelled” or “This is your second of the three allowable infractions before your license is cancelled.” Whatever kind of penalty the policymakers decided on, provided that the detection and reporting of this act of “un-caution” is certain.
I think that would do the job. It might not be a job worth doing, of course, but it does do the one thing I was hoping to do here, which is to restore the “caution” meaning to the yellow traffic light.
I am reminded in this context, of a forgettable scene from a forgettable movie called Starman.  In it, a visitor from another planet (Jeff Bridges, shown here preparing to utter this line), offers to drive for awhile while his host (Karen Allen) takes a little nap. She sees him blowing through a yellow light and thinks he doesn’t understand terrestrial traffic signals. She starts to explain them to him. “Oh no,” he says. “I remember everything I see.” (Meaning that he has internalized as rules what he has seen her actually do as a driver.) “Green means go. Red means stop. Yellow means go very fast.”
 In 1920, William Potts, a Detroit police officer, developed several automatic traffic light systems, including the first three-color signal, which added a yellow “caution” light.
 And since, in many places, the lights are timed in anticipation of a certain vehicular speed, “getting through” this light means that you have a really good chance of a green light at the next several intersections.
 While it is true that different yellows last for different lengths of time, you do get a sense, when you have driven a route a number of times, what the normal duration of this particular yellow is.
 If we did it in the next 2 years, we could get it done by the 100th anniversary of caution light.
 Why I see unable to forget a line from a forgettable movie I saw once 30 years ago is a question that need not detain us here.