The familiar frustration of waiting at a red light on an empty street could soon be a thing of the past in Barcelona. The City Council has announced an ambitious plan to integrate artificial intelligence into its traffic light network, aiming to create a more fluid and efficient urban transport system that adapts to traffic in real time.
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A simulation at the busy Eixample intersection of Carrer d’Aragó and Carrer d’Aribau has already shown promising results. The Universitat Politècnica de Catalunya (UPC) conducted this study, finding that an AI-driven system could reduce travel times for all road users – including cars, buses, bicycles, and pedestrians – by an average of 9.5%.
This initiative represents a significant leap towards a fully adaptive traffic control system. Currently, most city traffic signals operate on predetermined sequences, changing by time of day or week. However, they cannot react to unexpected congestion or clear roads. The goal is to replace this rigid system with one that uses AI to analyse live traffic data and modify signal timings on the fly.
From Theory to Trial
To turn this vision into reality, the City Council and Fira de Barcelona are launching an innovation challenge through the Barcelona Innova Lab Mobility programme. The city is inviting technology companies to propose solutions for this complex urban puzzle.
Two winning projects are due to be announced during the Smart City Expo World Congress this autumn. Each will receive up to €100,000 to implement their technology in a four-month pilot programme scheduled for 2027. According to La Vanguardia, potential pilot locations include high-traffic corridors like Carrer de Sants, Plaça Alfonso Comín, or the entry and exit points of Avinguda Meridiana.
This is not the first time the city has turned to AI to solve mobility issues. Transports Metropolitans de Barcelona (TMB) recently trialled AI to detect vehicles illegally occupying bus lanes and is testing cameras at bus stops to better align service with demand. These initiatives mirror a wider regional trend towards using smart technology in urban management, such as the plan in nearby Badalona to deploy AI and 600 new surveillance cameras to enhance public safety.
A Question of Priorities
While the prospect of shorter journeys is appealing, city officials are clear that the primary objective is not simply to speed up car traffic. Deputy Mayor Laia Bonet stated that the goal is to “prioritise public transport, pedestrians, and sustainable mobility.”
“If the light is green for longer for some, it means others will have it on red,” Bonet acknowledged, highlighting the delicate balancing act required.
The preliminary UPC analysis underscored this challenge. In the simulation at Aragó and Aribau, those travelling along Aragó benefited most, while those on Aribau experienced slightly longer waits. This trade-off will be a central consideration as the project moves forward. It also aligns with the city’s broader strategy of reclaiming street space for pedestrians and cyclists, visible in the new Diagonal bike lane and the ongoing overhaul of major thoroughfares like La Rambla, which has already created significant traffic diversions.
A Global Pioneer?
Other major cities, including Paris, Shanghai, and Singapore, already use dynamic systems to coordinate traffic lights. However, these systems generally rely on a library of predefined plans activated by specific conditions. Barcelona’s ambition, however, goes a step further. It plans to use AI to create and modify traffic light phases in real time, a more advanced and flexible approach not yet widely implemented.
The path to a fully AI-managed traffic grid is long and will require substantial investment to modernise thousands of traffic control units across the city. The tightly interconnected street grid of the Eixample district presents a particular challenge, as a single timing change can have a ripple effect across numerous blocks. Every adjustment will require meticulous study before rollout.
For now, the upcoming pilot project represents a crucial first step. If successful, it could pave the way for a revolutionary change in how Barcelona’s residents and visitors navigate the city, making journeys smoother, greener, and more efficient for everyone.
