In the world’s major cities, where mobility has become a daily torture, there is a technology that could transform the urban experience without breaking the pavement. These are smart traffic lights: devices capable of adapting in real time to the flow of traffic, reducing traffic jams by more than 35% and prioritizing efficient mobility. However, its implementation faces a barrier that is not in the wires or algorithms, but in the mindset of decision-makers.
“The green light of innovation”
By: Gabriel E. Levy B.
In the 1920s, vehicular chaos began to give its first warning signs. The busiest intersections in cities such as New York or London were transformed into scenarios of tension.
Then, the traffic light became a symbol of order. But that invention, so revolutionary in its time, was not fundamentally modified for almost a century.
Its rigid logic, pre-established cycles, no matter how many vehicles wait or how many pedestrians cross, survived even the irruption of artificial intelligence.
Since the 2000s, however, adaptive traffic control systems began to be developed that read, through sensors or cameras, the real vehicular flow.
Companies such as Siemens, Kapsch or the Israeli NoTraffic offered comprehensive solutions that promised living intersections, capable of responding to the urban pulse.
Already in 2014, a report by the Institute of Transportation Engineers warned that traditional traffic lights generated between 20% and 40% of the time lost in urban travel.
Despite this, many cities continued to bet on outdated models, even as they boasted of advances in mobility.
“The problem is not the lack of technology, but the institutional slowness,” said urban planner Carlos Moreno, creator of the concept of the “15-minute city.”
“Wasted time is money thrown on the asphalt”
While traffic becomes a daily nightmare for millions of citizens, local governments insist on cement solutions: new avenues, highway widenings, depressed crossings, elevated walks.
But evidence shows that these works, while expensive, only temporarily alleviate the problems.
In fact, the theory of “induced demand”, amply explained by the economist Anthony Downs, points out that building more roads ends up generating more traffic, because it encourages the use of the car.
In contrast, smart traffic lights, connected to data networks and equipped with learning algorithms, do not require moving earth or spending on heavy machinery.
Its comparatively economical installation has a direct impact on the flow of traffic.
In cities such as Pittsburgh (USA), which implemented the Surtrac system, waiting times at intersections were reduced by 41%, and travel times by 26%, according to data from Carnegie Mellon University.
Even so, in Latin America and other regions of the world, traffic lights continue to work as they did 50 years ago.
The mobility model is trapped in a logic of infinite expansion, where the car is at the centre of the debate and traffic lights remain as simple lights programmed in loops alien to the reality of the environment.
According to urban planning expert Janette Sadik-Khan, “cities cannot continue to operate with 20th-century infrastructure in 21st-century problems.” Even so, in Bogotá, Mexico City or Buenos Aires, multimillion-dollar investments in urban highways completely overshadow any attempt to modernize the traffic light network.
“A light that thinks: the promise of smart traffic lights”
The principle of smart traffic lights is as simple as it is powerful: adapt the behavior of signaling devices to the actual flow of traffic.
To achieve this, motion sensors, vehicle counting cameras, artificial intelligence and, in some cases, traffic prediction technologies based on historical and real-time data are integrated.
This allows traffic lights not to work with fixed cycles, but to modulate their duration and priority according to the number of vehicles and pedestrians approaching an intersection.
When a street has low influx, the traffic light prioritizes it less; When congestion is detected on another road, it is given more passage time.
All of this happens without human intervention.
The benefits are overwhelming: reduction in polluting gas emissions, lower fuel consumption, improved response times for emergency vehicles, and more equitable mobility.
The case of Hangzhou, in China, is paradigmatic: a coordinated artificial intelligence system was implemented there that managed to reduce travel times by 15% in just six months, according to data published by Alibaba Cloud, the system’s provider.
But beyond the percentages, there is a political dimension that is usually overlooked.
Smart traffic lights imply a decentralization of traffic control: it is no longer an operator who decides the times, but an autonomous, data-driven system.
This has generated resistance in technical bodies accustomed to manual control, and in contractors who see the maintenance of old traffic lights as a safe business.
In addition, cities that implement these technologies require a robust communications network, open data systems, and constant maintenance.
It is not just changing one device for another, but transforming the entire logic of traffic management. And that, precisely, is where many local governments stop.
“Where progress stopped in red: examples that speak”
There are cities that decided to take the leap and are already reaping the rewards.
In Los Angeles, the ATCS (Adaptive Traffic Control System) made it possible to synchronize more than 4,500 traffic lights. According to the Department of Transportation, this contributed to a 12% reduction in travel times on major routes.
In London, the SCOOT (Split Cycle Offset Optimization Technique) system has been operating since the 1990s, but its recent update with artificial intelligence allowed a 13% improvement in traffic efficiency, according to Transport for London.
In Latin America, however, progress is limited. In Medellín, an attempt to modernize the traffic light network ended up bogged down by administrative obstacles.
In Bogotá, only 8% of traffic lights work with adaptive logic, and the rest depend on manual cycles, defined without an empirical basis.
In Buenos Aires, a tender for smart traffic lights was declared void in 2022 due to a lack of qualified bidders.
However, there are glimmers of hope.
In Santiago de Chile, the “Smart Santiago Plan” seeks to integrate adaptive traffic light systems with environmental monitoring. And in Quito, a smart traffic light pilot on 6 de Diciembre Avenue managed to reduce waiting times by 30%, according to the Ministry of Mobility.
But these cases remain the exception. The norm, even today, are cities stopped by brainless traffic lights, trapped in a mechanical choreography that has little to do with current urban dynamics.
In conclusion, while cities invest millions in road projects that barely disguise the structural problems of mobility, the solution could lie in something as simple as rethinking the red light. Smart traffic lights do not promise to eliminate traffic, but they do promise to manage it with logic and efficiency. To ignore them, in the 21st century, is to perpetuate inefficiency with resources that could be better used.
References:
- Downs, Anthony. Still Stuck in Traffic: Coping with Peak-Hour Traffic Congestion. Brookings Institution Press, 2004.
- Moreno, Carlos. The revolution of proximity: from the world city to the city of 15 minutes. 2021.
- Sadik-Khan, Janette. Streetfight: Handbook for an Urban Revolution. Viking, 2016.
- Institute of Transportation Engineers. Traffic Signal Timing Manual, 2014.
- Transport for London. SCOOT Performance Reports, 2022.
Carnegie Mellon University. Surtrac Project Overview, 2020.
