Thermodynamics of Seattle Traffic


On my way into work today, I realized that Seattle traffic is one of those human systems that visibly conform to the second law of thermodynamics… OK, that’s a gross oversimplification, but it’s still amazing to watch people intentionally move from a high energy state to a low one, with no good explanation. 




Example:  On the exit I take to get to work every day, there are two lanes that turn left.  Invariably, there is a line of 20+ cars in one lane, and 1 or 2 in the other.  Why no one else uses the other lane is beyond me.  I might understand better if it was always the same lane, but it often changes. 




Another Example:  If someone is doing 60Mp/h in their lane, in a line of cars, with good spacing, and a spot opens up in another lane (left or right)…Someone will invariably dive into that spot, but not change speeds at all, thus blocking that lane for faster traffic. 




On a related note, if you ever need to calculate the noise from a segment of road you’re planning, the National Physical Laboratory in the UK has the calculations for you here. 

Comments (5)

  1. Raymond Chen says:

    Well if there are two available lanes and everyone is crowded into one of them, then clearly there must be a problem ahead that is forcing people out of the empty lane. Best to stay out of that late, to avoid getting caught in that problem.

    This happens to me with some frequency. I’m driving along, hey there’s a huge line of cars and the other lane is open. I’ll stay in the open lane and… oh, that’s why nobody’s in this lane… and now I’m stuck trying to merge into the busy lane and everybody thinks I’m one of those schmucks who’s always trying to cut in line.

  2. I did consider that possibility. I dismissed it though, since there never is a problem at this ramp. I assume, possibly incorrectly, that most of these other people are commuters as well, and would note after a few times that this situation develops with no real cause, and avoid it.

    In the interest of full disclosure, I should point out that I typically am one of those schmucks.

    I’d also like to point out that I only started being one of those schmucks AFTER I moved here from New Jersey.

  3. Michael Fourre says:

    I disagree. You were a schmuck in New Jersey, too. :)

  4. Scott Allen says:

    Somedays driving to work I fantasize about writing a traffic simulation program. Traffic patterns fascinate me.

    I think it would be interesting to see how much of an advantage one gets by being a schmuck, and how what is the impact of the person who pulls into the left lane and uses cruise control.

    Something I think it would just be fun to model all the different types of drivers I see on the road using a state machine.