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New Data and Methods in Accessibility Analysis
... Other studies have also integrated demographic and statistical data on land-use planning (Vala et al., 2015). Some experiments stand out, such as those referencing information extracted from cell phone geolocation and information emitted by them, thereby monitoring spatial behavior patterns of populations and their daily mobility patterns (García et al., 2013;Kuzma and Nikić, 2015;Salas et al., 2015;Condeço et al., 2018). In other experiments, demographic data have been integrated with information on production activities, studies showing the potential of a Geographic Information System (GIS) for these activities (Bao and She, 2014). ...
Existe una tendencia reciente, aunque ya consolidada, encaminada a la búsqueda de una mayor desagregación territorial de la información. En este contexto, la generación de unidades de observación de dimensiones reducidas y geometría regular ha ido tomando fuerza. Así, en este artículo se muestran los resultados de la utilización de datos de distribución espacial de la población y del espacio construido en un nivel de desagregación territorial de dimensiones reducidas y con una unidad de observación homogénea con una malla regular compuesta por celdas cuadradas de 250m de lado. El objetivo principal es mostrar los resultados y las ventajas que reporta trabajar con una mayor desagregación espacial de la información. El resultado es un conocimiento más exhaustivo del territorio y la posibilidad de estudiar de una forma más precisa los patrones de comportamiento de las distintas variables analizadas.
... Other studies have also integrated demographic and statistical data on land-use planning (Vala et al., 2015). Some experiments stand out, such as those referencing information extracted from cell phone geolocation and information emitted by them, thereby monitoring spatial behavior patterns of populations and their daily mobility patterns (García et al., 2013;Kuzma and Nikić, 2015;Salas et al., 2015;Condeço et al., 2018). In other experiments, demographic data have been integrated with information on production activities, studies showing the potential of a Geographic Information System (GIS) for these activities (Bao and She, 2014). ...
... Así, y hasta la fecha, algunos trabajos analizan la integración de datos sobre salud con información de carácter urbano (Trainor, 2017), como la relativa a empleo (Poelman, 2017), a infraestructuras (Santos, 2013) o a tráfico y movilidad (Piela, 2014). Se pueden destacar también otras experiencias en este ámbito, como la referenciación de la información extraída de la geolocalización de los teléfonos móviles y de la información emitida por estos, que permite monitorizar patrones de comportamiento espacial de la población y en relación con su movilidad cotidiana (Condeço-Melhorado et al., 2018;García et al., 2013;Kuzma & Nikić, 2015;Salas-Olmedo et al., 2015). Otras experiencias se refieren a la integración de la información demográfica y las actividades de economía productiva, como trabajo de investigación que permite mostrar las potencialidades de los sistema de información geográfica (sIG) dentro de estas actividades (Bao & She, 2014). ...
La generación de unidades de observación de dimensiones reducidas y geometría regular tiene cada vez más peso en el análisis espacial. Siguiendo esta línea de trabajo, el Instituto de Estadística y Cartografía de Andalucía elabora, desde hace diez años, información integrada en la malla estadística formada por celdas regulares de 250 x 250 metros según las directrices de Eurostat. En este artículo se muestran los resultados de la utilización de datos de distribución espacial de la población y de la vivienda. Se han realizado análisis de autocorrelación y de correlación espacial para conocer la relación que existe entre la Razón de Mortalidad Estandarizada Suavizada y determinados indicadores socioeconómicos y de algunas características de las viviendas. Se muestran los resultados y las ventajas de trabajar en un nivel de desagregación territorial de dimensiones reducidas y con una unidad de observación homogénea, para obtener así un conocimiento más exhaustivo del territorio.
... Nowadays increasing amounts of high-resolution data on the location of service facilities, road networks and buildings are available in many countries, and significant progress has been made in the construction of spatial databases and GIS technology, which brings convenience for the fine-scale analysis (Condeço-Melhorado et al. 2018;Logan et al. 2017). In this regard, the most commonly used is digital road networks provided by OpenStreetMap, but their quality and completeness are not certain in the developing countries (Logan et al. 2017;Vargas Muñoz et al. 2020); as for remote sensing data, many buildings and trees are located in the urban areas, causing shadows and segmented objects in the road extraction process. ...
In recent years, with the rapid expansion of urban space and the explosion of population within communities in China, fire stations face challenges in providing timely response to potential demands throughout their service coverage. To ensure speedy and equitable provision of fire services, it is essential to evaluate the accessibility of fire stations under the current fire service systems. Traditional accessibility analysis is often based on the aggregated large areal units, such as the census tracks, failing to assess accessibility of individual buildings. In this regard, this study seeks to analyze potential accessibility to urban fire stations at a fine scale, i.e., the building level, and to provide valuable information to assist in strategic planning of fire stations in urban areas and within local communities. Because the detailed intra-community roads are not stored in the official city map database, we propose to use a classic GIS technology, the Delaunay triangulation model, to automatically extract the intra-community roads from building footprints. With these private roads integrated into the existing city roads, a simulated road network is constructed. Then, the Voronoi-based method and buffering method are used to assess accessibility to urban fire stations. Results reveal that the current layout of fire stations in the study area is not sufficient to achieve a complete coverage of potential demands in the stipulated time, and the traditional central areas enjoy better access to fire services compared to the periphery areas. The building-level analyses will not only enable decision-makers to strategically allocate new fire stations in the urban areas, but also help local authorities to enhance fire safety management within the community. The proposed method can also be applied to fine-scale analysis of neighborhood services’
accessibility in other cities.
... ICT technologies, in the form of GPS, smartphones, credit cards, transport smart cards, social media posts, and new mobility service providers, generate a large amount of geo-located data as a valuable input for accessibility analysis. Nevertheless, Condeço-Melhorado et al. (2018) contend that despite big data already being available, its use in accessibility analysis is still in its infancy. In addition, they argue that theory on accessibility might be revisited in the light of the fast dynamics of big data and related micro-behavioural patterns. ...
Our mobility system is changing rapidly. We are at the crossroad of major changes in the way we travel and deliver goods. Research agendas are adapting to this changed environment with new challenges and opportunities. This paper presents a research agenda for the future of transportation research structured along eight cluster topics of the Network on European Communication and Transport Activities Research (NECTAR). The research agenda firstly highlights the growing complexity and need for multi- and interdisciplinary transportation research. Secondly, sustainability needs to be addressed in transportation research in its full meaning, including relationships between policy-making investigations and environmental and equity effects. Thirdly, ICTs and digitalisation, the development of (shared) autonomous vehicles and shared mobility will have profound impacts on economies and spatial interactions all-around the world, and availability of high resolution spatial and transportation data. Digitalisation generates many new research opportunities but also give rise to new concerns about privacy, safety, equity and public health.
To create bicycle-friendly urban environments, policymakers need tools for identifying and mapping the most efficient routes in terms of cycling accessibility. Yet, few studies have empirically investigated cycling accessibility in terms of detours. Using crowdsourced GPS data, this study measures both realized detour ratios (RDRs), describing detours resulting from network constraints and intentional behavior, and behavioral detour ratios (BDRs), describing detours resulting solely from intentional behavior. The study analyzes the measures in narrowly defined grid zones of the Copenhagen region and visual examination shows that zones along radial corridors with good connections toward the city center have the lowest RDRs, while the city center zones have slightly higher BDRs. Furthermore, the study uses regression with spatial autocorrelation to examine factors affecting RDRs and BDRs. Well-equipped zones containing more roads, a lot of dedicated bicycle infrastructure, and cycle superhighways have significantly lower average RDRs. Zones with recreation areas and a high percentage of high-income residents significantly increase the average BDRs. The insights of the study enable policymakers to identify where and how to improve bicycle infrastructure from a detour perspective.
It is a practical need to select suitable medical sites from a large number of medical institutions for patients based on their needs and space-time constraints. Different from the common methods for personalized medical site recommendation, this paper proposed a new method of individual space-time accessibility analysis for the recommendation of medical sites, which considered the quantity of real-time resources of medical institutions, the personalized demands of medical users, and the space-time constraints to medical institutions. Next, this method was applied to select medical institution for urban residents. The proposed individual space-time accessibility analysis method is based on the gravity model, which is appropriately improved to enhance the method's metrizability and comprehensiveness. The method also integrates the time-geography science theory to enhance its practical applicability. Meanwhile, the path impedance factor in the model is interfaced with the AMap API, which enables the model to perform personalized real-time path calculation based on route preference and real traffic conditions. After obtaining data on relevant health care websites and open interface, this paper took Jinan as the research area and set up six scenarios, including two university libraries, two residential areas, and two large transportation stations with different users, different time, and different geographical locations, to test the effectiveness of the method. Results indicate: (1) The individual space-time accessibility analysis method in this paper considers several factors, not only emphasizing the objective constraints of real-time space-time resources, but also highlighting individuals' personalized demands. (2) The individual space-time accessibility analysis method in this paper is able to effectively measure the accessibility between individual medical users and medical sites based on the actual situation, not only adapting to different space-time situations, but also providing guiding strategies for improving the quality of medical travels. (3) By the individual space-time accessibility analysis method in this paper, the suitability of each medical site can be ranked and travel advices in different space-time situations can be made, i.e., the method has high applicability
of recommendation. In addition, our individual space- time accessibility analysis method for medical place recommendation integrates the Location Based Service and medical treatments, bring a new approach to digital medical services, not only providing methodological support for the functional construction of the related wise
information technology of 120, but also having good application prospects.
In recent decades, sustainability has become a guiding principle for developments in urban mobility. The demand for urban mobility derives from diverse needs which are increasingly growing. Satisfying these needs in a sustainable way not only concerns environmental aspects, but also incorporates economic and social dimensions. In this sense, the present article examines social components of sustainable mobility. The objective is to explore the problems and perceptions identified by citizens that prevent socially sustainable access. A situational diagnosis and strategic analysis of problems was carried out, applied with a focus on citizen participation in the Metropolitan Area of Concepcion, Chile. The main result is the identification of problems and barriers that mainly affect pedestrian movement and public transport. Specifically, the most vulnerable people declare a high level of insecurity. This method is a contribution applicable to cities in the global south, for the purpose of evaluating social sustainability in urban mobility.
This paper aims to evaluate the impacts of the economic context on traffic congestion and its consequential effects on private vehicle accessibility. We conduct a long-term analysis of spatiotemporal traffic congestion patterns in Madrid (Spain), comparing two urban realms: the 2008 economic crisis and the following post-crisis situation. We apply Tom-Tom Speed Profiles data to assess daily variations in traffic congestion and their changes between both periods, and Twitter data to capture spatial patterns of the daily pulse of the city. Increased traffic, a by-product of economic recovery, resulted in higher congestion, particularly during peak hours. Nevertheless, these changes are spatially uneven. In the city core, an increase in congestion is relatively temporally homogeneous, while in the peripheral suburban zones, there has been only a marginal increase in travel times. On the other hand, in the urban outskirts, increased traffic congestion is more severe but visibly different between north and south. These differences have strong social connotations: over 40% of the population experienced a dramatic increase in travel times (more than 25%) during peak hours. Moreover, low-income groups are more likely to live in the more affected southern districts, suffering most the negative consequences of increased congestion.
This article investigates the selection of a distance measure in location modeling. While in the empirical literature the choice usually boils down to picking one single measure, this research proposes a flexible approach in which several measures may be used in parallel to capture the surrounding economic landscape. This is intended to acknowledge that interactions between agents may take several forms, occurring through different channels and as such being based on different measures. The methodology is applied to the location choice of establishments in the Paris region, using a mixture of ”mono-distance” hurdle-Poisson models. Seven distance measures are considered: Euclidean distance, the travel times by car (for the peak and off-peak periods) and by public transit, and the corresponding network distances. For all the economic sectors considered, the mixture of hurdle-Poisson models performs significantly better than the “pure” mono-distance models. This corroborates that local spatial spillovers are indeed channeled by different means, hence best represented using several measures. The combination of peak and off-peak road travel times (slightly) outperforms other combinations including the Euclidean distance, supporting the choice of meaningful over more abstract measures in spatial econometric models. The distance measure most likely to capture local spatial spillovers varies depending on the economic sector examined, reflecting differences between sectors in operations and location choice criteria.
Accessibility planning with reference to sustainability and equity principles has been advocated as the best approach to deal with the urban mobility complexity. It has enabled the development of more sustainable and fair policies in relation to access provision. However, despite this paradigm shift, many planning initiatives in practice are still focused on assessing alternatives and proposing solutions, instead of centering on the understanding and assessment of problems as the primary activity of planning. Therefore, in order to contribute for the problem-oriented paradigm in the accessibility planning, this work proposes a strategic assessment methodology for unequal and inequitable distribution problems of accessibility and mobility. This methodology relies on spatial analysis techniques and allows the characterization of accessibility and mobility conditions, as well as the diagnosis of accessibility and mobility problems and their causal relationships. It was applied for the case of Lisbon and the results of the performed assessment allowed an intelligent reading of the problems considered. Specifically, it was found that Lisbon presents an unequal and inequitable distribution of job accessibility and mobility by private car and public transport, and also that job accessibility, along with other transportation, land-use and socioeconomic variables, impact the mobility levels of its citizens.
Spatial systems appear to exhibit often a complex pattern of socio-economic development, in terms of (un)employment, income, mobility, ethnic composition, and urbanisation rates. Their evolution is co-determined by such factors as: market proximity, labour and housing market developments, public amenities, use of and access to transport systems, socio-economic composition of the population, etc. In addition, a sine qua non for sustaining urban economic growth is the local or regional presence of individual and collective cognitive assets that favour knowledge acquisition and transfer, education, innovation, and creativity. In this context, social capital and spatial accessibility are critical factors. The present paper aims to provide an operational framework for mapping out and understanding the mechanisms which drive spatial systems from the perspective of the resilience of urban areas, in the light of their social capital in combination with accessibility. Particular attention is therefore given to the essential role of social capital and transport accessibility in shaping both the economic development of cities and the spatial pattern in the evolution of cities, in terms of, inter alia, education, age, ethnic composition, (un)employment, and socio-economic poverty. For our quantitative analysis of the Swedish urban system, a quantile regression model is introduced and applied in order to study which urban-economic factors in Sweden determine the different levels of social capital, which are seen here as the fundamental component of the resilience capacity of urban areas.
In recent years, the city of Munich has become more crowded due to its strong job market and its popularity as a tourist destination, resulting in a shortage of affordable housing and a strained transport network. It became evident that the city of Munich could not solve these problems alone, and would need close cooperation with neighboring municipalities that considered the various stakeholders. In 2007, this resulted in the formation of the Metropolitan Region of Munich, home to nearly six million people from 27 counties and 6 large cities, and includes 158 participating institutions. In 2009, the TUM Accessibility Atlas was developed for this newly formed region after numerous discussions with a variety of regional stakeholders who described their needs in assessing land-use and transport measures. The major task of this tool was to meet these needs and support this diverse region find a common regional identity.
Investment in transport infrastructure is the main factor responsible for decreasing origin-destination travel times, which are then implemented into a potential accessibility measure. This measure uses population size as a proxy for a destination’s attractiveness. Thus, changes in population distribution as well as the development of the transport infrastructure are mutually responsible for changes in accessibility. The potential accessibility measure is applied to assess change in accessibility in Poland over a twenty year period of time (1995–2015). During this time Poland has experienced a significant change in population distribution. At the same time, accession to the European Union provided an opportunity to use the structural funds and has resulted in an unprecedented development of the transport infrastructure, in particular the road network. The coexistence of both phenomena provides perfect conditions to investigate the complex interrelationship of both components of accessibility, namely transport and land-use. This leads towards a change in the level of accessibility and its spatial pattern, resulting in a transformation of the level of territorial cohesion. However, the selection of the particular impedance parameters greatly influences the importance assigned to an element of infrastructure or a component of population accessibility. Thus, several impedance functions are applied in order to capture their influence on the balance between the infrastructure and population components of accessibility change.
In their national contexts border areas are peripheral and generally located in sparsely populated territories, far from large urban agglomerations. Higher transport costs are therefore incurred by residents and businesses in these areas when connecting with central markets, and this reduces their accessibility to economic activities and more specialized services. Investment in transport infrastructure is a policy instrument used to lessen the remoteness of border regions and increase their accessibility. This study analyses the accessibility of the border regions of Portugal, Spain and France between 1960 and 2010. Accessibility of border regions is compared to national averages and between national and international connections. The market potential and daily accessibility indicators have been selected for this analysis using a joint approach that offers a complementary view of the changes, which occurred over this period. Given their peripheral condition, border regions are generally less accessible than the national average. However, results show that transport investments over this 50-year period helped to improve the accessibility conditions of border regions. Most interesting is the fact that many border regions have increased their accessibility levels at a higher pace than the national average, thereby reducing the accessibility gap with the rest of the country. Border regions suffer from lower accessibility to international destinations partly due to poorer network conditions. However, results show that during this period the greater changes largely benefited international accessibility. Differences between the two selected indicators offer a more complex and richer picture of the evolution of the accessibility of these border regions.
Many authors argue that issues related to interpretability, lack of data availability, and limited applicability in terms of policy analysis have hindered a more widespread use of accessibility indicators. Aiming to address these aspects, this paper presents two accessibility computation approaches applied to Nelson Mandela Bay in South Africa. The first approach, a household-based accessibility indicator, is designed to account for the high diversity both among the South African society and in terms of settlement patterns. Besides OpenStreetMap (OSM) as its main data source, this indicator uses a census and a travel survey to create a synthetic population of the study area. Accessibilities are computed based on people’s daily activity chains. The second approach, an econometric accessibility indicator, relies exclusively on OSM and computes the accessibility of a given location as the weighted sum over the utilities of all opportunities reachable from that location including the costs of overcoming the distance. Neither a synthetic population nor travel information is used. It is found that the econometric indicator, although associated with much lower input data requirements, yields the same quality of insights regarding the identification of areas with low levels of accessibility. It also possesses advantages in terms of interpretability and policy sensitivity. In particular, its exclusive reliance on standardized and freely available input data and its easy portability are a novelty that can support the more widespread application of accessibility measures.
The organization of modern economies is built upon an efficient transport system and an increasing role is played by the logistics sector in overcoming the constraints of time and distance in modern supply chains. While a large body of literature is dedicated to the spatial distribution of firms and firm location choice in general, surprisingly little is still known about the location patterns of logistics firms, and more specifically about the role of accessibility in their location decisions. We use geo-referenced firm level data along with detailed information on transport infrastructure in order to investigate the geography of logistics firms in Spain. We place specific attention to the relationship between logistics firm location, accessibility, and urban structure. Our results show that these firms are located closer to highways and other transport infrastructure compared to other sectors and that the logistics sector is highly urbanized. Yet, they are also locating increasingly in suburban locations and to some extent in extra-urban locations with good accessibility while central cities of urban areas have experienced a declining share of logistics firms.
Accessibility is essentially a dynamic concept. However, most studies on urban accessibility take a static approach, overlooking the fact that accessibility conditions change dramatically throughout the day. Due to their high spatial and temporal resolution, the new data sources (Big Data) offer new possibilities for the study of accessibility. The aim of this paper is to analyse urban accessibility considering its two components –the performance of the transport network and the attractiveness of the destinations– using a dynamic approach using data from TomTom and Twitter respectively. This allows us to obtain profiles that highlight the daily variations in accessibility in the city of Madrid, and identify the influence of congestion and the changes in location of the population. These profiles reveal significant variations according to transport zones. Each transport zone has its own accessibility profile, and thus its own specific problems, which require solutions that are also specific.
Preprint: https://arxiv.org/abs/1610.06450
The interest in disentangling the role of borders in international trade is growing even within
virtually borderless areas like the European Union. While there are a variety of research studies
measuring how borders affect trade, there is little insight into the impact of borders on the
potential accessibility to markets. The aim of this paper is twofold. First we provide a coherent
calibration of the impedance parameters affecting trade (border effect based on best official data
available and with a sound estimation of distance and the distance decay parameter with the use
of network-based measurements). The second objective is to ascertain to what extent the market
potential of different countries is hampered by the border effect. The analysis reveals that
calibrating distance decay and considering border effects provides more realistic results. These
results evidence that peripheral areas are more sensitive to the estimation of the distance decay
parameter, whilst the main metropolitan regions are less affected by both distance decay and
border effects. Finally, we present the decomposed market potential in a spillover-like matrix
showing those countries that have a diversified set of contributors to their market potential and
those where the number of contributors is limited
Purpose Accessibility measurements are good tools for analysing the performance of possible policies on land use / transport / society systems. Until now, accessibility has been approached from a static perspective, even when variations in it depend on short term temporal changes in network function. Solutions based on static measurements, with journey costs taken as units based on free-flow travel time; do not reflect real network performance at different times of the day. Methods In order to broaden our understanding of accessibility and study real-world dynamism in depth, information from new sources has been incorporated into traditional accessibility measurements, with actual observed data on the daily variations in speed profiles. These variations have been used to assess the impact of congestion on accessibility, with dynamic scenarios calculated every 15 min. Results The variations in daily accessibility in the metropolitan areas of Madrid and Barcelona (Spain) have been mapped with reasonable computational costs. Although both cities have a similar global behaviour pattern, each has a different daily spatial accessibility distribution. Madrid appears to be more resilient than Barcelona. Conclusions With new technologies it is possible to overcome previous technical barriers, such as the lack of reliable information or calculating capacity. An ordinary computer has been used to obtain complete and detailed temporal profiles of the two traditional accessibility measurements. Thanks to these new measurements, we have a better understanding of accessibility. However, in order to express a dynamic phenomenon in static format, appropriate mapping schemes would have to be devised.
A growing body of empirical urban economic studies suggests that agglomeration and accessibility externalities are important sources of the uneven distribution of economic activities across cities and regions. At the same time, little is known about the importance of agglomeration economies for the actual location behavior of firms. This is remarkable, since theories that underlie agglomeration economies are microeconomic in nature. In a case study of the Dutch province of South Holland, we analyze micro-level data to determine the extent to which relocation decisions are dependent on accessibility and agglomeration externalities when controlling for firm characteristic. These externalities are measured with location attributes for both own-sector localization and urbanization economies and for proximity to transport infrastructure. The results confirm that firm relocation behavior is affected much more by firm-level attributes (size, age, and growth rate) than by agglomeration and accessibility attributes. Still, accessibility and agglomeration are significantly attached to firm relocations, though their effects vary over sectors. Own-sector and generalized external economies are more important for a firm’s location choices than proximity to transport infrastructure.
The reliability and vulnerability of critical infrastructures have attracted a lot of attention recently. In order to assess these issues quantitatively, operational measures are needed. Such measures can also be used as guidance to road administrations in their prioritisation of maintenance and repair of roads, as well as for avoiding causing unnecessary disturbances in the planning of roadwork. The concepts of link importance and site exposure are introduced. In this paper, several link importance indices and site exposure indices are derived, based on the increase in generalised travel cost when links are closed. These measures are divided into two groups: one reflecting an "equal opportunities perspective", and the other a "social efficiency perspective". The measures are calculated for the road network of northern Sweden. Results are collected in a GIS for visualisation, and are presented per link and municipality. In view of the recent great interest in complex networks, some topological measures of the road network are also presented.
In much accessibility research, arbitrary estimates of the distance sensitivity parameters have been used to represent the distance decay parameters in potential accessibility models. These estimates might be considered arbitrary since the choice of value and the choice of the distance decay function is often motivated by statistical indicators of the goodness of fit on spatial flows, given the fact that measures of ‘real’ accessibilities are missing. Starting from these considerations, in this chapter we introduce a new approach, the half-life model originating from the natural sciences, to estimate distance decay parameters. This method is compared with two conventional approaches originating from spatial economic science for the computation of distance decay parameters: the unconstrained and the doubly constrained spatial interaction models. The emerging distance decay parameters will be then considered in the construction of accessibility indicators based on the potential accessibility introduced by Hansen in 1959. In this context, both the mean and the median distance will be taken into account in order to identify MAUP-related issues. The exploration of these three approaches focuses on empirical analyses of accessibility in Sweden at the municipal level for 1993 and 2008. All the emerging accessibility indicators are compared in order to analyse similarities and differences in the hierarchical accessibility levels of the Swedish municipalities. The chapter concludes with some methodological and empirical remarks on the adoption of these three approaches, in the light of possible forecasts and related policy analyses.
Using a geo-coded micro-level panel dataset for Spanish manufacturing firms, I estimate the effect of access to highways on firm-level productivity. To identify the causal effect of highways, I have relied on different fixed-effects specifications, instrumental variables and controls for geography, geology and history. Since highways also attract economic activity, leading to local density increases, which in turn could affect productivity through agglomeration benefits, I also present estimations that control for local employment densities. The results show that highways raise firm-level productivity directly and beyond the effect of density. Additional results show that highway benefits are unevenly distributed across sectors and space.
Accessibility to jobs by transit is increasingly incorporated into transportation and land-use planning objectives, as it is proven to be a relevant indicator for assessing land-use and transport performance. With a rise in time-sensitive accessibility measures, choosing the appropriate measure is increasingly challenging for engineers, planners and policy-makers. This research presents a comparative analysis of three accessibility measures, two of which are time-sensitive. Relative accessibility measures are generated for five time periods based on a) constant transit service and number of jobs (constant); b) variable transit service and constant number of jobs (static) and c) variable transit service and variable number of jobs available (dynamic). The measures are first assessed by incorporating them into a transit mode share model. Interestingly, findings show that all three measures behaved similarly in the three regression models. Furthermore, all accessibility measures are found to be highly correlated. The study suggests that the most commonly used accessibility measure (constant measure at 8 am) is representative of the relative accessibility (static or dynamic) over the course of the day and is thus appropriate and meaningful to be used by policy-makers, engineers and planners.
Álvarez-Ayuso I. C., Condeço-Melhorado A. M., Gutiérrez J. and Zofío J. L. Integrating network analysis with the production function approach to study the spillover effects of transport infrastructure, Regional Studies. The production function approach is used to analyse the role of transport infrastructure on regional gross domestic product (GDP) using new definitions and measures of road network capital stock that represent the real benefit obtained by regions when accessing markets. Improving the existing methodologies, the infrastructure stock is weighted with trade data so as to estimate the direct effects on production of a region's own infrastructure (what is termed here ‘internal stock’), as well as the spillover effects that it receives from using that of neighbouring regions (imported stock). The methodology is illustrated by using Spanish data for the 1980-2007 period and these internal and imported infrastructure stocks are calculated using geographical information system (GIS) network analysis based on generalized transportations costs. With this new data set, successive regressions are performed controlling for endogeneity and the obtained results are compared with those of previous research. The validity of this methodology and the existence of significant and rather large spillover effects that even outweigh the effect of the internally endowed capital stock on aggregate production are confirmed. On average, the relative magnitude of the spillover effects to that of the internal (own) stock effect increases with the level of territorial disaggregation, i.e., it is larger for provincial data than for regional data. Unfortunately, it is also found that spillover effects are asymmetric, exhibiting negative values for poorer regions, as they do not profit from the capital stock existing in their neighbouring areas as do their richer counterparts, thereby casting doubts on the cohesion effects attributed to transport infrastructure investments.
The recent enormous interdisciplinary interest in network concepts, analysis, and modelling – arising from the study of complex interconnected dynamic systems – underlines the simplicity of laws describing these phenomena. Networks often show common behaviour, based on their topological characteristics, and this connectivity behaviour is mainly modelled by exponential/power form distributions. In other words, the topological properties of a network can give useful insights into: how the network is structured; which are the most 'important' nodes/agents; and how network topology can influence the patterns emerging from the conventional spatial economic laws (such as equilibrium theory, spatial interaction theory, etc.). This topology structure is expressed by very simple laws, and in most cases these laws can be interpreted in a spatial economic framework. In this framework, it is still an open research issue which specific and novel contributions network analysis can offer to spatial economic analysis, and – vice versa – whether the solidity of spatial economic laws needs to be reconhandred in the light of recent advances in complexity and network theory. Hence, a dual analysis is necessary, in order to explore potential connections between these two approaches (spatial economics and network analysis). In this context, the accessibility indicator – although expressed in a very simple form – can play a strategic role, since it may detect the most connected network centres (hubs), as well as trace their development and decline. This paper is devoted, first, to a methodological analysis, by exploring the interrelationships between theories and models in spatial economics and network analysis. This interdisciplinary synthesis calls for further reflections on network complexity and the simplicity of the associated models and indicators – such as accessibility. A further issue worth to be explored is the connection between accessibility and resilience. The question is whether the accessibility indicator can be related to the identification of resilience/fragility in connectivity network structures. Current policy strategies which focus on resilience show the relevance of this issue and the need for continuing research on the links between complex transport networks, accessibility and resilience, mostly by exploring this relationship at different scale levels and its impact on the whole network.
This paper considers the development of a method for network vulnerability analysis which considers the socio-economic impacts of network degradation and seeks to determine the most critical locations in the network. The method compares the levels of remoteness (or its inverse, accessibility) of localities within the study region, on the basis of the impacts of degradation of the road network on a recognised accessibility/remoteness index that can be applied to each and every location within the region. It thus extends the earlier work on accessibility-based vulnerability analysis which was limited to assessment of impacts on selected nodes in a network. The new method allows study of impacts on both specified locations (which do not have to be represented as network nodes) and the region as a whole. The accessibility/remoteness index is defined so that an accessibility surface can be calculated for the region, and the volume under this surface provides an overall measure of accessibility. Changes in the volume under different network states thus reflect the overall impacts. The method is applied to a rural region in south east Australia.
A review of accessibility measures is presented for assessing the usability of these measures in evaluations of land-use and transport strategies and developments. Accessibility measures are reviewed using a broad range of relevant criteria, including theoretical basis, interpretability and communicability, and data requirements of the measures. Accessibility impacts of land-use and transport strategies are often evaluated using accessibility measures, which researchers and policy makers can easily operationalise and interpret, such as travelling speed, but which generally do not satisfy theoretical criteria. More complex and disaggregated accessibility measures, however, increase complexity and the effort for calculations and the difficulty of interpretation. The current practice can be much improved by operationalising more advanced location-based and utility-based accessibility measures that are still relatively easy to interpret for researchers and policy makers, and can be computed with state-of-the-practice data and/or land-use and transport models. Research directions towards theoretically more advanced accessibility measures point towards the inclusion of individual's spatial–temporal constraints and feedback mechanisms between accessibility, land-use and travel behaviour. Furthermore, there is a need for theoretical and empirical research on relationships between accessibility, option values and non-user benefits, and the measurement of different components of accessibility.
This paper proposes a methodology to measure spatial spillovers of transport infrastructure investment and to monetize them by distributing the costs of the infrastructures envisaged according to the regional distribution of the potential accessibility benefits. We use a transport master plan (the Spanish “Plan Estratégico de Infraestructuras y Transporte” 2005–2020, PEIT) as a case study for applying our methodology. In order to calculate and map regional spillovers, economic potential values are computed using network routines in a Geographic Information System (GIS) by comparing two scenarios: firstly, the scenario PEIT 2020; and secondly the scenario which includes the improvements envisaged for the year 2020 in all the regions except the region whose spillover effects are being analyzed. The differences between these two scenarios represent the potential spatial spillover effects of this region on the rest of the regions. This procedure is repeated for each of the Spanish regions in order to calculate a matrix of inter-regional spillovers in economic potential units. In a second step, this matrix is monetized by distributing the costs of the investment in infrastructures envisaged in the region according to the regional distribution of the economic potential benefits. This inter-regional matrix of investments flows characterizes the “inner”, “export”, and “import” values of each of the regional road investments. Subtracting from the direct investment the exports to other regions and adding the imports from other regions, an estimation of the real investment of the plan in each region taking into account all the spillover effects is obtained. This value can be compared with the direct investment in the region, analyzing whether one region has more or less direct investment than real. The proposed methodology makes it transparent which regions benefit more from national transport investment irrespective of where the investment occurs. The spillover matrix can be a valid instrument, especially in federal states or in the case of transnational projects, in the field of regional economics because it offers very useful information for both planners and policy makers.