1.1. The Superblock Model as a Response to Health-Related City Challenges
Air pollution is a well-known major risk factor for several diseases and premature death [1
]. Other important health determinants in urban areas are traffic injuries, sedentary behavior, and lack of green areas [2
]. To address these issues, many cities are implementing organizational and infrastructure interventions to encourage residents to walk, cycle, and reduce their reliance on driving [4
]. Examples of these interventions are complete streets programs (streets that are designed and operated to enable safe access for citizens of all ages, abilities and modes of transport [5
]), which have been implemented in many cities in the United States among other places. For example, the London Healthy Streets Approach [6
], which aims to improve air quality, reduce congestion, and help make diverse communities greener, healthier and more attractive places to live, work, play and do business. Additionally the New York Sustainable Streets 2009 program [7
], composed of 164 actions committed to sustainable streets in terms of safety, mobility, world-class streets, infrastructure, greening, customer service, and global leadership.
Barcelona is a dense and compact Mediterranean city in Spain that shares many health challenges with other cities, such as high air pollution levels, traffic noise, traffic injuries, lack of green areas, and few relationship spaces [8
]. The city includes a central area called “Eixample”, formed by a grid of orthogonal streets (creating city blocks) surrounded by what used to be former villages annexed to Barcelona. To address the aforementioned health issues, in May 2016, the Barcelona city council approved the measure “Omplim de vida els carrers” (Improving Life on the Streets), to create superblocks across the city.
The superblock is a new model of mobility that restructures the typical urban road network. With their implementation, superblocks provide solutions to the main problems of urban mobility and improve both the availability and quality of the public space for pedestrian traffic [9
]. Superblocks are made up of a grid of basic roads forming a polygon, some 400 m by 400 m, with both interior and exterior components. The interior is closed to motorized vehicles and above ground parking and gives preference to pedestrian traffic. Though the inner streets are generally reserved for pedestrians, they can be used by residential traffic, services, emergency vehicles, and loading/unloading vehicles under special circumstances. The perimeter, or exterior, of superblocks is where motorized traffic circulates, and makes up the basic roads. Superblocks are emerging as an integral solution to the use of public space, uniting urban planning with mobility, and limiting the presence of private vehicles in order to return the public space to the citizen. The importance of the pedestrian is central in the structure of the superblock, such that each grid section has universal accessibility, there is increased safety due to a 10 km/h speed limit, and the habitability and comfort of citizens in public spaces are enhanced [9
]. As a result, the implementation of superblocks significantly improves urban quality while reducing the environmental impacts of vehicles. It also increases the quality of life of residents and visitors, enhances social cohesion, and increases economic activity [9
The “Omplim de vida els carrers” measure aims to improve the habitability of public spaces, progress towards more sustainable mobility, increase and improve urban green, and promote residents’ participation and co-responsibility [8
]. Initially, superblocks consisted of amalgams of 3 × 3 blocks, where motorized vehicles and above-ground parking were reduced and preference was given to pedestrian traffic in public space [9
]. Currently, due to the difficulty of implementing this plan, superblocks are defined more as larger areas, where the function of each street is recognized and strengthened (approximately 1 in 3 streets is pedestrianized with an expected 20% traffic reduction within the superblock [10
]). The superblock process involves creating an action plan through a participatory process, beginning with a small promoting group (representatives of the neighborhood and/or associations with special involvement in the project who act as a link between the technical group and local residents) and ending with the whole neighborhood.
1.3. The Effect of Urban-Renewal Programs on Health
In a previous stage of this project, we created a conceptual framework of the possible effects of superblocks on residents’ health based on a literature review (Figure 2
]. Briefly, the superblock intervention aims to promote changes in: the public space (improving its use by pedestrians); the different types of mobility (increasing pedestrian and bike mobility and reducing private vehicle mobility); the presence of green areas (increasing and improving urban green and biodiversity); and community participation (working together with residents to design, execute and evaluate the superblocks). These changes are likely to have effects at the neighborhood level, such as a reduction in air and noise pollution and an increase in traffic safety, cycling, and walkability. The increase in the presence of recreational spaces, together with residents’ participation in the whole process, will likely create a higher sense of community and improve social networks while the presence of more people and less cars in the streets will improve the perception of safety. Pedestrian streets also favor commerce and relationships between people in the public space. In addition, some individual-level effects are improvements in active transport and physical activity and social support. However, such improvements can make the neighborhood more attractive, where housing and living affordability can be negatively affected and produce additional effects such as gentrification and displacement. Most of the aforementioned effects can cause effects in health and health inequalities, including improvements in traffic injuries, a reduction in cardiovascular and respiratory diseases, depression, and anxiety, and an enhancement in social well-being. Following this conceptual framework, we discuss the objectives of the project.