Jun 30, 2011

To Pass or Not to Pass Should Not Be a Question

Life is a balancing act. You don’t want to waste any time driving more slowly than you have to, and so it bothers you when you get stuck behind a slow driver on a single lane road, but you also don’t want your impatience to lead to your death caused by a collision with an oncoming car while you are passing the slower driver. To help with balancing act, the Road Makers and Line Drawers have devised a system of lines that communicates to you when you should be patient and when you should pass. This is awesome. Now instead of having just my eyes to rely on, I have this code of solid and dashed lines that lets me know what’s up. This makes me happy. But what I want to complain about is that I could be happier. This system is missing something.

The solid yellow line tells me, “It’s not safe to pass now,” and the dashed line yellow line tells me, “It is safe to pass now,” but there should be another sort of line that is in between the solid and dashed, like a dotted line, that tells me, “It used to be safe to pass but it’s going to be unsafe again real soon, in about 500 yards, so if you’re passing, then you’d better get back on your own side of the road real soon. And if you’re not passing, then don’t start passing now.” There needs to be something akin to a yellow light—something that says to drivers, “The red light is coming soon, so make a decision now.” There should be a dotted line that says, “The solid line is coming soon.” The dashed line doesn’t say that; it just changes abruptly back to a solid line.

Current Situation

  1. This dashed line tells you that it’s safe to start passing.
  2. This dashed line tells you that it’s safe to start passing, but it’s kind of lying. It’s too late to start passing here.
  3. This solid line tells you that it’s not safe to start passing.


Ideal Situation

  1. This dashed line tells you that it’s safe to start passing.
  2. This dotted line tells you that it’s safe to finish passing here but it’s too late to start passing here.
  3. This solid line tells you that it’s not safe to start passing.


When we cross the street as a pedestrian, this middle state also exists. The white light man tells us, “It’s safe to start walking now,” and the red hand tells us, “It’s not safe to be walking now,” and the blinking red hand tells us that we’re in between. It tells us, “It’s not safe to start walking now but if you’re already in the street, it’s safe to keep walking.” The Traffic People have even added a countdown of the number of seconds to let you know exactly where in the middle stage you are. That’s nice.

So, People Who Draw the Lines, please add a middle state to the dashed and solid lines, a dotted line, that tells me, “It’s okay to be coming back onto your own side of the road here but don’t start passing now because the part where it’s safe to pass will be ending very soon.” Thank you.



  • Aaron says:

    My understanding is that when the lines change it is still safe to complete your pass. Have you found otherwise?

    • That wasn’t my understanding of the dashed line but let’s suppose that my understanding is wrong. That means that I mischaracterized the situation in Section 2 of “The Current Situation” diagram. That last part of the dashed line isn’t lying to us; it’s saying the same thing that it’s always said: “It’s safe to start passing now. (And we realize this means that the line might be solid by the time you finish passing.)” Although there is perhaps nothing wrong with that two-state system, I think that there is still something to be gained by adding a third state.

      Compare it to the analogous situation in crossing the street. We could get by with only two states—the white man that means, “It’s safe to start walking now” and a red hand that means, “It’s not safe to start walking now (but we realize that you might finish walking while the hand is red).” Why add a third state to this system? Adding a third state increases the pedestrian’s awareness of exactly where they are in the process because it lets you know exactly where the end is. In today’s system, we have a white man that means, “It’s safe to start walking now,” a blinking red hand that means, “It’s not safe to start walking now but it is safe to finish walking now,” and a solid red hand that means, “It’s not safe to start walking or finish walking right now. You shouldn’t be in the street.” This third piece of information is helpful and it is missing from today’s lane-passing lines but is marked in my proposed system by the change from dotted line to solid line.

      This third state marks definitively the end of the second state, which is unclear in a system of only two states. In the two-state system, it’s unclear where the second state ends because people walk at different speeds (and pass cars at different speeds) and because it’s not clear what speed the road designers have deemed to be the lowest common denominator for the amount of time that it takes to cross the street or pass a car. In the two-state system, you know that it’s safe to start walking at the last point at which you see the white man but you don’t know when exactly will it be dangerous to be in the street, period—maybe it’s 10 seconds after the white man changes to the red hand, or maybe it’s 20. You don’t know. This is a problem.

      This is why we loved it when they added the countdown of seconds to the blinking red hand state that lets us know exactly when the blinking red hand is going to turn to a solid red hand. When we didn’t have the countdown, if we didn’t see the change from white man to blinking red hand and it was a blinking hand when we arrived, then we wouldn’t know how much longer it was going to blink before it became a solid red hand. Now we that we can see how many seconds of blinking red hand we have left, if we get to the crosswalk when there’s only 5 seconds left of blinking red hand and we want to make a dash for it, we can, and we know that if we’re walking with our great-grandmother, then we should probably wait for the beginning of the next cycle.

      We could use the dotted section of the line to provide this type of information. If the dotted section of the line were always a certain distance, like 500 yards, then we’d know exactly how long we had left to pass a slower car.

  • ivan says:

    In Arizona, there’s the same system of lines on the road, but at the point where the line goes from dashed to solid, on the left hand side of the road, there’s a yellow “No Passing Zone” sign that you can see as you get close. You can’t see the lines on the road clearly enough, but you can usually make out the No Passing sign. And if you can’t, that probably means that the dashes continue for a while. It’s quite handy. I think someone must have realized the problem you’re on about, but fixed it with signs instead of paint. (I wonder which one is cheaper… Signs have a bigger upfront cost, but maintenance is probably way less over time…) Anyway, problem solved: move to Arizona.