Several cities around the world have changed their transportation planning paradigm, understanding that the prime goal is to provide access to opportunities for everyone. To address this goal, public ...transport plays a fundamental role and, therefore, it is key for developing a sustainable and equitable city.
This paper proposes a methodology to analyze access to opportunities through public transport incorporating the user's valuation of attributes that impact the level of service on his/her trip and the competitiveness for urban opportunities. Using data from Santiago, Chile, we applied the proposed methodology to analyze accessibility to higher-quality public primary schools. We compare total travel time (TTT) with a proposed measure of total generalized travel time (TGTT) using simple potential and competitive accessibility indicators, accounting for the subjective valuation of walking time, travel time, waiting time, comfort and transfers, and translating them into in-vehicle time units.
We find that the inclusion of competition has a more substantial impact than including the subjective valuation of the level of service in the accessibility to educational opportunities. Using competitive measures with TGTT, we found that around 20% of the zones in Santiago have at least a 50% deficit of higher-quality public education, and 71% of them are in peripheral areas. Furthermore, these zones, where medium and low-income population usually lives, can experience, on average, 1–2 transfers, 4–5 passengers per square meter, and 15-min waiting. We conclude that the proposed methodology provides a more comprehensive way to understand accessibility by incorporating the traveling experience, allowing to determine how and where to intervene to effectively improve accessibility, with a focus on urban equity.
•We propose a new methodology to analyze accessibility through public transport•We incorporate the user's valuation of the level of service attributes and the competitiveness for educational opportunities•Worse-off people experience 1‐–2 transfers, 4–5 pax/sqm and 15-min waiting•20% of Santiago's zones have at least 50% deficit of higher-quality public education•71% of them are where most medium and low-income population lives
Housing and transport affordability (H + TA) analysis has been receiving increasing attention among academics and practitioners worldwide, particularly in Global North settings. These studies usually ...overlook spatial and socioeconomic distributional considerations that potentially underestimate the simultaneous impact of transport and housing costs on lower-income family budgets. Our work seeks to address these knowledge gaps by understanding and measuring H + TA, considering different types of households in Santiago, Chile. Combining income, housing, transport, and census data, we estimate H + TA costs using spatial clusters and probability distribution functions, analyzing the “degree of choice” that socially disadvantaged groups have given their financial constraints. The results show that families with children, the elderly, and immigrants are among the most limited in their choices. Most central and eastern sectors of the city which provide the highest density of work opportunities are out of reach for the three lowest-income deciles given the high combined costs of H + TA, being dependents on government benefits and/or social housing. Middle class, from the 4th to 6th income deciles, can choose from between 30% and 65% of all housing and transport combinations, but from less than 6% of those offered on the two clusters with the best transport and urban conditions. These findings bring into question current inter-sectoral policies to alleviate the “cost pressure” of Santiago's lower- and middle-income households.
The quantitative measurement of accessibility through public transport has become more complex and accurate over time. However, it lacks many of the deeper nuances of how people actually experience ...their travel environments. Our previous works have highlighted the importance of incorporating the lived travel experiences of passengers within accessibility indicators, considering the quality of the walking environment and different attributes of the public transport services.
Building on these works, this mixed-method research seeks to further improve the characterization of accessibility according to users' travel experiences, as described by those attributes that inhibit or enhance access to opportunities within the city. We use content analysis of focus groups, data gathered in a brief survey and sociodemographic and public transport data for our analyses. Our main contributions are (i) to develop a conceptual framework to analyze qualitative data on how people relate and discuss their public transport accessibility experiences and (ii) to develop accessibility indicators differentiating user perceptions. We apply this novel conceptual framework and methods to the unique urban morphology of two municipalities of Santiago de Chile.
We identified different ‘socially constructed’ narratives for buses and metro. The participants focused on barriers to accessibility, showing an important relationship between them, as well as substantial differences in their overarching positive perception of metro and negative for buses. However, when disaggregating the analysis by primary transport mode and location, we found ‘hidden’ values for buses, recognizing its capillarity and underlying connectivity with the metro system. Furthermore, we found a dissimilar perception of transport environments when disaggregating the analysis by gender, age and location, which translated into different accessibility profiles for the various public transport users. From these experiential qualitative perspectives, it was thus possible to determine some attributes that had been previously overlooked in more quantitative studies but which are important when analyzing public transport accessibility for different population groups.
•We found interrelation among accessibility barriers, especially between vulnerable people•We found a ‘hidden’ value for buses, particularly among public transport users•We identified different ‘socially constructed’ narratives for buses and metro•We found a dissimilar perception of transport environment by gender, age and location•We measured different accessibility profiles for the various public transport users
The primary objective of this study was to analyze the psychometric properties of the
(IIA-PRF) of Reference Guide III proposed in NOM-035-STPS-2018. A total of 2,149 workers in Baja California, ...Mexico's
and
sectors, were administered an online inventory version. Preliminary analyses were performed, as well as a Confirmatory Factor Analysis (CFA) based on two models proposed by the standard itself: an eight-factor model (8-FM) and a four-factor model (4-FM). Likewise, based on the results and with the recommendations of the specialists, a threefactor model (3-FM) was proposed. In addition, nested model sequencing methods were subsequently applied to validate the invariance between the origin of the activity. The dimensionality of 3-FM was found to have adequate fit values according to a-priori established criteria. It is concluded that the IIAPRF does not have the reliability and validity parameters necessary to support interpretations, uses and consequences based on the theoretical structure established by NOM-035-STPS-2018 and that, although the 3-FM presents better reliability and validity indices, it is not invariant in terms of the origin of the activity. Finally, we discuss the implications and recommend reviewing and adjusting the design of the IIAPRF items to extend the measurement of invariance to other groups of relevance for decision making in the improvement of the work environment.
A central issue in urban inequity has to do with distributive justice in the costs and benefits associated with urban transport, and whether certain population groups are systematically disadvantaged ...about mobility, accessibility, affordability, and externalities, the preponderant factors in transport poverty. This article proposes a methodology for analyzing how investment in transport infrastructure and non-housing construction, mobility levels (trip distances, times, and speeds) and the associated trip costs (monetary, accidents, pollution, and energy consumption) are distributed across the different socioeconomic quintiles of a city. The methodology was applied to the real-world case of Santiago de Chile. The results showed that compared with the lowest income quintile, people in the highest income quintile made 1.2 times more trips at an average speed 1.6 times higher. In relation to costs, the richest quintile generated 6.7 times as much pollution and used 7 times as much energy but consumed a significantly lower share of their income (10% vs. 45%). In addition, the top quintile was the beneficiary of 2.5 times more investment in both transport infrastructure and new construction space for commercial activities and services over the period considered. Finally, private car use in the top quintile was 5.3 times greater. This transport mode accounts for 6.8 times more of the accident rate than public transport, bicycles, or walking combined. This clearly inequitable scenario points to the needs for progressive policies that target lower income groups and promote a more rational use of cars in view of their negative impacts on the city.
Most studies of public transport accessibility have focused on proximity to stops, walking distances or time to reach them. This approach ignores other accessibility barriers, such as the quality of ...the urban environment of these walks. The aim of this research is to analyze both accessibility to public transport stops and the quality of the urban walking environment, exploring fairness issues across the city in terms of these two dimensions. The proposed methodology considers the definition of two indicators: walking accessibility to public transport stops and quality of the walking environment, considering different attributes and dimensions. These indicators are later used to develop a fairness analysis at the local and metropolitan level, using Lorenz curves, Gini coefficient, and Foster-Greer-Thorbecke (FGT) poverty measures. A diagnosis based on these indicators for Santiago de Chile allows us to suggest public policy priorities to improve accessibility to public transport and promote modal shift. The results show that 12 out of 34 municipalities in Santiago are deprived of one or both dimensions, not managing to achieve minimum fairness standards. Moreover, since a correlation between low income and poor access and urban space quality is detected, urban fairness across the city would benefit from centralized urban policies not depending on the budget of each administrative division.
Latin America is a highly urbanized region characterized by remarkable inequality levels, also reflected in an uneven distribution of opportunities, making socio-economic segregation quite visible. ...Since the individual possibility to travel and therefore access to urban opportunities strongly depends on socio-economic status and the distances to overcome, highly unequal patterns of mobility and accessibility emerge. The continuous expansion of Latin American cities originates specific mobility-related inequalities visible in periurban areas, which tend to lack some key urban opportunities and public transport services usually available in cities. Due to established and new patterns of territorial segregation, these areas may generate new forms of marginality in relation to mobility, posing challenges for public action and territorial governance. Our paper considers if and how periurban areas experience different forms of mobility-related inequalities in three Latin American metropolises in Brazil, Chile, and Colombia (São Paulo, Santiago, and Bogotá, respectively). We do so by examining the differences among urban core and periurban zones based on four elements: socio-demographic features, access to the public transport system, spatial continuity, and functional dependence. Our analysis shows that the three metropolitan regions have different structures: while Bogotá and Santiago appear to be more dependent on the urban core, São Paulo shows more autonomous and self-sufficient periurban zones. The analysis also highlights different forms of peripherality, defined by differentiated mobility patterns and modal choices that suggest that city-specific lines for public action might be needed.
Monopile foundations are known as the most common foundation solution for offshore wind turbines (OWTs). However, the state of practice for designing monopile foundations in high seismicity areas is ...still limited. In particular, the impact of soil liquefaction on the seismic soil-foundation-OWT interaction is not yet well understood. In this paper, three-dimensional (3D), fully-coupled, nonlinear finite-element analyses performed in the OpenSees numerical platform were used to evaluate the seismic performance of a series of hypothetical 5 MW OWTs on monopile foundations in layered, liquefiable sites. A suite of earthquake recordings with and without strong velocity pulses (i.e., near fault, pulse-like and ordinary motions, respectively) was used to investigate the impact of ground motion characteristics on the seismic response of the OWT system. Also, the influence of soil-structure interaction and earthquake shaking coupled with extreme environmental loading (i.e., wind and wave loads) on the seismic performance of soil-OWT systems was evaluated. The numerical results showed pile movements induced by extreme climate loading led to a bias in permanent settlement accumulation across the foundation area and accumulation of soil deformations in the proximity of the pile. Ground motion velocity pulses increased the cyclic stress demand in soil and, therefore, the potential for the occurrence of soil liquefaction. A subsequent, limited numerical sensitivity study showed that the foundation rotations of the OWT system were influenced by ground motion characteristics such as polarity and velocity pulses, and the presence of the wind and wave loads. The cumulative absolute velocity (CAV) was identified as the optimum ground motion intensity measure for permanent foundation settlement and tilt as well as for peak transient foundation tilt of the OWT system under extreme environmental loadings. The net outcome of these factors determined the magnitude and orientation of the foundation rotations at the end of shaking. This study highlights the importance of considering the effects of extreme loadings and pulse-like motions in the design and performance of OWT systems.
•The impact of soil-structure interaction as well as the coupling of earthquake shaking with extreme environmental loadings (i.e., wind and wave loads) on the seismic performance of soil-OWT systems were evaluated.•The presence of wind and wave loads increased the bias in permanent settlement across the foundation footprint area and the accumulation of soil deformations near the pile.•The presence of velocity pulses in the input ground motion increased the cyclic stress ratio of soil layers, enhancing the potential for soil liquefaction in both loose and dense sand layers.•The cumulative absolute velocity (CAV) was identified as the optimum ground motion intensity measure for permanent foundation settlement and tilt as well as for peak transient foundation tilt of the OWT system under extreme environmental loadings.•The numerical results showed that the magnitude and orientation of foundation rotations were a net outcome of ground motion characteristics (in terms of polarity and velocity pulse) and the presence of the extreme environment loads.
Current guidelines for evaluating the performance of ground densification as a liquefaction countermeasure near buildings are based on free-field conditions or, at best, consider one structure ...experiencing soil-structure interaction (SSI) in isolation. However, in urban areas, where structures are constructed in close vicinity of each other, structure-soil-structure interaction in liquefiable deposits near two (SSSI2) or multiple (≥3) buildings in a cluster (SSSI3+) has been shown as consequential on key engineering demand parameters (EDPs), particularly differential settlement. Furthermore, the potential tradeoffs associated with ground improvement in urban settings, considering SSSI2 and SSSI3+, are currently not well understood or defined. In this paper, three-dimensional (3D), fully-coupled, nonlinear, dynamic finite element analyses are first validated with centrifuge models of SSI and SSSI2, including ground densification. These models are subsequently used to explore the influence of building arrangement (two adjacent structures and four structures in a square block) and spacing on key EDPs for mitigated structures undergoing SSSI2 and SSSI3+ compared to that under isolated SSI. For the conditions evaluated, it is shown that both SSSI2 and SSSI3+ could reduce the average settlement of mitigated structures compared to SSI at building spacings (S) > 0.5Wfnd (where Wfnd is the foundation width), particularly in larger clusters experiencing SSSI3+. On the other hand, both SSSI2 and SSSI3+ amplified the permanent tilt of the mitigated structures compared to SSI at S < 0.5Wfnd. The impact of these interactions on tilt reduced at larger spacings. A limited, subsequent numerical sensitivity study showed that pulse-like input motions together with the stress and flow-path bias introduced by SSSI2 and SSSI3+ can increase the uneven accumulation of soil strains below the mitigated structures compared to cases experiencing SSI or the same building clusters subject to non-pulse-like motions. This led to a greater amplification in tilt of mitigated structures experiencing SSSI2 and SSSI3+ at shorter spacings under the selected pulse-like motions. Overall, the results point to the importance of considering the impact of building cluster arrangement, spacing, soil and structural properties, and ground motion characteristics in the design of ground improvement in urban settings.
•Multiple SSSI could reduce the settlement of treated structures compared to SSI at greater building spacings.•Multiple SSSI amplified the permanent foundation tilt compared to SSI at shorter building spacings.•The pulse-like input motions together with multiple SSSI can increase the uneven accumulation of soil strains below the foundations.•The pulse-like motions together with multiple SSSI may lead to a greater amplification in foundation tilts at shorter spacings.•Multiple SSSI plays an important role that control the performance and damage of mitigated structures in urban settings.
