Street Network Configuration Research Articles

Understanding Chinese Urban Form: The Universal Fractal Pattern of Street Networks over 298 Cities

Urban form can be reflected by many city elements, such as streets. A street network serves as the backbone of a city and reflects a city’s physical structure. A street network’s topological measures and statistical distributions have been widely investigated in recent years, but previous studies have seldom characterized the heavy-tailed distribution of street connectivities from a fractal perspective. The long-tail distribution of street connectivities can be fractal under the new, third definition: a set or pattern is fractal if the scaling of far more small things than large ones recurs at least twice. The number of recurred scaling patterns of far more less-connected streets than well-connected ones greatly helps in measuring the scaling hierarchy of a street network. Moreover, it enables us to examine the potential fractality of urban street networks at the national scale. In this connection, the present study aims to contribute to urban morphology in China through the investigation of the ubiquity of fractal cities from the lens of street networks. To do this, we generate hundreds of thousands of natural streets from about 4.5 million street segments over 298 Chinese cities and adopted power-law detection as well as three fractal metrics that emerged from the third definition of fractal. The results show that almost all cities bear a fractal structure in terms of street connectivities. Furthermore, our multiple regression analysis suggests that the fractality of street networks is positively correlated with urban socioeconomic status and negatively correlated with energy consumption. Therefore, the fractal metrics can be a useful supplement to traditional street-network configuration measures such as street lengths.

Home and school environmental correlates of childhood BMI

BackgrouandActive commuting to school can be a substantial opportunity to provide the necessary daily physical activity for children and to counteract childhood obesity. This paper examines the associations of urban form, in general, and street network design, in particular, with body mass index (BMI) in children aged between 12 and 16, controlling for socio-economic features (gender, educational attainment, income, and auto ownership) and daily physical activity (access mode to/from school and walking behaviour). MethodsData were drawn from questionnaires conducted in 20 elementary schools located in the Anatolian part of İstanbul, Turkey. Randomly selected 6th, 7th, and 8th grade students (N = 1784) completed questionnaires regarding their commuting modes to/from school while their parents (N = 1118) completed questionnaires about their socio-economic characteristics and their children's daily physical activity. Each student's BMI was calculated by measured height and weight data. Home- and school-environments (800-and 1600-m buffers around the respondent and school) were evaluated through GIS-based land-use data and segment-based street connectivity measures. Selected street segments within school-environments were also audited with regard to pedestrian environment characteristics. ResultsFindings indicate that children who actively commuted to/from school had lower BMIs than non-active commuters. More importantly, it is shown that increased street network connectivity measured at the segment-level is significantly associated with reduced BMI in school children. In fact, connectivity measures appear to be the strongest correlates of BMI. ConclusionsThis study provides important evidence for planners, urban designers, and policy makers on the significance of built environment, in general, and street network configuration, in particular, within home- and school-environments. One rule of thumb would be to design a well-connected street network with relatively denser connections and reduced direction changes within the neighbourhood – not only within a couple of blocks of homes and schools but also within their larger fabric (800–1600 mt buffers).

The influence of street network configuration on sexual harassment patterns in Cairo

Sexual harassment is a common experience for women in urban spaces. While many studies have shown the types of urban environments that are hostile to women, limited research has examined the empirical relationship between sexual harassment and the configuration of the street network. This study uses crowdsourced data and space syntax analysis to investigate the relationship of the frequency of sexual harassment to the proximity of such incidents to main streets in the central business district of Cairo, Egypt. The results show that harassment incidents are associated with street segments with high volumes of foot traffic. Unsafe space usually lacks a balanced co-presence of males and females where the former outnumber the latter. The article advances our knowledge of visibility and spatial accessibility characteristics of sexual harassment incidents and the potential impacts of urban design and planning policies on women's power and fragility.

Understanding the role of urban form in explaining transportation and recreational walking among children in a logistic GWR model: A spatial analysis in Istanbul, Turkey

This study aims to examine associations between urban form factors generally, and street network configuration in particular, and walking for different purposes among children in Istanbul, Turkey. Parents of randomly selected students (ages 12–16) at 20 middle schools (N = 917) completed questionnaires about their socio-economic characteristics and the frequency of their children's walking for recreational and for transportation purposes in their neighbourhood during a typical day. The environment around 400 m of participants' homes was evaluated through GIS-based parcel-level land-use data and segment-based street connectivity measures calculated using space syntax techniques. Logistic geographically weighted regression models were estimated to measure the desired associations while adjusting for socio-economic characteristics. Results demonstrate a marginal association between urban form measures and walking behaviour but only in certain peripheral parts of the city. More importantly, increased directional accessibility, which identifies the extent to which more street length is accessible within few direction changes, is associated with higher odds of recreational walking in particular areas where a strong differentiation between scales of street connectivity structure is evident such as a supergrid of primary roads with inserted organic local streets. In addition, children residing in neighbourhoods with reduced residential density and increased commercial and recreational activities are more likely to walk for transportation purposes. The findings of this study demonstrate that the one-size-fits-all approach may not effectively encourage walking. Urban areas tend to have varying qualities that need to be handled uniquely, and therefore targeted rather than blanket interventions regarding the design of neighbourhoods around schools and homes may be beneficial in supporting walking behaviour of children.

The Regaining of Traditional Street: Combining Street Network Configuration with Temporary Urban Interventions

Observations and Axial analysis models are combined into Space Syntax to study the corresponding relationship between a street network and how temporary urban interventions in a traditional shopping street in Little India, Kuala Lumpur, may affect public life. Little India was chosen as the case study because of its historical and cultural significance. The study aims to explore the most important temporary urban interventions - activity-based interventions in traditional shopping street through the spatial logic of street network. Static snapshots and people-following were conducted in Little India, to observe activity and movement during a whole day on a weekday and a weekend day. Two (2) parameters in Space Syntax were chosen including global integration and local integration to measure its urban interventions, activities, and movement among visitors in traditional shopping streets. The result indicates that there is a certain correlation among these parameters with the following spatial configurative analyses; all lines analyses and segment based angular analyses. It finds significant relationships between global integration and local integration, and the activity pattern. It is proposed in this paper that streets with a high degree of integration and adjacent to main streets; Jalan Tun Sambanthan is a key factor for carrying forward temporary urban interventions in Little India. More attention should be paid to the street network to preserve diversity, make the streets active, and importantly to improve public life.

Spatial information and the legibility of urban form: Big data in urban morphology

Urban planning and morphology have relied on analytical cartography and visual communication tools for centuries to illustrate spatial patterns, conceptualize proposed designs, compare alternatives, and engage the public. Classic urban form visualizations – from Giambattista Nolli’s ichnographic maps of Rome to Allan Jacobs’s figure-ground diagrams of city streets – have compressed physical urban complexity into easily comprehensible information artifacts. Today we can enhance these traditional workflows through the Smart Cities paradigm of understanding cities via user-generated content and harvested data in an information management context. New spatial technology platforms and big data offer new lenses to understand, evaluate, monitor, and manage urban form and evolution. This paper builds on the theoretical framework of visual cultures in urban planning and morphology to introduce and situate computational data science processes for exploring urban fabric patterns and spatial order. It demonstrates these workflows with OSMnx and data from OpenStreetMap, a collaborative spatial information system and mapping platform, to examine street network patterns, orientations, and configurations in different study sites around the world, considering what these reveal about the urban fabric. The age of ubiquitous urban data and computational toolkits opens up a new era of worldwide urban form analysis from integrated quantitative and qualitative perspectives.

Pathways: Examining Street Network Configurations, Structural Characteristics and Spatial Crime Patterns in Street Segments

Although theories suggest that street network configurations (pathways) are important factors for understanding the spatial patterns of crime, relatively less attention has been paid to the association between the physical configuration of the street network and the level of crime in place. Consequently, we employed the concept of betweenness centrality in the context of the street network to empirically measure the potential foot traffic passing through a given street segment. We introduce a methodological refinement by accounting for the characteristics of origin and destination of each potential trip (where travelers are from and tend to go) using residential population in origins and destinations and the number of various types of business employees in destinations. Moreover, we posit that the effect of potential foot traffic into a given street segment will be moderated by certain social environmental characteristics such as socioeconomic status of place. By using data on a sample of 300,000 street segments in the Southern California region across 130 cities, we estimate a set of negative binomial regression models including the betweenness measures. Our results show that betweenness centrality has a curvilinear relationship with violent and property crime: At lower levels, increases in betweenness results in increased crime, yet the pattern becomes crime-reducing at higher values of the betweenness measure. We also found that the pattern is moderated by the socioeconomic status of the street segment. The current study highlights that there is an important relationship of the physical environment in terms of the street network configuration and crime in street segments.

Urban spatial order: street network orientation, configuration, and entropy

Street networks may be planned according to clear organizing principles or they may evolve organically through accretion, but their configurations and orientations help define a city’s spatial logic and order. Measures of entropy reveal a city’s streets’ order and disorder. Past studies have explored individual cases of orientation and entropy, but little is known about broader patterns and trends worldwide. This study examines street network orientation, configuration, and entropy in 100 cities around the world using OpenStreetMap data and OSMnx. It measures the entropy of street bearings in weighted and unweighted network models, along with each city’s typical street segment length, average circuity, average node degree, and the network’s proportions of four-way intersections and dead-ends. It also develops a new indicator of orientation-order that quantifies how a city’s street network follows the geometric ordering logic of a single grid. A cluster analysis is performed to explore similarities and differences among these study sites in multiple dimensions. Significant statistical relationships exist between city orientation-order and other indicators of spatial order, including street circuity and measures of connectedness. On average, US/Canadian study sites are far more grid-like than those elsewhere, exhibiting less entropy and circuity. These indicators, taken in concert, help reveal the extent and nuance of the grid. These methods demonstrate automatic, scalable, reproducible tools to empirically measure and visualize city spatial order, illustrating complex urban transportation system patterns and configurations around the world.

Exploring the influence of road network structure on the spatial behaviour of cyclists using crowdsourced data

This study explores the effect of the spatial configuration of street networks on movement patterns of users of a cycling monitoring app, employing crowdsourced information from OpenStreetMap and S...

Comparative Associations of Street Network Design, Streetscape Attributes and Land-Use Characteristics on Pedestrian Flows in Peripheral Neighbourhoods.

Research has sufficiently documented the built environment correlates of walking. However, evidence is limited in investigating the comparative associations of micro- (streetscape features) and macro-level (street network design and land-use) environmental measures with pedestrian movement. This study explores the relative association of street-level design-local qualities of street environment-, street network configuration –spatial structure of the urban grid- and land-use patterns with the distribution of pedestrian flows in peripheral neighbourhoods. Street design attributes and ground-floor land-uses are obtained through field surveys while street network configuration is evaluated through space syntax measures. The statistical models indicate that the overall spatial configuration of street network proves to be a stronger correlate of walking than local street-level attributes while only average sidewalk width appears to be a significant correlate of walking among the streetscape measures. However, the most significant and consistent correlate of the distribution of flows is the number of recreational uses at the segment-level. This study contributes to the literature by offering insights into the comparative roles of urban design qualities of the street environment and street network layout on pedestrian movement. The findings also offer evidence-based strategies to inform specific urban design and urban master planning decisions (i.e., the provision of more generous sidewalks on streets with relatively higher directional accessibility) in creating lively, walkable environments.

Spatial Information and the Legibility of Urban Form: Big Data in Urban Morphology

Urban planning and morphology have relied on analytical cartography and visual communication tools for centuries to illustrate spatial patterns, propose designs, compare alternatives, and engage the public. Classic urban form visualizations – from Giambattista Nolli’s ichnographic maps of Rome to Allan Jacobs’s figure-ground diagrams of city streets – have compressed physical urban complexity into easily comprehensible information artifacts. Today we can enhance these traditional workflows through the Smart Cities paradigm of understanding cities via user-generated content and harvested data in an information management context. New spatial technology platforms and big data offer new lenses to understand, evaluate, monitor, and manage urban form and evolution. This paper builds on the theoretical framework of visual cultures in urban planning and morphology to introduce and situate computational data science processes for exploring urban fabric patterns and spatial order. It demonstrates these workflows with OSMnx and data from OpenStreetMap, a collaborative spatial information system and mapping platform, to examine street network patterns, orientations, and configurations in different study sites around the world, considering what these reveal about the urban fabric. The age of ubiquitous urban data and computational toolkits opens up a new era of worldwide urban form analysis from integrated quantitative and qualitative perspectives.

Intercomparison of two modeling approaches for traffic air pollution in street canyons

We present an intercomparison of two models applied to a major boulevard in a Paris suburb accounting for building effects: (1) a computational fluid dynamics (CFD) model providing a detailed three-dimensional representation of the atmospheric flow and pollutant dispersion (Code_Saturne) and (2) a street-network model with well-mixed steady-state concentrations within street segments coupled with a regional chemical-transport model (SinG). Simulations were performed for five cases representing different meteorological conditions (wind direction and speed) and two sensitivity cases with different emissions. We compare model results to measurements of NOx at two monitoring stations on either side of the street. Results exhibit (a) a complex behavior highlighting effects of the street-network configuration and emission patterns on the cross-street concentration gradient and (b) a satisfactory performance with assumption of well-mixed concentrations within street-canyons for mean NOx (MNE of 39% and 22%; and NMB of −29% and − 7% for Code_Saturne and SinG, respectively).

Neighborhood-scale urban form typologies of large metropolitan areas: Observations on Istanbul, Cairo, and Tehran

The micro-level urban morphology of large cities in the Middle East and North Africa and southeastern Europe has not been thoroughly investigated, and its transformation during the past decades has remained less-studied. Hence, this study is meant to partially explain urban morphology of Istanbul, Cairo, and Tehran, three megacities of the region by focusing on the historical neighborhood typologies of the past century. The overall aim of this study is to address the feedbacks of historical urban transformations during the past 100 or 150 years to some important aspects of livability like mobility and social interactions. The objectives are to define the typologies of neighborhoods in the three cities and how they have changed over time, to clarify if the neighborhood-level urban form of the three cities have transformed in a similar fashion, and to address the differences between the cities. The variables of this study were population density, centrality, formation and location of facilities, and configuration of street networks, which were tested by T and Chi-square methods in a representative sample of 259 neighborhoods randomly selected from the case-study cities. The results of statistical hypothesis testing reveal a similarity of neighborhood transformations in the cities in terms of population density. Considerable similarities were found in case of historical changes in centrality (the centeredness of neighborhood amenities), location of neighborhood facilities, and street networks; however, the three cities have general similarities in trends, with potentially similar results for urban mobility. The most important identified planning, political, and societal trends that transformed the neighborhood morphologies were top-down interventions in the 1930s and 1940s, socioeconomic and lifestyle changes in the 1970s because of a jump in oil prices, Iran's 1979 revolution, the Iran-Iraq War for Tehran, internal migration triggered by industrialization, mass and formal housing production for Istanbul, and European inspiration in urban planning in the late 19th century, adoption of socialist ideologies in the 1960s, and the capitalist approach to urban planning in recent years for Cairo.

Measuring the Impact of Street Network Configuration on the Accessibility to People and Walking Attractors

A common approach to evaluating the quality of urban environments in terms of walkability is to measure the accessibility of walking attractors. For this purpose, the information on street network configuration and distribution of walking attractors is required. However, in the early planning stages when not all the necessary data on land use allocation is available, or if the knowledge about the walkability impact of the pure street network configuration is required, this approach is of little use. By addressing this deficiency, we developed method for predicting the accessibility of walking attractors only by using the information on the street network configuration. This method is based on the hypothesis that street network configuration influences how people move through space, and this in turn affects the allocation and accessibility of walking attractors. We empirically test this hypothesis in a case study of Weimar, Germany and found that street network configuration alone was significant and the strongest predictor of AWA. We show how street network influences the distribution of people in terms of pedestrian movement flows and that the access to these movement flows is highly correlated to the neighbourhood walkability. This highlights the importance of urban structure as an interface for social interaction and suggests the positive effect of social proximity on the quality of environment.

Spatial Configuration and Online Attention: A Space Syntax Perspective

The spatial behavior of tourists is an important part of the research on congestion management and sustainable planning of tourism destinations. Combined with user-generated content (UGC) and site-based survey data, this study conducted an overlaying analysis between street network configurations that resulted from space syntax and tourist preferences. Based on space syntax, tourist movement is influenced by the distribution of scenic spots and the structure of tourist trails in scenic mountain areas. The results reveal that the distribution of scenic spots has a significant impact on tourist flow and visitors’ choices of entrance to the mountain; the volume of online sign-ins is highly correlated with landscape attention, axial control values and the local integration value of the trails; and tourists’ attention focuses on the entrance area and the few tourist-sight markers. This study advances the understanding of the spatial patterns of within-destination tourist behavior; this knowledge will be helpful in alleviating congestion in mountain scenic areas and providing effective guidance for tourists to plan an ideal tour route.

Urban Spatial Order: Street Network Orientation, Configuration, and Entropy

Street networks may be planned according to clear organizing principles or they may evolve organically through accretion, but their configurations and orientations help define a city’s spatial logic and order. Measures of entropy reveal a city’s streets’ order and disorder. Past studies have explored individual cases of orientation and entropy, but little is known about broader patterns and trends worldwide. This study examines street network orientation, configuration, and entropy in 100 cities around the world using OpenStreetMap data and OSMnx. It measures the entropy of street bearings in weighted and unweighted network models, along with each city’s typical street segment length, average circuity, average node degree, and the network’s proportions of four-way intersections and dead-ends. It also develops a new indicator of orientation-order that quantifies how a city’s street network follows the geometric ordering logic of a single grid. A cluster analysis is performed to explore similarities and differences among these study sites in multiple dimensions. Significant statistical relationships exist between city orientation-order and other indicators of spatial order, including street circuity and measures of connectedness. On average, US/Canadian study sites are far more grid-like than those elsewhere, exhibiting less entropy and circuity. These indicators, taken in concert, help reveal the extent and nuance of the grid. These methods demonstrate automatic, scalable, reproducible tools to empirically measure and visualize city spatial order, illustrating complex urban transportation system patterns and configurations around the world.

Measuring the effects of street network configurations on walking in Seoul, Korea

Many scholars have confirmed the close correlation between street network configurations and pedestrian behavior. To elaborate on this discussion and to analyze the connection between street layout and walking using sophisticated methods, we attempt to capture the links and surrounding network features of urban street patterns. To this end, we employ the following four elements: closeness, betweenness, severance, and efficiency. Our empirical study examines street network configurations via a multi-scale network radius. The results show that locations with closer destinations and areas where people pass more frequently throughout a given network are associated with higher walking volume. Furthermore, a greater resemblance between straight-line and path distances from origins to destinations tend to encourage walking mobility. A longer convex hull, with a maximum radius that covers a wider shape and structure of links, is the most favorable setting for walking within a radius of up to 500m. We confirm that a higher convex hull-shape index reveals more deviation from the circularity of a street network's convex hull. This negatively affects walking within a radius of 1–2km. We conclude that link and network radius-based attributes of street formations have significant effects on the spatial variations of walking within multi-scale walkable neighborhoods. The framework and results are intended to help with the design of pedestrian-friendly street patterns and to create sustainable and livable cities.

Urban Vitality in Dutch and Chinese New Towns. A comparative study between Almere and Tongzhou

Urban Vitality in Dutch and Chinese New Towns. A comparative study between Almere and Tongzhou

“Form Syntax” as a contribution to geodesign: A morphological tool for urbanity-making in urban design

Creating vibrant urban places is a challenging task in urban design due to the intangible feature of urbanity. This paper presents Form Syntax, a design analytical tool that is capable of assisting urbanity making in design practices based on understandings of three essential urban morphological elements and their influences on urbanity. Using the geographical information system (GIS), Form Syntax integrates three methods—Space Syntax, Spacematrix, and Mixed-Use Index—to measure the street-network configuration, building density, and functional mix, respectively. These three components can be quantified and combined to represent urban morphological features, thereby providing a classification of the degree of urbanity. Form Syntax contributes to geodesign by combining quantitative tools with traditional, intuition-based design to achieve a clear visualisation of the degree of urbanity of a place, which can subsequently be used to propose spatial strategies for enhancing vibrant urban places. The Dutch city of Rotterdam is used to illustrate how the tool improves the traditional site analysis, idea evaluation, and proposal evaluation phases of urban design. A GIS add-in has been developed to enhance the appeal of Form Syntax among urban design practitioners.

Spatial access to pedestrians and retail sales in Seoul, Korea

The retail sector plays a significant role in urban economic development, smart growth policies with mixed land use, and retail desert issues. In addition, urban policies and designs for pedestrian-friendly urban settings have become a dominant paradigm to reshape urban environments. As retail sales depend considerably on the volume of neighborhood pedestrians, the link between pedestrian mobility and retail sales has been a key issue in studies, designs, and economic development of urban areas. Despite the importance of the topic, few empirical studies have examined how pedestrian volumes along street networks affect retail prosperity in urban spaces. Hence, this study investigates the effect of accessibility and centrality to walking volume on retail sales in Seoul by considering pedestrian volumes and street network configuration concurrently. Multilevel regression models confirm that spatial access to pedestrians has differing effects on retail sales according to the type of retail sector. Specifically, a higher accessibility to and visibility of retail stores for walkers tend to improve the sales performance of all retail types. Further, the sales of the Medical Services and Education sectors are remarkably sensitive to the combined effects of pedestrian and street configuration, unlike those of the three other sectors, namely Food, Retail, and Services.