Urbanization in Mexico during the XX Century intensified from an urban population of 10.6% of the total population in 1900 to 20.1% in 1940, 51.8% in 1980, and 62.5% in 2010 (Sobrino, 2012). During the same period, the national population grew from 13.6 million to 112 million inhabitants. The growth of the urban built environment has followed the same upward trend, notably since the advancement of the neoliberal urbanization model that has promoted urban sprawl and, consequently, the expansion of the urban built environment (Rossi and Vanolo, 2012). According to the European Commission’s Global Human Settlement project, the urbanized space in Mexico increased from 3,591.35 km² in 1975 to 5,664 km² in 1990, 8,219 km² in 2000, and 10,794 km² in 2015 (GHSL, 2020). If this trend indeed continued at the same rate as in the last 10 years, by 2023 the urbanized space probably reached 12,110 km². Contrary to that tendency, compact cities with mixed land uses have demonstrated to be more resource-efficient because their “metabolic profile,” that is, their consumption of energy, materials and thus land, tends to be lower than that of their sprawling counterparts (UNEP, 2021). Additionally, compact cities have been associated with a diversity of health benefits, including lower levels of obesity and diabetes (Stevenson et al., 2016; Howell and Booth, 2022; WHO, 2022; Strain et al., 2024).

Therefore, to confront such challenges governments are increasingly focusing not only on implementing ecotechnologies and adopting sustainable, circular and inclusive practices, but also on urban form management to promote land use planning and zoning processes that may encourage mixed land uses and medium densities. Such effort is also accompanied by the creation of synergies between different public transport systems to promote intermodal passenger transport, leading to what has been termed as “strategic [urban] intensification” (UNEP, 2021).

Transit-Oriented Development (TOD) model has emerged, particularly in the past couple of decades, as one of the main mechanisms to counter automobile dependence, prevent urban sprawl, reduce traffic congestion, and improve access to public transport and walkability. This approach has been recently coupled with the above-mentioned notion of strategic intensification, understood as the process of “…intensifying the number of jobs/people/services located within a network of primary and secondary high-density nodes that are well connected by efficient and affordable public transport systems” (UNEP, 2021). The orientation of land uses has thus been part of the TOD models, which also include measures for zoning, the strategic placement of urban amenities, the delineation of walkable districts, the development of vacant intraurban spaces, the establishment of urban reserves and desirable density levels, and even limits or boundaries to the expansion of urbanized space (Ibid.).

Although there are numerous cases of TOD implementation in countries of the Global North and South, such as Amsterdam (Pojani and Stead, 2018), Stockholm (Paulsson, 2020), Curitiba (Lindau et al., 2010), or Mexico (Guerra, 2014), recent research has demonstrated the existence of externalities associated with this model, especially in Latin American cities (being among these gentrification and the exacerbation of social inequality; Knowles et al., 2020; Bokhari and Farahnaz, 2022).

Considering the above, this paper, situated within urban form studies, focuses on two underexplored issues within the Global South literature: (1) designing intervention scenarios that could help counteract or mitigate the externalities generated by TOD models in Global South cities; and (2) operationalizing the fine-grained urban form elements inherent to the interface between public and private spaces that are contained in the micro-scale urban morphology layer of typomorphological and Kropf’s scale hierarchy analyses (Kropf, 2017). These elements include street, block, plot, buildings, rooms, structure, and materials which are typically not incorporated into TOD models (Mobaraki and Vehbi, 2022). We consider that, being part of the micro-scale, such aspects are crucial —including as well the design criteria for responsive environments, urban image, and sense of place. In fact, some theories (Jacobs, 1961; Lynch, 1959; Bentley et al., 1985; Augé, 1993) and empirical studies (Liu et al., 2020; Ortega et al., 2021; Peimani and Kamalipour, 2022; Mobaraki and Vehbi, 2022) argue that such notions can increase the potential of public space by creating safe, meaningful, and more sustainable traveling routes.

The objective of this work is to develop and test an analytical and assessing tool of the urban form on a micro-scale that may support the processes of urban territory development, especially in terms of active mobility and the integration of those aspects that primarily influence people’s behavior and their choice of modal distribution. We start with a theoretical framework centered around the notions of urban vitality, urban image, and active mobility, all key aspects of the previously described notion of sustainable strategic intensification which, particularly for the Global South, must be conscientiously inclusive and increasingly equitable to close the existing gaps in the coverage and intermodality of quality public transport, including provisions for active mobility.

Our analytical and assessing tool materializes in a “Sustainable Urban Form Index” (SUFi), whose themes and indicators are derived from the theoretical postulates of sustainable urban design, urban psychology, and urban sociology. This Index, which aims to understand the transformation potential of proximity areas, is applied to two case studies within TOD zones in the city of Monterrey (Mexico). These case studies represent the consolidation of dispersed metropolitan urban patterns at the expense of compact ones (Dadashpoor and Malekzadeh, 2020), which emerged during two historical politic-economic cycles: the “Mexican miracle” associated to State-led development and the neoliberal, market-driven era. These cases provide an initial approach to identify sustainable urban transformation alternatives for Mexico’s contemporary urban built environment. Various studies on urban form have been developed mainly from the exact sciences, geography, architecture and philosophy, contributing knowledge from historical-geographical, typomorphological, spatial analysis, and urban image approaches (Conzen, 2009; Hillier, 2009; Meenar et al., 2019). In general, within this literature there is consensus about the potential of transport infrastructures and land use management to modify daily mobility practices (Newman and Kenworthy, 1999; UNEP, 2021). The relationship between urban form (UF) and daily mobility (DM) has become fundamental in all spheres, predominantly due to the paradigm shift in accessibility adopted in recent decades based on the understanding of the triad distance, time, and speed (Banister, 2011).

While developed countries have sought to reduce the carbon footprint of their mobility practices by, for example, increasing pedestrian and cycling paths, these solutions have not had the same traction in many Latin American cities. Particularly in those experiencing recent and rapid expansion, which often lack robust and sustained territorial planning, there is a tendency to encourage the use of private automobiles. It is worth noting that beyond the relationship between urban form and daily mobility, urban form incisively affects the efficient use of resources (including land) (UNEP, 2021) and consequently, urban sustainability. Additionally, it has implications for urban vulnerability and resilience in the face of increasingly and socio-spatially differentiated impacts of climate change (IPCC, 2023).

Although the concept of sustainable urban form (SUF) is still under construction, the most used approaches promote the compact and polycentric city model, which aims to avoid accelerated expansive growth. For Milder (2011), for example, sustainable urban form consists of five key elements: density, surface, land uses, roads and public transport infrastructure, and economic relations with surrounding spaces.

Hillier (2009), in accounting for the concept of spatial sustainability, highlights the need to move towards much clearer definitions to make concrete and forceful impacts, for example, through studies focused on the geometry of urban planning (rather than general regional studies, which, while useful, remain relatively distant from the necessary actions for urban space transformation). Meanwhile, Higueras (2007) states that urban bioclimatic analysis of the four major global climatic regions is part of the desirable route for public space design (regulatory layout, street width, building height, type of vegetation, among others) based on the climatic factors and elements of each latitude, reaffirming the need for micro-scale studies.

The relationship between urban morphology and sustainable urban form has been well identified and discussed in recent studies. The model developed by Mobaraki and Vehbi (2022) demonstrates a significant interaction between each element of urban form with the typomorphological approach, using scale hierarchy as a mode of variable compatibility in the different morphological layers from the regional, city, block, and building scale. Meanwhile, Peimani and Kamalipour (2022), through mapping the spaces surrounding transit stations, explain the interaction between key morphological elements and access networks, concluding that forms of urbanity and informality are integral to the functioning and transformation of public space. This contributes to complementing TOD policies by addressing the fine-grained characteristics of public space.

Additionally, Banister’s (2011) analysis demonstrates the hegemony of a conventional transportation paradigm strongly linked to the idea that travel time should be reduced by increasing circulation speeds, which has been the basis for deconstructing dominant narratives, positioning the reduction of travel distances as a priority.

Promoting cities designed or redesigned at a human scale, where residents of all ages, origins, and abilities can access their daily needs—housing, work, food, health, education, culture, or recreation— within a 15-min walk or bike ride, has been at the center of urban policy in various French cities, starting with Paris (Moreno et al., 2021). Similarly, the role of subcenters in reducing motorized trips in Berlin supports the hypothesis of the 15-min city (Wagner et al., 2022). The effects of density (Montejano, 2017), diversity, land use, and neighborhood type on mobility have also been identified (Stojanovski, 2019), as well as differences in mobility relative to income in various urban densities in the USA and Great Britain (Giuliano and Narayan, 2003).

Wang et al. (2022) point out that although TOD models increase the intensity of public transport use and promote subjective well-being, in the Global South this model behaves similarly to the Global North, inducing gentrification and social inequality. This highlights the need to review the model and its relationship with attractive, comfortable, safe and accessible public spaces (Ortega et al., 2021) to enhance inclusive active mobility.

In urban form studies the urban block is recognized as the smallest scale unit within the microscale and, as such, it constitutes the basic building block of the urban fabric. Beyond this, the literature identifies other scales such as the housing complex, the popular neighborhood, and, in Mexico, the Basic Geostatistical Area (AGEB), the latter serving as a unit scale for managing population and socioeconomic information and data. In the Mexican context, the first microscale contains two typologies: typical blocks and building blocks. Typical blocks, which predominate in Mexican cities, are designed public infrastructure such as street lighting, drainage, and sidewalks. In contrast, building blocks, associated with housing complexes, are defined not by streets boundaries but by common areas such as hallways, green areas or parking lots, and represent a minority within the urban fabric (INEGI, 2020a, 2020b). Furthermore, a proximity scale is defined, delineated by elements of its form, such as roads, railways, or administrative boundaries. These areas may or may not align with the neighborhood scale but are functionally defined by active mobility dynamics within their limits. These micro-scale typologies exhibit particular characteristics, including socio-spatial segregation –exacerbated by the enclosed forms adopted by housing complexes in recent decades–, the presence of informal commerce, which contributes to traffic obstruction and perceptions of insecurity, and the fragmentation of land uses, which promotes spatial dispersion and hampers proximity to basic services.

Based on a search for the most cited academic articles on urban form and sustainable mobility, some characteristics and approaches have been identified, as well as knowledge gaps and the usefulness of existing studies in a Latin American context. For this, the Web of Science and Scopus databases have been used, considering “urban form” and “sustainable daily mobility” as search terms, limiting the search to open-access articles from 2000 to 2022. From the results obtained, 26 papers emerged as the most cited. These papers were subsequently examined and classified based on scale, type of mobility, context, and dimensions or variables of analysis; see Figure 1.

Our findings reveal that knowledge production on the subject has favored meso- and macro-scales (Aslam et al., 2019; Bai et al., 2021; De Vos and Witlox, 2013; Degen and Rose, 2012) with 96% of the approaches at the metropolitan and municipal scales compared to 4% of them at the neighborhood or proximity scale (see Figure 1A). Regarding the type of mobility, the analyzed literature (Eggimann et al., 2021; Ewing et al., 2018, Hickman et al., 2013; Hidayati et al., 2021; Kandt, 2018, Klinger et al., 2013) focuses on passive mobility (61.5%) and active (Hino et al., 2019; Lan et al., 2017, Mateu et al., 2017) modes (38.5%), while only 4% on non-performed trips, (Mouratidis and Papagiannakis, 2021) or non-mobility (Figure 1B). Regarding case studies, most are made up of European (Ogilvie et al., 2008), Asian, and American (Muñiz and Domínguez, 2020) cities, representing 54, 23, and 15%, respectively, compared to 8% of studies (Muñiz et al., 2016) for Latin American cities (Figure 1C). The analyzed variables or dimensions show more balanced percentages, with 46% of the papers dealing with socioeconomic aspects, 46% with ecological issues (Vich et al., 2019; Xue et al., 2011), 73% with cultural characteristics (Shaheen et al., 2019; Stojanovski, 2018), and 38% with normative and design aspects (Tiitu et al., 2020) (Figure 1D).

This research presents a case study perspective aimed at providing insights from the Global South to foster a more inclusive and equitable debate on urban form design in relation to sustainable daily mobility. In this regard, the lessons learned could be useful for other cities in the same region that share similar characteristics and developmental processes. While the term “Global South” refers to countries that, regardless of their geographic location, share similar social, economic, and political conditions, including limited capacities and structural challenges to address social inequalities, the city of Monterrey behaves in some ways differently. From a cultural perspective, perhaps due to its proximity to the United States, Monterrey has more strongly embraced than other Mexican cities the idea of well-being associated with suburban housing, with the automobile as the ideal form of mobility. At the territorial level, Monterrey presents an urban development rate that surpasses that of Mexico City and Guadalajara. Its population is characterized by relatively high purchasing power and low levels of marginalization, all factors that contribute to a favorable profile in terms of economic inequality when compared with the rest of the country. Furthermore, over the last 20 years, this city has shown a sustained increase in both its vehicle fleet and GHG and particulate emissions. These aspects position the region as an area of substantial economic potential but also of significant environmental impacts where there are also significant socioeconomic contrasts and marked socio-spatial differentiation. Consequently, Monterrey and its mobility patterns represent an atypical combination of features, making it especially challenging and requiring more in-depth knowledge and understanding.

A “critical case” can be defined as one of strategic importance in relation to the overall problem (Flyvbjerg, 2006). To assess how micro-scale urban form influences sustainable mobility, it is useful to select two contrasting typological cases studies that have, in general terms, been replicated in other Mexican cities as well as in cities in other countries of the Global South. In this study, the critical cases consist, on one hand, of a residential area whose surroundings largely support active mobility, and on the other, an area that meets these conditions to a lesser extent. Therefore, if SUFi yields certain results in these two cases, such findings may also shed light on mobility patterns in other urban contexts with similar typologies.

As already mentioned, there were two major periods in the urbanization of modern Mexico: the Mexican miracle (1940–1970), so named for the unprecedented magnitude of economic progress, driven by the state as the main driver; and the neoliberal era (1982–2018), linked to market strategies seeking to rescue the country from the crisis following the decline of the import substitution model in the 1980s. Following import substitution, the accelerated rural–urban migration led to a housing crisis (Miranda, 2014), which was addressed by State institutions empowered to mass-produce housing. The projects created for this purpose adopted the criteria that were hegemonic on a global scale at the time, specifically those emanating from the so-called International Modern Architecture Movement (Sánchez, 2012).

Although this movement proposed the separation of land uses into vertical housing blocks, its incursion into social housing projects in Mexico did not occur as such. Instead, it opted to promote building density while incorporating a mix of other land uses, such as commercial, educational, and recreational. This currently represents areas that, due to their population density, are more viable for the installation of public transport lines and active mobility. In Monterrey, this housing boom began around 1960, at a time when other residential buildings with these characteristics did not yet exist, as the suburban housing culture predominated, with townhouses offering a quiet, safe place with a family atmosphere. It could be said that this region of the country was influenced from that moment on by both cultures, but with greater emphasis on the latter, thus generating expansive and unsustainable urban development, which has been accompanied by high-speed urban highways.

On the other hand, starting in 1982, policies such as the elimination of public housing subsidies, housing deregulation, and the reduction of the state’s regulatory role allowed a major involvement of the private sector. Constitutional amendments enabled the privatization of communal lands, making them available to the real estate market as low-cost development sites. This deregulation led to various unsustainability challenges due to factors such as the inefficient use of urban land and resources. As a result, housing developments far from urban centers became the norm, creating a reliance on private vehicles due to limited access and deficient public transport service available, which primarily served inner-city residents.

Monterrey, viewed as the quintessential Mexican industrial capital, has been associated with an image of an aggressive, dirty, and polluted city (Prieto, 2014). It has also historically stood out for its ideology of “progress” associated with the development of modern urbanism and architecture. According to Prieto (2014), various political changes in this region around 1914 laid the foundation for a shift in the appreciation of the most emblematic buildings inherited from a colonial past (such as churches and commercial buildings). This limited interest in valuing architectural heritage also implied a social ideology of modernity, which later contributed to the deterioration of residential complexes such as Condominios Constitución, in favor of the rise of developments located on the outskirts like La Alianza. This can be interpreted as one of the reasons for the limited success of the so-called modern movement in this city.

Monterrey’s urbanization process has been characterized by a clear separation of land uses (single use) and low density, the latter especially reinforced by low-density residential development (by 2015, 96% of housing was single-family and 2% was vertical housing; INEGI, 2015). This expansion has resulted in Structured Public Transport (TPE) being accessible just by 14% of homes, while only 11% of them have proximity to workplaces. The polygons analyzed – see further details below – correspond to two different areas of the city: the center and the periphery of Monterrey.

The Monterrey metro system, which began operating in 1991, has 3 lines that influence four of the 14 municipalities in its Metropolitan Area. Bus units generally travel alongside cars, often exceeding their maximum capacities, leading to delays and limitations in service, safety, and user satisfaction. By 2014, the first bus rapid transit (BRT) line was inaugurated, complementing the services of the aforementioned system. The distribution of public transport within the urban area has been and remains unequal, leaving most of it without access. This situation has been addressed through densification in areas adjacent to public transport but has not yet resulted in significant transformations.

In terms of urban sustainability, Monterrey’s urban quality conditions can be understood through a futuristic-stridentist imaginary (Prieto, 2014), which rejects the idea of a historical city, including the modern movement era. Instead, characteristics like speed and grandeur manifest a sort of modern city heavily dependent on automobiles, suburban housing, and intense material and energy consumption, with 4.2% of the national population, the metropolitan area of Monterrey accounted for 5.1% of the total urban demand for resources in 2022 (Delgado et al., 2023). At the level of urbanity, factors like walkability, microclimate, or urban image become less important compared to historical cores or city centers, which will gradually lose their role as social spaces, shifting towards consumption-mediated spaces like shopping centers under neoliberal urbanism influences.

In 1964, the construction of the Condominios Constitución residential complex on a site adjacent to the historic center marked the beginning of the modern era with a strong aesthetic language influenced by European functionalist roots. This urban development features resource-efficient characteristics such as compactness, density, and microclimate design. The “Condominios Constitución” proximity polygon consists of 51 regularly plotted blocks oriented north–south and east–west, covering an area of 9.52 ha. In contrast, the “La Alianza” case comprises 24 irregularly plotted blocks with various orientations. Using data from Google Earth, INEGI (2020a, 2020b), and thresholds established by specialized literature, the necessary cartography was developed to estimate 34 urban form indicators (see Table 1).

The results of the SUFi application in Condominios Constitución show an overall score of 59.80% potential for active mobility (Figure 8), indicating positive outcomes with significant areas for improvements, especially in personalization and resilience indicators, followed by polyvalence, accessibility, and legible image indicators, where certain criteria are met but others are lacking.

For “La Alianza,” the results reveal a 24.21% potential for active mobility, positioning them negatively, as only 6 of the 34 indicators scored well, with compactness, multisensory experience, polyvalence, personalization, and resilience scoring zero. In contrast, the urban form design of “Condominios Constitución” shows higher potential for active mobility, meeting acceptable levels of compactness, proximity, and density, as well as elements that offer a legible image and good accessibility management.

The presented index offers a particularly necessary perspective in the study of urban form and morphology. At the micro-scale of proximity, it is possible to incorporate fine-grained urban design aspects related to the interface between architecture and public space, which have so far been largely overlooked in current urban design regulations, as they are often regarded as theoretical without binding power for practical application. The concepts of urban vitality, urban image, and urban resilience effectively operationalizes the necessary criteria to address both the externalities generated by TOD models in Latin America and the need for creating walkable, sustainable, and resilient spaces in a broad sense. This understanding stems from the fact that walking, beyond merely covering the distance between two points, is a social act that depends on the identity, sense of place, and sense of belonging fostered by architectural and urban design.

According to Koolhaas (2006), contemporary cities face a lack of identity. The accelerated pace of urban population growth has created a disconnect between function, form, meaning, prioritizing the first two with the support of the rise of the motorized city, which inherently fosters and entrenches unequal urban development. For this reason, instilling public space with significance, with elements that tell the local history to prevent them from becoming empty spaces traversed only out of necessity, is a feasible task if both the material potential—analyzed here—and the imaginaries expressed in social representations are considered.

Creating identity requires gathering and concentrating elements. However, the principles upheld by peripheral urbanization, increasingly manifest since the onset of the neoliberal era, focus more on meeting material or functional needs from an individualistic perspective (which in turn depends on individuals’ purchase-capacity). The idea of meeting a need for shelter is achieved while simultaneously suppressing everything that generates attachment. These areas, like the case study of “La Alianza,” sometimes serve as “dormitory cities” or “sacrifice zones” where urban memory is considered not relevant.

Our findings have provided a clear image of the morphological possibilities presented by each topic in the different cases (Figure 8), enabling the modification and management of aspects that could improve their potential for active mobility. In the case of the compact city represented by Condominios Constitución, its characteristics of compactness, density, proximity, and accessibility—related to mixed land uses—make managing the other topics (which have zero scores) more feasible in terms of time and cost, given their short- and medium-term nature. Conversely, for the diffuse city, illustrated by the case of La Alianza, the aforementioned criteria are not resolved in its form, making other aspects more challenging to modify in the short and medium term. This is because achieving a certain degree of compactness, for example, involves increasing the built levels per parcel, which is only possible through the design and construction of new buildings, requiring the modification of the building height in the applicable regulations and potentially compromising resource efficiency if vertical construction surpasses a certain number of levels. In the case of variety, architectural styles reflect a specific urban memory (constituted in the long term) and contribute to generating multisensory experiences according to the characteristics of their elements. Returning to the proposed hypothesis, it can be inferred that while fine-grained aspects of urban form play an important role in mobility practices, they are not the sole explanatory factor of such practices. Social and socioeconomic representational dimensions also provide elements that help us understand them. In this context, it becomes evident that urban form shaped during the neoliberal period pose considerable challenges and thus requires greater efforts to foster active mobility. This is due to changes related to land uses –including the location of residential uses–, the distribution of land use purposes, the accessibility to amenities (urban services, infrastructure, and urban equipment), the degree of urban compactness, and the loss of place identity with the increasingly frequent emergence of the generic city. Such transformations have negatively impacted everyday mobility practices, as the trend toward active mobility is declining. For this reason, and due to the non-probability sampling method used, the analyzed cases should be considered as indicative – serving as starting point for more robust future analyses. These should be interpreted holistically, considering the concepts they represent as a whole and by considering their interconnections, all with the aim of developing a replicable methodology. A conclusive study will therefore require a more comprehensive version supported by a larger and more representative sample.

Recognizing the inherent difficulty of operationalizing issues such as social interaction, personalization, public space configuration, and urban image, the refined and complete version of this report will need to incorporate a measurement instrument grounded on hierarchical word recall techniques, more detailed and robust opinion analysis, and the perceptions of public space users and residents of the analyzed urban polygons. The use of Information and Communication Technologies (ICTs) in this latter task would enable a more efficient data collection to inform the evaluation of indicators. Regarding the hypothesis posed, urban form aspects initially considered fundamental will be retained in future directions of this work, but other variables will need to be also incorporated, including socioeconomic issues like income and age, and cultural issues –like the social representation of mobility modes– due to their potential to explain dominant practices. In this sense, the study will also consider developing profiles based on socioeconomic and demographic characteristics supported by ethnographic techniques, which will help explain the complexity of everyday mobility practices. Furthermore, to ensure the achievement of the proposed indicators, it will be crucial to rethink the current policy model regarding territorial planning, and specifically lad use, not only to promote greater diversity of lad uses but also to enable regulatory criteria that are effective at the micro-scale.