this post was submitted on 30 Dec 2023
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I don't know what book that was or what metrics its using, but my local intersections could easily pass 3x the current number of cars per green light if they accelerated together, and right away.
The number of people who poorly merge and cause traffic shockwaves, how slow cars drive in the fast lane, the accidents caused by human error. Really curious how they came to that 75% number.
I was slightly wrong. From page 237 of Algorithms to Live By, The Computer Science of Human Decisions by Brian Christian and Tom Griffiths, further referencing the paper How Bad is Selfish Routing? by Roughgarden and Tardos, it says that
"...the "selfish routing" approach [of cars] has a price of anarchy that's a mere 4/3. That is, a free-for-all is only 33% worse than perfect top-down coordination."
Anyways, the way they got to that number is mathematical game theory. In this case people will choose the fastest route which happens to not be so bad.
It's also very possible that what they're concluding is significantly abstracted, but I haven't read the source reference to know for sure.
Just the number of people being moved on a bus or light rail for a given amount of space tosses that efficiently number away.
Exactly. The point it was making is that perfect top-down coordination takes a ton of resources for a whole lotta nothing.
That's on the macro level with decision making. I think, coordinated has another advantage on the micro level, the traffic jams will move as one without waiting for information spread from the head, the accidents are less likely to happen and jam even more.
Having said that, I'd still prefer a good and technologically advanced tram network to any amount of cars 🥲