The implementation of green axes and the reduction of motorised traffic in cities is effectively consolidating itself as a strategy to significantly lower environmental noise levels. A study conducted in the city of Barcelona shows that, one year after pedestrianising several streets, the average daily sound level decreased by 3.1 decibels (dB).
The research, led by the Institut de Ciència i Tecnologia Ambientals of the Universitat Autònoma de Barcelona (ICTA-UAB) and recently published in the scientific journal Cities & Health, compares data from seven permanent acoustic monitoring stations before (2022) and after (2023) the pedestrianisation of the new green axes in the Eixample district, in the city centre. These interventions are part of the “superblocks” (superilles) programme promoted by the city in recent years. It is one of the few empirical evaluations based on continuous sensors analysing the impact of pedestrianisation on urban noise at street level.
The results indicate that noise reductions are more pronounced during daytime than at night, and greater on weekdays than on weekends. The most substantial decreases were recorded in newly created public squares located at the intersection of two green axes, areas that are particularly distant from through traffic.
The study also identifies a qualitative shift in the soundscape of these streets. Although the overall reduction in noise is widespread, data show that weekend afternoons and evenings are an exception: during these periods, sound levels are similar to those recorded before pedestrianisation. This pattern suggests that noise associated with recreational human activity and outdoor leisure is occupying the acoustic space previously dominated by motorised traffic, especially at times of peak pedestrian activity.
Despite these improvements, post-intervention noise levels still exceed the values recommended by the World Health Organization (WHO) and the European Union (EU), which place recommended outdoor noise thresholds at around 53–55 dB. Previous studies have estimated that 94.7% of Barcelona’s population is exposed to noise levels above these guidelines, highlighting the difficulty of meeting international standards in densely populated Mediterranean cities.
According to Samuel Nello-Deakin, researcher at ICTA-UAB and lead author of the study, the findings “indicate that concerns about pedestrian and outdoor leisure noise exceeding traffic noise are unfounded,” at least in the locations analysed.
The study combines this acoustic sensor data with a survey of 1,211 residents of the Eixample district, allowing researchers to examine how noise affects everyday domestic life. The results show that 59% of residents living on main traffic-heavy streets report that noise affects the use of street-facing rooms, compared with 47% of residents living on the new green axes.
Reduced noise levels are also reflected in the use of private outdoor spaces: residents of traffic-calmed streets—including the new green axes—use their balconies more frequently than those living on streets with heavy traffic. This shift suggests that lower noise levels contribute to a more comfortable and intensive use of housing.
Overall, the study provides robust evidence that traffic calming can reduce urban noise without leading to an equivalent increase in noise from pedestrian activity. The authors note that these findings are relevant for other dense cities seeking to improve urban quality of life through pedestrianisation and traffic reduction strategies.