5mo ago

A new study found adaptive traffic signals powered by big data reduced peak-hour travel times by 11% in China’s 100 most congested cities – saving 31.73 million tonnes of CO₂ annually.

www.nature.com

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cross-posted from: https://lemmit.online/post/5292633

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The original was posted on /r/science by /u/calliope_kekule on 2025-03-01 05:53:17+00:00.

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5mo ago

A new study found adaptive traffic signals powered by big data reduced peak-hour travel times by 11% in China’s 100 most congested cities – saving 31.73 million tonnes of CO₂ annually.

www.nature.com /articles/s41467-025-56701-4

73 comments

"big data" is not generative AI. They're different things. Just in case anyone read that as "AI fixes things".
- It's weird cause technically adaptive traffic patterns are trained using tools like reinforcement learning, which is technically AI, however it's the broad term AI and not GenAI.
- I mean, this is also an area where neural networks will improve things. Neural networks are excellent for optimizing data with an extremely large amount of input variables, as is the case here. You don't need language models, you don't need to steal all the content on the internet for training. You have analysis tools that will easily validate any solution, so you're not going to deal with mystery hallucinations.
  
  It's not an extremely large amount of data at all, you can get perfect efficiency by having lights act on completely local, real-time, sensor data, as in "how many cars are in which direction". AI is useful to recognise who wants to use the light but that's the end of it. You don't need to predict traffic patters as you don't need them to see what's the state of the streets right now, worse, such predictions are a source of BS. Lots of patterns happen all the time that have no precedence as construction sites shift, sportsball games get cancelled or not, whatnot.
- It's a confusing situation, because big data is what it sounds like. Large amounts of data on actual events. But it doesn't mean they didn't use AI to help interpret the data, or to come up with the adaptive traffic signaling.
Why does it often seem like only China is using modern tech to make real quality of life improvements? It's the opposite of the US. Seems like that same modern tech is making everything a bit worse day after day.
- They have more catch-up to do. The US already does things like traffic control, but they have a different goal: they want drivers to feel like they're making progress instead of actually improving things.
  For example, we put traffic signals everywhere instead of teaching people to use traffic circles. Why? Drivers like to drive fast and would rather stop than slow down. Traffic circles improve flow, but they do reduce average speed, whereas traffic lights decrease flow and increase average speed. It's stupid, but we're entitled jerks who like to show off at signals.
  
  but they have a different goal: they want drivers to feel like they're making progress instead of actually improving things.
  Sorry but I want a source for that claim.
- More and more countries are using mass surveillance to control the population so China might not be the only ones using it to deal with traffic at all.
- Take a look at the USA government right now. 😜
  But ya you're right, anyone could have been doing this for a long time. I guess it's just politics.
  
  You wanna reduce traffic times with these better lights? Think of all the billions of dollars lost to advertisers since people won't be forced to look at their ads now while waiting!
It's infuriating when a light turns red while only a few of the cars have gone though, makes sense a more intelligent algorithm would be more efficient.
- I pass like 15 lights on my commute and the amount of time standing still for NO REASON is absolutely infuriating. How much could it possibly cost to add a simple sensor? No cars coming from the sides? Light stays green! But no, it's all just dumb timers instead...
  
  Interestingly, some lights are set up to deliberately slow down speeders. If you are above the speed limit, they turn red, just to slow things back down. Unfortunately, most of the people involved never put cause and effect together.
- I think it's often the opposite, a traffic circle is much less intelligent but quite effective at increasing traffic flow. We can't put them everywhere, but we should put them in more places.
They will truly do anything not to admit the problem is cars
- No they aren't. They're saying smarter traffic systems are an improvement over what we have now. I've looked in the article and nowhere do they say cars aren't a problem, or that emissions is down to traffic lights not cars.
  I see so many examples on here and on Reddit of people letting perfect be the enemy of good.
  Whether we like it or not, cars will be around for a while. It makes no sense to put zero effort into improving efficiency in the meantime. You don't have to be so all-or-nothing.
  
  Yes, and such intelligent systems can also optimize for pedestrian traffic, reducing the time waiting for a walk light, monitor bike lane usage, track dangerous intersections, improve emergency response times, prioritize buses and trams, etc. It's good for people to be gathering this data and trying to make things better.
  
  And next year the congestion will be the same as before, except with even more cars and even more emissions.
  This is equivalent to building another lane on a highway to increase throughput and decrease traffic jams. In the beginning, emissions will be reduced since traffic jams occur less frequently. And then, through induced demand, there's congestion again.
  Improving car throughput directly leads to increased emissions with a small delay.
  From the paper:
  Increased speeds from adaptive signals may induce additional travel, as people opt to drive more or travel farther, potentially offsetting some congestion benefits. Our models do not fully capture induced demand due to data limitations, but adaptive signaling generally supports higher traffic volumes and smoother flows.
- Exactly all this does is create more road capacity which will inevitably lead to more cars and then increased congestion.
  This is the big data equivalent of “one more lane”.
- China has more public transit of every type than the rest of the world combined at this point, and most of their cities are quite pedestrian centric.
  Cars are a luxury outside the rural areas, and they're a problem, but this is unrelated to that.
- It‘s even worse. You need mass surveillance and strip away human rights to do it the way China does it. And I am sorry, but that‘s not worth it. There are countless better ways to deal with climate change because in the end of the day it‘s still a self serving mission for the most part.
  
  Which human right does this strip away?
  
  Your take is that changing traffic management is a violation of human rights?
Wait until it learns that lanes can be turned into dedicated tram corridors.
- Wait until they run the numbers on carbon emissions of stop signs vs. sensible yielding laws.
  
  Yup. Most European countries barely use stop signs as opposed to the US.
Maybe they could just try a roundabout? Or even better... Ditching the dead end of car dependency for free public transport?
Because phony "AI" is here to save capital, not the planet.
- The article mentions specific deterministic algorithms so I don’t think it’s AI in the way youre thinking.
- Honestly I've seen round abouts in the US and while I totally think their more efficient and causes less wrecks statistically. People are fucking idiots. Everyone complains and thinks their worse and hate them to hell and back. No amount of facts or convincing will change their minds. It's insanity. People are so resistant to change it'd incredible the mountain out if a mole hill they will make it out to be.
  
  It doesn't help that we use them poorly. We have one between a stoplight and a shopping area, and it always gets backed up. They're never in high traffic areas, so drivers never get used to them. I want to replace highway intersections with traffic circles instead of putting them in random neighborhoods.
In Switzerland we have sensors in the streets at most crossings. And behind it I assume, is a determinate algorithm whoch decides who has green for how long. This mainly is done to avoid the backing up of one crossing into another.
In my little Southern US town the lights seems to work logically and traffic flows nicely, noticeably so. I'm never sitting at a light screaming, "Oh FFS turn!" or "Why did that light change and there are no cars?!"
Traffic only gets a bit thick on the main road in late afternoons. Not much to be done there, it's a major east-west thoroughfare connecting several towns.
Have no idea how they're doing this. Sensors I'm guessing? Seems like we're too poor for fancy civil engineering like that and I'm sure we can't afford what the article talks about.
Anyone know how that might work?
- Sensors are cheap and have been around for a long time, but I'm going to guess the number one reason is the small part. Fewer cars = less traffic.
  I've actually watched a city I visit regularly grow over about 20 years and it went from them having zero traffic to Los Angeles style traffic jams. This is despite their best efforts like making extra wide roads, using roundabouts, etc.
- Look for a square or an X (or a square with an X in it) right Infront of the stop line for the lights. If it's there, that detects a car waiting.
  There may be more of them further up the road to detect more cars waiting/arriving.
  They are basically using big loops of wire to detect cars through magmatism.
  They tend not to detect cyclists, so I often have to move to the side and wave cars forward so lights on side streets will change.
- Sensors on a main road and well set timers after a few months of data can do wonders and be extremely low cost, but it requires some upfront spending and enough public will to put up with bad traffic until everything is tuned.
See, this is a reasonable use of horrible dystopian technology.
It doesn't excuse the rest of it, though.
- What's horrible about traffic signal optimization algorithms? This isn't GenAI, just an algorithm that looks at traffic patterns and optimizes signals to improve flow. There's nothing dystopian about that.
  
  The horrible and dystopian part for the comment above yours is the fact that it happens in China, which is ontologically bad and oppressive
Oh so I don‘t have to worry about China‘s increasing emissions output because they use unhinged mass surveillance and terror against the people to put a band-aid on it. Cool…
- Doesn't China emit like half the amount of carbon per capita compared to the US?
  
  China has a very large capita.
  
  Yes, and they are by far the best in green energy
  https://www.carbonbrief.org/analysis-record-surge-of-clean-energy-in-2024-halts-chinas-co2-rise/ And it would be even worse for the US and others if they would produce all the stuff they out now outsource to China.
  It's a typical Chinophobe 'at what cost' commenter.
  There is literally nothing they can do right.
  
  One issue with that is China is still a heavily bike and moped driven country. The issue is when more of their population is able to afford cars. So they could still "catch up".
- I would be happy for sensors at traffic lights that detect whether cars are there or not. I don't consider that to be meaningful surveillance.
  
  But they already have sensors. That‘s not what China differentiates from the rest here.
- Of course there has to be a sore loser China bad commenter with some made up BS
  
  I am used to tankies on Lemmy but man, if you say China isn‘t an Orwellian surveillance state you‘re just lying through your teeth.

73 comments