Mixed-use Neighborhoods Research Articles

Impact of building regulations on the perceived outdoor thermal comfort in the mixed-use neighbourhood of Chennai

The population in urban areas is increasing rapidly around the world in most of the cities. In India, this growth has forced the local governments to review the planning norms regularly with the main focus of making an affordable urban living. This resulted in increasing the built density without evaluating the effect of such developments on human thermal comfort. Outdoor microclimate is one of the significant factors that determine the quality of outdoor spaces. This study investigates the potential impact of the built geometry guided by the newly published development control rules of Chennai, India on the various parameters that influence microclimate. The existing and future scenario has been modelled for three locations in a typical mixed-use neighborhood of Chennai. Further, air temperature and relative humidity were measured in three locations on a typical summer month of May 2018. The recorded data was used for validating the simulated model and calibrating the model settings. Most of the studies on outdoor thermal comfort compare a base case scenario and project future scenarios. This paper is a more realistic comparison of outdoor thermal comfort between the actual resultant built environment guided by the new Tamil Nadu Combined Development and Building Rules, 2019 for selected locations and the existing built geometry which is the outcome of revised development control rules of 2013. The study found a significant reduction of 18 °C in mean radiant temperature (Tmrt) and a reduction of 12 °C in Physiological Equivalent Temperature (PET) between the 2013 and the predicted built geometry as per 2019 building rules. Further the duration of extreme heat stress in the Physiological Equivalent Temperature (PET) scale show a reduction of 3 h during the day time. The study will assist urban planners and designers to include outdoor thermal comfort also as an important factor while developing building rules.

Activity-friendly neighbourhoods can benefit non-communicable and infectious diseases

ABSTRACT Walkable, activity-friendly neighbourhoods are recommended for their benefits for non-communicable diseases, environmental sustainability, and economic performance. But how do activity-friendly neighbourhoods function during infectious disease pandemics like COVID-19? The spread of COVID-19 in some of the world’s dense cities has raised concerns about the risks of urban density and public transit. However, there are several pathways by which dense, mixed-use neighbourhoods with transit access and recreation facilities can reduce the risk of both infectious diseases and non-communicable diseases. Reducing health inequities is a core value for public health, and we comment on strategies for equitably creating activity-friendly communities.

The urban regeneration\u2019s framework for transit villages in Qatar: the case of Al Sadd in Doha

In the past two decades, Doha, the capital city of the State of Qatar, has undergone a rapid urban transformation. In 2013 and 2014, the State of Qatar, respectively, initiated the construction of Doha Metro and launched the Qatar National Development Framework (QNDF), an action plan for managing sustainable urban development at national level. Namely, QNDF emphasizes the importance of linking Doha Metro system with urban growth through transit-oriented developments (TODs), a model maximizing the integration between transport systems and land use, through the development of sustainable, vibrant, livable, compact and mixed-use communities. This research study focuses on Al Sadd, a mixed-use neighborhood located in the center of Doha. Al Sadd is considered a significant site for investigating the extent to which the TOD model can contribute to enhance standards of urban living and fostering a long-term urban sustainability. The strategy for monitoring and assessing the potential benefits of the investigated TOD is grounded on the on-site analysis (based on graph theory) of two indices: (1) built environment diversity and density and (2) travel behavior. The revealed comprehensive approach for the urban regeneration of the Al Sadd TOD is based on a framework for enhancing its (1) mixed-used urban fabric and (2) multimodal transportation systems. In turn, the proposed framework provides insights to move incrementally toward interdisciplinary research and governance for TOD in Qatar and in the globalizing GCC, through a long-term sustainability perspective.

Developing an optimization methodology for urban energy resources mix

This paper proposes a methodology to optimize the mixture of renewable and alternative energy resources, according to various neighborhood concepts, renewable energy settings and energy sources employed for the operation of buildings. Two neighborhood concepts are explored- a standalone neighborhood, which is independent from the local grid, and a grid-tied neighborhood, which can supply electricity to the grid as well as draw from it, depending on available energy generation from other sources. Renewable energy sources employed in the study consist of photovoltaic technology as well as wind turbines, while alternative energy sources consist of waste to energy. The proposed methodology is applied to a hypothetical mixed-use neighborhood representing a cold northern climate.The results indicate that an electric storage system is required, to achieve a net-zero energy, standalone neighborhood. This can reduce energy system size, which can be otherwise excessive (photovoltaic area can reach up to 280 times the area available in the neighborhood). For a grid-tied neighborhood, the grid can replace the storage system, reducing thus the size of renewable and alternative energy required to fulfill the energy demand. In such case, photovoltaic size can be reduced by up to 67% as compared to the standalone neighborhood, while wind turbines can be significantly reduced (by 85%) or completely eliminated.

The influence of neighborhood types on active transport in China’s growing cities

Rapid urban expansion in China has created both opportunities and challenges for promoting active transport in urban residential communities. Previous studies have shown that the urban form at the city scale has affected active transport in Chinese cities. However, there is less agreement about how the physical and social variations of neighborhood types should be addressed. This research investigates the four most representative neighborhood types found in Chinese cities: traditional mixed-use, slab block work-unit, gated community, and resettlement housing. Household travel diaries conducted in Chengdu in 2016 were analyzed using binary logistic regressions, supplemented by informal onsite interviews. The findings indicate significant variations in the use and accessibility of active transport in each neighborhood type for non-work trips. This suggests that each neighborhood type may need different strategies for promoting active transport: (1) the traditional mixed-use neighborhoods are in need of intensified urban retrofitting projects to reclaim public open space; (2) the work-unit could benefit from comprehensive plans rather than a patchwork of projects; (3) while opening up gated communities can improve porosity across neighborhoods and promote active transport, the more pressing issue may be their inability to keep up with the transportation needs of the residents; and (4) residents of resettlement housing should have better access to employment using transit and non-motorized modes.

Residential development patterns and child pedestrian injuries

A source of physical activity and independence, walking during childhood has many health and developmental benefits. Unfortunately, children are often not able to safely walk to their destinations, traffic safety being a primary barrier. The purpose of this paper is to understand how land use development patterns are related to safety outcomes for child pedestrians. Assuming that most child pedestrian trips start at home, this work explores the relationship between residential land use types and child pedestrian injuries. Are roadways in low-density residential areas more or less safe for child pedestrians than similar roadways in high-density residential areas or in mixed-use residential areas? We explore child pedestrian injury rates in Portland, Oregon through GIS spatial analysis and Bayesian spatial autoregressive Tobit models that use Markov chain Monte Carlo simulation with a Gibbs sampling scheme. Findings suggest that, with exposure and other socio-demographic factors being controlled for, roadways in mixed-use residential neighborhoods experience lower child pedestrian injury rates than high-density single-use neighborhoods or low-density single-use neighborhoods. Findings inform the Safe Systems approach and provide insight for the development of cities that ensure safety for vulnerable road users.

Effects of neighborhood environments on perceived risk of self-driving: evidence from the 2015 and 2017 Puget Sound Travel Surveys

Autonomous vehicles (AVs), with an expectation of improving road safety, are closer to becoming a reality. A large number of people are still concerned about how AVs would operate in real-life driving environments. The present paper investigates the factors that affect people’s views of the interactions between AVs and other road users based on a large sample from the 2015 and 2017 Puget Sound Travel Surveys. We specifically highlight the effects of the neighborhood environment and road infrastructure. We estimate a generalized ordered logit model to demonstrate the extent to which certain neighborhood environment and road infrastructure features affect individuals’ safety perceptions of AVs, controlling for demographics, daily travel patterns, and general interest in riding AVs. The results reveal that designated bicycle facilities are positively associated with individuals’ safety perceptions related to AVs. We find that residents from neighborhoods with more pedestrian facilities are more likely to express higher levels of concern on AVs’ capabilities to react to the environment. Our results also suggest that people living in mixed-use neighborhoods are more confident in sharing the road with AVs. The findings provide useful implications for effective policy interventions and infrastructure provisions that may affect the market penetration rates of AVs while keeping up the standards for other road users, such as bicyclists and pedestrians.

Optimization of the mixture of building types in a neighborhood and their energy and environmental performance

This paper presents optimization technique of residential and commercial buildings mixture within a mixed-use neighborhood, for enhanced energy performance and less GHG emission. The study, conducted for a Northern high latitude location, investigates several parameters related to building types, their density, floor area as well as ratio of specific building types to the total built area. Several methods are employed in the investigation, including energy simulations, statistical methods, optimization and decision making. A selection method of single optimal neighborhood scenario, based on the analysis of seasonal average hourly load is proposed. The results show that an optimal commercial to built land area ranges between 22% and 32%, with the remaining area dedicated to residential buildings. Multiple combinations of residential buildings that enhance energy performance while reducing GHG emissions are formed by 50% of detached houses and 50% of combined townhouses and apartment units (with different ratios). On the commercial side, near optimal combinations of commercial buildings area is constituted by 46–75% offices, 18–45% retails, and 6–9% supermarkets. Optimizing the hourly energy load profile, a scenario combining commercial land area of 25% with equal composition of office and retail buildings (47.5%), to residential area consisting of equal proportion of single detached and townhouses (48% each) can be selected.

Mobile-monitoring of Black Carbon and PM2.5 Air Pollution - Data only approach from Bangalore, India

OPS 46: Exposure assessment to air pollution in Asia and Africa, Room 315, Floor 3, August 27, 2019, 4:30 PM - 5:30 PM INTRODUCTION Mobile monitoring campaigns that repeatedly cover all roads in an area (“wall-to-wall driving”) have shown they can robustly capture spatial patterns in on-roadway pollution. Yet, this technique has not been tried in a low-income country. India is home to several of the world’s most polluted cities. We explore the potential for mobile monitoring to provide high-resolution exposure data in Indian cities. Methods: Our aim was to over-sample each location, thereby shedding light on how many measurements are needed to obtain robust estimates of concentrations at each location. Our mobile platform was equipped with an aethalometer for black carbon (BC) and an atmos for PM2.5. We sampled each location 45 times during September - December 2018. Monitoring consisted of 2025 vehicle-km (135 h) of measurement, across two neighborhoods: a mixed-use neighborhood (“MUN”; 15.4 km of road) and a residential neighborhood (“RN”; 18.8 km of road). Raw BC and PM2.5 measurements were corrected for common measurement artifacts. We then computed average concentration for each 30m road segment and used Monte Carlo sampling to develop synthetic datasets representing N driving sessions, where N = 1, 2, 4, 6 … 45 driving sessions. We compared average concentrations of the subsampled data-set against the entire 45-day dataset. Results: Mean (median) values (135 h of data) were 33 (18) µg/m3 in MUN, 29 (15) µg/m3 in RN for BC, and 43 (39) µg/m3 [MUN], 31 (39) µg/m3 [RN] for PM2.5. Monte-carlo subsampling for BC revealed R2 = 0.9 for ten rides, and diminishing returns for >10 rides; in contrast, for PM2.5, R2 ~ 0.6 for ten rides, with continued R2 improvement with more data (R2 >0.9 for >30 rides). Conclusion: Data-only approach may be more suitable for BC measurements in the Indian context.

An approach to perception mapping: using maps to investigate local user perceptions of urban quality in Hillevåg, Norway

ABSTRACTSpatial analyses map physical, geographic, demographic and functional characteristics of a place, while socio-cultural analyses investigate local social constructs. While the first might lack information on social, cultural and personal perceptions, the latter rarely relates needs or perceptions to the physical environment. This paper discusses the theoretical and methodological aspects of using subjective maps to collect user input and its value for further development. Map-based semi-structured interviews with local users were conducted in a mixed-use neighbourhood in Stavanger, Norway. The maps geo-reference points of strength, weakness, paths, barriers and representative space. The results were coherent with findings from other methods.

Influence of mixed-use neighborhood developments on the performance of waste-to-energy CHP plant

In this work, the influence of residential and commercial buildings on the performance of waste-to-energy (WtE) combined heat and power (CHP) plant, within a mixed-use neighborhood is quantified. The waste incinerator-based single and double stage CHP plants considered in study are modeled and simulated in Matlab-Simulink. The performance of WtE-CHP plant is evaluated based on hourly electricity and heat generations, heat extraction temperatures, and GHG emissions. The key results indicate that the use of single or double stage CHP plant is decided by various types commercial buildings, commercial land fraction, and commercial land to total area ratio. Considering a commercial land to total land area fraction of 0.25, two stage WtE-CHP plant can be used irrespective to varying proportions of residential buildings types and their unit densities. The heat extraction temperatures of 100–112 °C can be yielded for two stage CHP, whereas, for single stage CHP it lies between 170 and 180 °C. The GHG emissions for WtE-CHP plants decreases with the increase in proportions of offices, single detached houses, and townhouses. However, it increases with the increase fraction of retails and apartments. The energy generation to consumption fraction lies between 17 and 57% for conventional neighborhoods, whereas, for the high-performance neighborhoods it varies between 22 and 65%.

Mixed-use neighborhoods layout patterns: Impact on solar access and resilience

This study investigates the impact of overall layout of mixed-use neighborhoods on two main aspects of resilience. One aspect is the neighborhoods potential to capture solar radiation, affecting their capacity to exploit solar energy and thus dependence on the main grid. The other aspect is the vulnerability of the street network to natural disasters and local disruptions such as accidents. Three prototypes of neighborhood layouts are investigated. A rectangular neighborhood, serving as base-case, while the other prototypes include a circular layout, and a hexagonal-based layout. The built-up portions of all these neighborhoods are designed with the same characteristics, but with different number of nodes and street densities.The results indicate that maintaining optimal orientations of buildings (main façade facing south ± 30°), solar access is not significantly affected by the layout (less than 3% difference). The analysis of the street network resilience is evaluated through 6 indicators relating to centrality of its nodes and 5 indicators relating to efficiency and connectivity of the network. Results suggest the disruption response of the hexagonal and circular layouts exceeds that of the rectangular layout by the majority of indicators, with the hexagonal layout outperforming the circular by a narrow margin.

Understanding the effects of individual attitudes and residential neighborhood types on university commuters’ bicycling decisions

This study investigates the effects of individual perceptions and residential neighborhoods on university commuters’ bicycling decisions using the 2015 Ohio State University Travel Pattern Survey data. We generate eight attitudinal/perceptual components based on the 26 bicycling-related questions that capture detailed perceptions of commuters toward bicycling, neighborhood environments, and residential location choice. We create distinct neighborhood typologies combining land use and socioeconomic characteristics, including population, employment, housing and intersection densities, housing types, median age of housing stock, and median household income. Probit regression models are estimated to assess the effects of sociodemographic, attitudinal/perceptual components and neighborhood types while accounting for the residential self-selection effect. Results show that people residing in different neighborhood types reveal significant attitudinal differences in terms of their conditional willingness to bicycle, and evaluation of bicycle friendliness of neighborhoods and routes. We find that bicyclists are more likely to live in neighborhoods that they perceive as having good-quality for bicycling in terms of access to bicycle facilities and lower traffic levels. Results also show the significant association of neighborhood types with bicycle commuting outcomes. People from medium-density, mixed-use, and suburban single-family neighborhoods are less likely to commute by bicycle as compared to those from high-density, mixed-use neighborhoods.

Sluisbuurt Amsterdam: werelderfgoed en hoogbouw

‘Sluisbuurt’ Amsterdam: world heritage and high-rise buildings On the northwestern part of the Zeeburgereiland, an island in the IJ, the municipality of Amsterdam is developing the Sluisbuurt quarter: a mixed-use neighbourhood with shops, offices, catering and education and no less than 5,500 residential units, some of which are high-rise. The Sluisbuurt soon proved controversial because of the visibility of the towers from the Amsterdam city centre and from the rural area around Waterland. In this article we discuss the planning and the history of the island.

What "Moves" the Populations Most Likely to Be Physically Inactive-Women and Older Adults? Evidence From Mueller, a Mixed-Use Neighborhood in Austin, Texas.

Older age groups are less likely than their younger counterparts to be regularly active and women are even less active. Ecological models suggest that multiple levels of influence with each level influencing the next level impacts physical activity behaviors. Hierarchical multiple regressions were used to determine factors within and across the ecological model that predicted both total physical activity and walking for recreation. The overall predictors of total physical activity were different than those of walking for recreation, with the exception of dog ownership and perceived barriers. Gender and age were significant predictors of walking for recreation, but these associations were not present for total physical activity. Women and older adults walked more for recreation in a mixed-use community, Mueller, (and thus engaged in more total physical activity) compared with men and younger adults. Behavior-specific physical activity as well as total physical activity led to a better understanding of factors that may impact behavior among an overall aging population, especially women. This level of specificity is important in understanding specific factors that are associated with physical activity among vulnerable populations and can help guide the development of tailored, cost-effective, and efficient policies and interventions.

Objectively-assessed neighbourhood destination accessibility and physical activity in adults from 10 countries: An analysis of moderators and perceptions as mediators

RationaleResidents of neighbourhoods with high destination accessibility (higher population density, more-interconnected streets, and better access to services, public transport and parks) are more physically active. Evidence on the factors that underlie these associations is sparse and inconsistent. ObjectiveWe examined (1) five socio-demographic and four non-destination perceived neighbourhood attributes as moderators of the relationship between objectively-assessed destination accessibility and moderate-to-vigorous physical activity (MVPA); (2) perceived indicators of destination accessibility as mediators of those relationships; and, (3) the generalizability of findings across 14 cities. MethodsData were from the International Physical Activity and Environment Network (IPEN) Adult study (N = 6822), which provided comparable objective and perceived environmental variables and accelerometer-based MVPA from 14 cities across 10 countries. Mediation and mediation moderation analyses were performed. ResultsObjective net residential density, public transport density, and number of parks in the neighbourhood were consistently associated with MVPA across all examined socio-demographic groups and non-destination perceived neighbourhood characteristics. However, only the association between number of parks and MVPA was mediated by its conceptually-comparable perceived indicator. While the associations of objective intersection density and land use mix with MVPA were moderated by both gender and perceived pedestrian infrastructure/safety, only the latter moderating effects were mediated by the conceptually-comparable perceived indicators. Perceived neighbourhood safety and/or aesthetics moderated the associations of objective ratio of retail/civic land to total area and distance to nearest transport stop with MVPA. These associations were not mediated by the conceptually-comparable perceived indicators. ConclusionDensely populated neighbourhoods with access to public transport and parks have the potential to significantly and equitably contribute to adults' MVPA on a global scale. Perceived neighbourhood aesthetics, pedestrian-friendliness and safety can magnify the positive effects of mixed-use neighbourhoods on residents' MVPA by interacting with the perceived ease of access to a variety of destinations.

Promises and perils of collective land tenure in promoting urban resilience: Learning from China's urban villages

New frameworks for “urban resilience” frequently overlook the role of property rights and tenure security in shaping vulnerability, as well as how different property rights regimes shape societal capacity to adapt to environmental and developmental disruptions. We contribute to these discussions by examining how collective urban land tenure affects community-scale resilience, defined as environmental wellbeing, productive livelihoods, and empowered governance. We use urban villages in Shenzhen to study how this widespread phenomenon of collective land ownership in Chinese cities allowed rural villagers to adapt as cities spread around them over time. Drawing on a literature review, interviews, and a field visit to Shenzhen, we find that collective tenure in Shenzhen’s urban villages has helped them avoid some of the limitations seen in household-level tenure formalization efforts elsewhere. Collective tenure enabled rural villages to create self-governance mechanisms that allowed them to transform individual and collective assets into vibrant, well-serviced, and mixed-use neighborhoods. Urban villages house most of Shenzhen’s residents and have helped underwrite the region’s industrialization process. However, collective tenure also has hindered integration with Shenzhen’s urban infrastructure, governance, and taxation systems, resulted in astronomical profits for village elites, and repeated historic patterns of unequal land ownership in China. The promises and perils of collective urban property rights seen in Shenzhen call for research on other such models around the world to further inform whether and how such property rights regimes can support equitable and holistic notions of urban resilience.

Putting rooftops to use – A Cost-Benefit Analysis of food production vs. energy generation under Mediterranean climates

In today's growing cities, where land is an expensive commodity and direct exposure to sunlight is a valuable asset, rooftops constitute vast underexploited areas. Particularly with growing urban environmental concerns, the potential of transforming these areas into productive spaces – either for food cultivation or energy generation – has emerged as a viable option in recent years. Both food production and energy generation have benefits in the urban environment. Rooftop farming is an environmentally and economically sustainable way of exploiting urban rooftops, reducing “food miles” and providing local jobs, while roof-integrated solar photovoltaic (PV) modules provide clean energy, are increasingly cost-effective, and offer job opportunities. In both cases, a rooftop network of production could directly supply a portion of a necessary resource – either food or electricity – to the local community while concurrently reducing the burden on the environment. To provide a basis for comparing the implementation of these productive uses of rooftops in Mediterranean cities, this article applies a Cost-Benefit Analysis (CBA) to a mixed-use neighborhood located in Lisbon to assess the following uses: (1) open-air rooftop farming on intensive green roofs; (2) food production in low-tech unconditioned Rooftop Greenhouse (RG) farms; (3) Controlled-Environment Agriculture (CEA) in high-tech RG farms; and (4) solar PV energy generation. Relative costs, cost-saving benefits and added value of these four alternative productive uses of rooftops were modeled over 50 years and deducted from present value, considering two levels of analysis: (a) effects directly incurred by the operator of the systems; and (b) societal effects on the local community. To the authors' knowledge, this is the first comprehensive comparison of rooftop PV versus rooftop farming technologies. The results have shown food production to be more beneficial than energy generation, for both the owner of the system and the local community, under the modeled conditions and given the selected items of comparison. In particular, the results show that rooftop greenhouse farming can provide significant benefits over rooftop green roof and solar PV systems when assessed from a holistic perspective that accounts for impacts on both the operator and the local community.

Privatisation of the Production of Public Space

Privatisation of the Production of Public Space

Coupling optimization of urban spatial structure and neighborhood-scale distributed energy systems

When planning a neighborhood-scale distributed energy system (NDES), enough attention should be paid to the urban spatial structure, which may affect not only the system configuration on the supply side but also the load profiles on the demand side as well as their interactions. In this study, a novel nonlinear optimization model is developed for the determination of neighborhood design and NDES arrangement in terms of energy-saving aspect. By executing the optimization model, besides the configuration of energy supply technology, optimal building mix within the neighborhood can be also deduced. As an illustrative example, a mixed-use neighborhood located in Shanghai, China has been assumed for analysis. According to the simulation results, the introduction of NDES may achieve satisfied energy-saving benefits. Although additional energy consumption including heat loss and pump power may be encountered in the NDES, it can be offset through rational plan of the urban spatial structure and its cooperation with the supply side. For a fixed building mix, the reduction of supply radius may lead to better energy performance. Moreover, there exists the maximum supply radius over which, the NDES will not be recommended from the energy-saving viewpoint.