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.
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: