Subways and urban growth: evidence from earth

We investigate the relationship between the extent of a city’s subway network, its population and its spatial configuration. To accomplish this investigation, for the 632 largest cities in the world, we construct panel data describing the extent of each of the 138 subway systems in these cities, their population, and measures of centralization calculated from lights at night data. These data indicate that large cities are more likely to have subways, but that subways have an economically insignificant effect on urban population growth. Consistent with economic theory and with other studies of the effects of transportation improvements on cities, our data also indicate that subways cause cities to be more decentralized. For a subset of subway cities we also observe panel data describing subway and bus ridership. We find that a 10% increase in subway extent causes about a 6% increase in subway ridership and has no effect on bus ridership. Consistent with the available literature describing the effect of roads on cities, our results are consistent with subways having a larger effect on the configuration of cities than on their sizes, and with subways having a larger effect on discretionary than commute travel

By the Numbers: Russia’s Terrorists Increasingly Target Transportation

If body count is the terrorists’ goal, then surface transportation provides an attractive target— crowds of strangers in confined environments. While Umarov’s Chechen predecessors carried out spectacular hostage seizures at hospitals, a primary school, and even at a theater in the heart of Moscow, trains, subways, and buses have featured heavily among their targets

Mineta Transportation Institute Says Subways Are Still in Terrorists’ Sights

The FBI arrested a California National Guard reservist on March 17 as he headed for the Canadian border on his way to Syria. Once in Syria, Nicholas Michael Teausant, who is also a student at San Joaquin Delta Community College in Stockton CA, planned to join the Islamic State of Iraq and the Levant (ISIL). Although he had never attended the army’s basic training course and was in the process of being discharged by the National Guard for failing to meet “basic education requirements,” Teausant thought he could teach the Syrian jihadists shooting skills and urban warfare tactic

Scaling in transportation networks

Subway systems span most large cities, and railway networks most countries in the world. These networks are fundamental in the development of countries and their cities, and it is therefore crucial to understand their formation and evolution. However, if the topological properties of these networks are fairly well understood, how they relate to population and socio-economical properties remains an open question. We propose here a general coarse-grained approach, based on a cost-benefit analysis that accounts for the scaling properties of the main quantities characterizing these systems (the number of stations, the total length, and the ridership) with the substrate's population, area and wealth. More precisely, we show that the length, number of stations and ridership of subways and rail networks can be estimated knowing the area, population and wealth of the underlying region. These predictions are in good agreement with data gathered for about $140$ subway systems and more than $50$ railway networks in the world. We also show that train networks and subway systems can be described within the same framework, but with a fundamental difference: while the interstation distance seems to be constant and determined by the typical walking distance for subways, the interstation distance for railways scales with the number of stations.Comment: 8 pages, 6 figures, 1 table. To appear in PLoS On

Micro-Macro Analysis of Complex Networks

Complex systems have attracted considerable interest because of their wide range of applications, and are often studied via a \u201cclassic\u201d approach: study a specific system, find a complex network behind it, and analyze the corresponding properties. This simple methodology has produced a great deal of interesting results, but relies on an often implicit underlying assumption: the level of detail on which the system is observed. However, in many situations, physical or abstract, the level of detail can be one out of many, and might also depend on intrinsic limitations in viewing the data with a different level of abstraction or precision. So, a fundamental question arises: do properties of a network depend on its level of observability, or are they invariant? If there is a dependence, then an apparently correct network modeling could in fact just be a bad approximation of the true behavior of a complex system. In order to answer this question, we propose a novel micro-macro analysis of complex systems that quantitatively describes how the structure of complex networks varies as a function of the detail level. To this extent, we have developed a new telescopic algorithm that abstracts from the local properties of a system and reconstructs the original structure according to a fuzziness level. This way we can study what happens when passing from a fine level of detail (\u201cmicro\u201d) to a different scale level (\u201cmacro\u201d), and analyze the corresponding behavior in this transition, obtaining a deeper spectrum analysis. The obtained results show that many important properties are not universally invariant with respect to the level of detail, but instead strongly depend on the specific level on which a network is observed. Therefore, caution should be taken in every situation where a complex network is considered, if its context allows for different levels of observability

Mobility: a double-edged sword for HSPA networks

This paper presents an empirical study on the performance of mobile High Speed Packet Access (HSPA, a 3.5G cellular standard) networks in Hong Kong via extensive field tests. Our study, from the viewpoint of end users, covers virtually all possible mobile scenarios in urban areas, including subways, trains, off-shore ferries and city buses. We have confirmed that mobility has largely negative impacts on the performance of HSPA networks, as fast-changing wireless environment causes serious service deterioration or even interruption. Meanwhile our field experiment results have shown unexpected new findings and thereby exposed new features of the mobile HSPA networks, which contradict commonly held views. We surprisingly find out that mobility can improve fairness of bandwidth sharing among users and traffic flows. Also the triggering and final results of handoffs in mobile HSPA networks are unpredictable and often inappropriate, thus calling for fast reacting fallover mechanisms. We have conducted in-depth research to furnish detailed analysis and explanations to what we have observed. We conclude that mobility is a double-edged sword for HSPA networks. To the best of our knowledge, this is the first public report on a large scale empirical study on the performance of commercial mobile HSPA networks

Spatiotemporal Analysis of Competition Between Subways and Taxis Based on Multi-Source Data

Excessive competition between taxis and subways has eroded the advantages of public transit systems such as worsening road traffic congestion and environment. This study aims to improve the appeal of subways by a comprehensive understating of competition between taxis and subways. We investigate competitive relationship between these two transportation modes by using empirical multi-source data. First, non-negative matrix factorization (NMF) algorithm is used to discover the spatiotemporal travel patterns of subway-competing taxi users (SCTUs). Second, we propose a new index to quantify the competitiveness of subways based on the actual mode choices results. Then, we reveal the spatiotemporal heterogeneity of competitiveness from perspective of subway network. Taking Beijing, China, for a case study, we extract a week's worth of GPS records on taxi trajectory and smartcard data of subways. Subway-competing taxi trips (SCTTs) account for the largest proportion of the total taxi trips. As a result, three basic patterns are found in SCTTs. Subway station pairs with high and less competition are divided according to competitiveness index. Among low competition station pairs, three spatial structures are observed, including low-competition collinearity corridors, radial communities, and links between paralleled subway lines. Combining the distribution results of travel pattern and competitiveness degree, short-term and long-term planning suggestions are recommended respectively for station pairs with high demand but low competitiveness and those with low demand and low competitiveness. These findings provide useful insights into promoting more effective and sensitive policies to balance the competition and attract more taxi passengers to the subway system

The Metagenomics and Metadesign of the Subways and Urban Biomes (MetaSUB) International Consortium inaugural meeting report.

The Metagenomics and Metadesign of the Subways and Urban Biomes (MetaSUB) International Consortium is a novel, interdisciplinary initiative comprised of experts across many fields, including genomics, data analysis, engineering, public health, and architecture. The ultimate goal of the MetaSUB Consortium is to improve city utilization and planning through the detection, measurement, and design of metagenomics within urban environments. Although continual measures occur for temperature, air pressure, weather, and human activity, including longitudinal, cross-kingdom ecosystem dynamics can alter and improve the design of cities. The MetaSUB Consortium is aiding these efforts by developing and testing metagenomic methods and standards, including optimized methods for sample collection, DNA/RNA isolation, taxa characterization, and data visualization. The data produced by the consortium can aid city planners, public health officials, and architectural designers. In addition, the study will continue to lead to the discovery of new species, global maps of antimicrobial resistance (AMR) markers, and novel biosynthetic gene clusters (BGCs). Finally, we note that engineered metagenomic ecosystems can help enable more responsive, safer, and quantified cities

The Effect of Footbridges and Pedestrian Subways on the Movement System Within the Urban Planning

The footbridges and pedestrian subway are among the material components of the urban fabric, itself considered as one of the three important elements, i.e the public transportation special traffic units and pedestrian movement systems, of the transportation system in any part of the world, which will be discussed later. Any defect at the transportation systems elements would lead to ineffective transportation system with traffic jam and difficulties because of a defect between the surrounding environment and the movement system. Therefore, the present study discusses the effect of the footbridges and pedestrian subways on the movement system within the urban planning, the through the theoretical and  practical side, applied through data collection and interviews with specialists, by asking them some unified questions and distributing questionnaires to everybody who used or didn't use the bridges or subways, within the study area.In order to achieve the study's goals, some international studies and one local case were discussed, whereby the effective application of the pedestrian systems was explored, with applied examples to reach the aspired result. Then an analytical study of the case area, located from AL-Istiklal Street until Jordan University Street, was explored in order to reach conclusions, whereby the study area's footbridges and pedestrian subways situation can be assessed and how they are applied with regard to the location, shape and use. Then some recommendations were suggested by raising the necessity to activate the role of the footbridges and pedestrian subways through the correct application of the pedestrian systems locations and improving the bridges construction and architectural criteria in order to achieve smooth, comfortable and easy pedestrian systems. Keywords: Bridges, subways, urban, planning, movement and traffic systems