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A/B Street: A simulation game to fix Seattle's traffic

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Re: A/B Street: A simulation game to fix Seattle's traffic

#71

Post by throwaheyy »

xxpor wrote: post #51
WalterBright wrote: post #35

Fixing the traffic lights would go a long way towards improving traffic flow in Seattle. How much time do you spend sitting at a red light when there's no cross traffic? How often are you and the 5 cars behind you abruptly stopped to let one cross traffic car through? Lots of traffic lights already have cameras on them. Hook 'em up to an AI and a goal of maximizing throughput.

This sounds simple but it really isn't. First, the vast majority of signals aren't networked, they're on simple timers. And you can't just put them on the internet for hopefully obvious reasons. Second, there's a bit of a butterfly effect. Change one thing and the whole system reacts in sometimes unpredictable ways. Third, you need to account for pedestrians too. There's ADA requirements around how long signals are g…

Not really, all the above points was solved 40+ years ago.

https://en.wikipedia.org/wiki/Sydney_Coordinated_Adaptive_Tr...

Re: A/B Street: A simulation game to fix Seattle's traffic

#72

Post by jschwartzi »

throwaheyy wrote: post #71
xxpor wrote: post #51

Earlier quoted context omitted.

This sounds simple but it really isn't. First, the vast majority of signals aren't networked, they're on simple timers. And you can't just put them on the internet for hopefully obvious reasons. Second, there's a bit of a butterfly effect. Change one thing and the whole system reacts in sometimes unpredictable ways. Third, you need to account for pedestrians too. There's ADA requirements around how long signals are g…

Not really, all the above points was solved 40+ years ago. https://en.wikipedia.org/wiki/Sydney_Coordinated_Adaptive_Tr...

I’m curious if you have any professional experience with this? How well does it accommodate bicyclist and pedestrian traffic flow? In Seattle they’re trying to accommodate these kinds of traffic instead of cars because it’s really expensive to build more streets. And we’ve learned over the past 20 years that optimizing for car traffic means making it less safe and harder to walk or bicycle.

Re: A/B Street: A simulation game to fix Seattle's traffic

#73

Post by throwaheyy »

identity0 wrote: post #70
xxpor wrote: post #51

Earlier quoted context omitted.

This sounds simple but it really isn't. First, the vast majority of signals aren't networked, they're on simple timers. And you can't just put them on the internet for hopefully obvious reasons. Second, there's a bit of a butterfly effect. Change one thing and the whole system reacts in sometimes unpredictable ways. Third, you need to account for pedestrians too. There's ADA requirements around how long signals are g…

That article you posted is just stupid. Yes, maybe now people won't be pressing buttons, but COVID won't be around forever. In a few months/years/whatever the pedestrian button will still be around, people will still press them, and they will still be a valid solution to traffic. The article also says: > These buttons have long been decried and criticized by advocates for walking, anyway. The buttons’ purpose is less…

Yes, I stopped reading when I got to this:

> Typically, a person expects the signal to show walk, then flashing don’t walk, then solid don’t walk. Signals follow a familiar pattern and people embed that pattern in their muscle memory. Adaptive signals, however, can flip from walk to don’t walk to walk again

That simply doesn't happen, adaptive or not.

Re: A/B Street: A simulation game to fix Seattle's traffic

#74

Post by Pfhreak »

Rad! It's a bummer that Amazon employees will have a hard time contributing to this (as Amazon prevents collaborating with anyone on any side projects that are 'games'.) Their offices surround some of the worst traffic in the city, and it'd be interesting to have some of their engineers contributing.

Re: A/B Street: A simulation game to fix Seattle's traffic

#75

Post by shagie »

WalterBright wrote: post #35

Fixing the traffic lights would go a long way towards improving traffic flow in Seattle. How much time do you spend sitting at a red light when there's no cross traffic? How often are you and the 5 cars behind you abruptly stopped to let one cross traffic car through? Lots of traffic lights already have cameras on them. Hook 'em up to an AI and a goal of maximizing throughput.

The paper for this is: On Traffic Light Control of Regular Towns by Elina Mancinelli, Guy Cohen, Stéphane Gaubert, Jean-Pierre Quadrat, Edmundo Rofman

https://www.researchgate.net/publication/281356849_On_Traffi... where you have nice (or almost) nice regular blocks with a constant speed. When you start deviating from this, the math all breaks down.

The ideal case would be to pulse the traffic such that given a certain amount of traffic flow and everyone following the proper speed limit that the time it takes for the traffic pulse to get to the next traffic light is green (and the pulse can continue).

This can be seen when you switch from one traffic light synchronization district to another - and hitting a traffic light.

There's a stretch on my commute where when I follow the speed limit (its 25 in this segment), I can go from one end of the traffic district to the next without ever hitting a red light (about 15 blocks).

The thing is that if the traffic isn't pulsed, then the spot where it changes from one traffic district to the next backs up significantly and causes other backups further down traffic.

Re: A/B Street: A simulation game to fix Seattle's traffic

#76

Post by WalterBright »

xxpor wrote: post #69
WalterBright wrote: post #65

Earlier quoted context omitted.

I'm sure those are not insurmountable obstacles. For example, > First, the vast majority of signals aren't networked, they're on simple timers. Doesn't matter. Even doing the ones that are networked would be a big improvement. > And you can't just put them on the internet for hopefully obvious reasons. But you can put every neighboring building on the internet with their security cameras? It's not like you need hires…

The internet issue is a security one. Imagine what would happen if someone could make lights green in 2 directions. To the first point, the networked lights are already in this mode (it's the reason why they added it in the first place). I can't find the report right now but upgrading all of the signals on 2nd from Denny to Yesler cost something like 30 million bucks. The upgrade in the Mercer project area isn't exac…

> Imagine what would happen if someone could make lights green in 2 directions.

I didn't consider it because the solution is obvious. An interlock that makes it electrically impossible to have 2 greens, like an airlock has a piece of hardware that prevents both doors opening at the same time. I suppose I should also mention the obvious that if the internet connection goes down, or the camera lens gets iced up, etc., it should automatically revert to egg-timer mode.

See https://en.wikipedia.org/wiki/Therac-25

> I can't find the report right now but upgrading all of the signals on 2nd from Denny to Yesler cost something like 30 million bucks.

Somehow the money is always found for internet connected cameras to spy on us.

> The upgrade in the Mercer project area isn't exactly a glowing success:

These are solvable problems. Except point 11, which is ironically complaining about it working successfully at what it was supposed to do.

Re: A/B Street: A simulation game to fix Seattle's traffic

#77

Post by dabreegster »

spyder wrote: post #57
dabreegster wrote: post #2

Hi, author here. Previously posted to HN ( https://news.ycombinator.com/item?id=21763636 ). I just released alpha -- check out this cheesy trailer ( https://www.youtube.com/watch?v=LxPD4n_1-LU ). Happy to answer questions! And if you're serious about running this in your city, the importing process has improved greatly since December, so get in touch.

Reminds me of the Citybound game in (slow :( ) development by basically one guy and also written in Rust: https://aeplay.org/citybound He demoed his actor system with 100 000 cars in the middle of this talk: https://www.youtube.com/watch?v=qr9GTTST_Dk Maybe you guys should team up :) (if not already...)

Citybound looks awesome, but development seems a bit stalled. I've been in touch on r/citybound before, am following the project closely. There's also https://github.com/Uriopass/Scale, which has a really awesome demo running of Paris

Re: A/B Street: A simulation game to fix Seattle's traffic

#78

Post by dabreegster »

Pfhreak wrote: post #74

Rad! It's a bummer that Amazon employees will have a hard time contributing to this (as Amazon prevents collaborating with anyone on any side projects that are 'games'.) Their offices surround some of the worst traffic in the city, and it'd be interesting to have some of their engineers contributing.

What, really? It's also an "urban planning tool," does that help?

Re: A/B Street: A simulation game to fix Seattle's traffic

#79

Post by FeepingCreature »

supertrope wrote: post #47
FeepingCreature wrote: post #41

Earlier quoted context omitted.

That's not a reason to not improve infrastructure anymore than "the more chocolate we produce the more people want to buy chocolate" is a reason not to make chocolate. It just shows you're ludicrously underserving demand.

Efficiency matters. If allocating 100 million currency units to widening a highway from 5 lanes to 6 lanes improves people/hour capacity and quality of life less than other solutions, the other solutions should be chosen. In addition to diminishing returns on the way we’ve always done it, there’s a hard limit of about 2000 cars/hour/lane. Chocolate is not free at the point of use but roads usually are. Without price…

The fact that it induces demand makes it more efficient, not less.

Re: A/B Street: A simulation game to fix Seattle's traffic

#80

Post by lotsofpulp »

supertrope wrote: post #47
FeepingCreature wrote: post #41

Earlier quoted context omitted.

That's not a reason to not improve infrastructure anymore than "the more chocolate we produce the more people want to buy chocolate" is a reason not to make chocolate. It just shows you're ludicrously underserving demand.

Efficiency matters. If allocating 100 million currency units to widening a highway from 5 lanes to 6 lanes improves people/hour capacity and quality of life less than other solutions, the other solutions should be chosen. In addition to diminishing returns on the way we’ve always done it, there’s a hard limit of about 2000 cars/hour/lane. Chocolate is not free at the point of use but roads usually are. Without price…

Hence an easy solution to traffic is increase the cost of driving. Which Seattle already has dynamic tolls which change in price:

https://www.wsdot.wa.gov/Tolling/TollRates.htm

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