Urban congestion is a pressing challenge, driving up emissions and compromising transport efficiency. Advances in big-data collection and processing now enable adaptive traffic signals, offering a promising strategy for congestion mitigation. In our study of China’s 100 most congested cities, big-data empowered adaptive traffic signals reduced peak-hour trip times by 11% and off-peak by 8%, yielding an estimated annual CO₂ reduction of 31.73 million tonnes. Despite an annual implementation cost of US$1.48 billion, societal benefits—including CO₂ reduction, time savings, and fuel efficiency—amount to US$31.82 billion. Widespread adoption will require enhanced data collection and processing systems, underscoring the need for policy and technological development. Our findings highlight the transformative potential of big-data-driven adaptive systems to alleviate congestion and promote urban sustainability. Big-data empowered traffic signal control in China can reduce vehicle trip times, creating potential reduction of 31.73 million tonnes (Mt) of CO2 emissions annually and US$31.8 billion benefits per year.
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.
Like they said, it could lead to more people driving. Not only are they uncertain, is it likely to be by an amount that would be more than the emissions saved?
Let’s look at this from another angle. What do you think we should do? Every government on Earth suddenly decides to destroy every car on the planet within the next few months?
Like I said, cars will continue to exist for a while. It makes no sense to put your hands up and say “well, cars are bad. But if they can’t be eliminated completely then we shouldn’t attempt to reduce vehicle emissions at all”.
This change is a good one. I’ve said it already, but you’re letting perfect be the enemy of good.
It makes no sense to put your hands up and say "well, cars are bad.
Nobody is doing that. We’re saying “cars are bad, let’s put money and effort to alternatives so people use less cars”. Putting effort into squeezing more cars on the roads is literally the opposite of that goal. This change, like many other one-more-line-bro changes might look cool, but will make situation worse, if the change will even happen at all.
Yes, if the induced demand results in similar levels of congestion - which it very often does - there would be more emissions in the end.
And you’re right, cars will exist for the forseeable future. I do not however want the government subsidizing car dependency since it is destructive to the environment and to everyone’s health and safety.
A couple of possibilities to drastically reduce traffic:
turn all multi-lane streets within cities into single-lane streets for cars with exclusive bus and bike lanes to treat all forms of traffic equally
reduce all inner-city speed limits to 30 km/h to reduce car noise, emissions and increase pedestrian safety
traffic lights should prefer public transit, pedestrians and bicyclists instead of cars
stop subsidizing parking spaces for cars with city money and drastically reduce on-street parking as cars take away massive amounts of space
put toll roads onto highways as their cost is massively higher compared to fuel taxes. After all, trains have to pay a costly fee to use train tracks already - why should cars have this privilege?
There’s a lot more I could write here but you get the gist. Making car traffic more efficient does not reduce emissions in the long term in the slightest. Making car traffic less efficient reduces emissions instead because people will not use cars as frequently.
And keep in mind, I’m not talking about Bumfuck Nowhere (population: 725) when mentioning public transit. Cities have insane amounts of car traffic which can be massively reduced with just a couple of decisions. This would make car traffic less efficient as right now it enjoys many privileges over other forms of transportation.
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:
Doesn’t go against my comment at all.
Like they said, it could lead to more people driving. Not only are they uncertain, is it likely to be by an amount that would be more than the emissions saved?
Let’s look at this from another angle. What do you think we should do? Every government on Earth suddenly decides to destroy every car on the planet within the next few months?
Like I said, cars will continue to exist for a while. It makes no sense to put your hands up and say “well, cars are bad. But if they can’t be eliminated completely then we shouldn’t attempt to reduce vehicle emissions at all”.
This change is a good one. I’ve said it already, but you’re letting perfect be the enemy of good.
Nobody is doing that. We’re saying “cars are bad, let’s put money and effort to alternatives so people use less cars”. Putting effort into squeezing more cars on the roads is literally the opposite of that goal. This change, like many other one-more-line-bro changes might look cool, but will make situation worse, if the change will even happen at all.
Yes, if the induced demand results in similar levels of congestion - which it very often does - there would be more emissions in the end.
And you’re right, cars will exist for the forseeable future. I do not however want the government subsidizing car dependency since it is destructive to the environment and to everyone’s health and safety.
A couple of possibilities to drastically reduce traffic:
There’s a lot more I could write here but you get the gist. Making car traffic more efficient does not reduce emissions in the long term in the slightest. Making car traffic less efficient reduces emissions instead because people will not use cars as frequently.
And keep in mind, I’m not talking about Bumfuck Nowhere (population: 725) when mentioning public transit. Cities have insane amounts of car traffic which can be massively reduced with just a couple of decisions. This would make car traffic less efficient as right now it enjoys many privileges over other forms of transportation.