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... combination of the above described areas, flows, and eco-zones lead us to portray the Texas Triangle as shown in Figure 9. It includes 66 counties encompassing 57,430 square miles with a total population of nearly 15 million (Figure 9 and Table ...
Citations
... The definition of the Texas Triangle has invited arguably the most debate in the U.S. megaregion discourse. There are different versions of defining one or more megaregions in or around Texas [25]. Aside from the triangle version proposed by RPA, Lang and Dhavale proposed two corridor megaregions, one following Interstate highway 35 going from San Antonio, Texas to Kansas City, Missouri and the other along the Gulf of Mexico stemming from Brownsville, Texas to Mobile, Alabama [23]. ...
Urban science research and the research on megaregions share a common interest in the system of cities and its implications for world urbanization and sustainability. The two lines of inquiry currently remain largely separate efforts. This study aims to bridge urban science and megaregion research by applying network science’s community detection algorithm to explore the spatial pattern of megaregions in the contiguous United States. A network file was constructed consisting of county centroids as nodes, the direct links between each pair of counties as edges, and inter-county commuting flows as the weight to capture spatial interactions. Analyses were carried out at two levels, one at the national level using Gephi and the other for the State of Texas involving NetworkX, an open-source Python programming package to implement a weighted community detection algorithm. Results show the detected communities largely conforming to the qualitative knowledge on megaregions. Despite a number of limitations, the study indicates the great potential of applying network science analytics to improve understanding of the spatial process of megaregions.
... We follow the definition of the Texas Triangle by Butler et al. [27] and Zhang et al. [28] with minor modifications. Using county as the geographic unit of analysis, megaregion is predominately defined by its economic and transportation connectivity, ecological and cultural similarity [28]. ...
... The eastern region of Texas which is within the humid subtropical climate zone (including Dallas and Houston) has more than 1500 mm of annual precipitation. We follow the definition of the Texas Triangle by Butler et al. [27] and Zhang et al. [28] with minor modifications. Using county as the geographic unit of analysis, megaregion is predominately defined by its economic and transportation connectivity, ecological and cultural similarity [28]. ...
... We follow the definition of the Texas Triangle by Butler et al. [27] and Zhang et al. [28] with minor modifications. Using county as the geographic unit of analysis, megaregion is predominately defined by its economic and transportation connectivity, ecological and cultural similarity [28]. We replaced Delta County with Burnet County, in the original definition in Butler et al. study. ...
As the world becomes increasingly urbanized, it is vital for planners and policy-makers to understand the patterns of urban expansion and the underlying driving forces. This study examines the spatiotemporal patterns of urban expansion in the Texas Triangle megaregion and explores the drivers behind the expansion. The study used data from multiple sources, including land cover and imperviousness data from the National Land Cover Database (NLCD) 2001–2016, transportation data from the Texas Department of Transportation (TxDOT), and ancillary socio-demographic data from the U.S. Census Bureau. We conducted spatial cluster analysis and mixed-effect regression analysis. The results show that: (1) urban expansion in the Texas Triangle between 2001 and 2016 showed a decreasing trend, and 95% of the newly urbanized land was in metropolitan areas, especially at the periphery of the central cities; (2) urban expansion in non-metropolitan areas displayed a scattered pattern, comparing to the clustered form in metro areas; (3) the expansion process in the Texas Triangle exhibited a pattern of increased development compactness and intensity; and (4) population and economic growth played a definitive role in driving the urban expansion in the Texas Triangle while highway density also mattered. These results suggest a megaregion-wide emerging trend deviating from the sprawling development course known in Texas’ urban growth history. The changing trend can be attributed to the pro-sustainability initiatives taken by several anchor cities and metropolitan planning agencies in the Texas Triangle.
... The basis of this study is a travel demand modeling process using TransCAD software. The megaregion's 27 66 counties' come from the regional boundary used by Zhang et al. (2007), and associated network and 28 ...
This paper anticipates the impacts of self-driving or “autonomous” vehicles (AVs), shared AVs, and Atrucks on travel across the Texas Triangle megaregion using year 2040 land use (and network) forecasts. A statewide travel demand model forecasts changes in trip generation, mode and destination choices, and thus vehicle-miles traveled (VMT), congestion, and travel patterns across the megaregion. Results suggest travelers' shifting to more distant destinations, with average person-trip distance rising from 14 to 16 miles. Within-region airline passenger travel is predicted to fall by 82%, as travelers shift to self-driving ground transport options. Without travel demand management (like credit-based congestion pricing and mandated tight headways between AVs), congestion issues will grow, due to an average 47% VMT increase, especially in the region's major cities (Houston, Dallas, San Antonio, and Austin). Automobile travel is anticipated to rise across all distance categories, with increases most evident between suburban and urban zones. Almost 9.6% of link flows will exceed capacity, relative to 4.6% of segments in the no-AV case (for year 2040). Four of the 15 freight industries are predicted to experience an increase of more than 100 million ton-miles per day, due to the introduction of Atrucks, with rising truck trades largely between Houston and other major cities.
... Furthermore, Texas is home to the largest installed capacity of wind power [19], most of the nation's existing hydrogen infrastructure, a unique standalone electricity grid, ERCOT, and one of the nation's most important mega-regions, the Texas Triangle. The Texas Triangle consists of three of the nation's 10 largest cities (Houston, San Antonio, and Dallas), and cities inside the triangle connected by Interstate 45, Interstate 10, and Interstate 35 [20,21]. These features and the mix of vibrant urban centers along with large regions of rural land make Texas a unique case study for understanding a hydrogen supply chain to produce and consume renewable hydrogen. ...
... The Texas Triangle, including Dallas, Houston, and San Antonio, has potential hydrogen demand of over 350 million kg at each point, according to the analysis presented in Fig. 5. Each side of the Texas Triangle has a distance of approximately 300 miles [21], which is a feasible distance of a FCEV [46]. At the same time, Texas has the largest wind capacity installed in the United States [19], and renewable hydrogen can be used for purposes other than transportation, such as refineries [63]. ...
This work developed two methods to investigate the technical and economic potential of hydrogen demand and production: (1) estimating potential hydrogen demand for light-duty vehicles (LDVs) at the county-level using a first-order engineering model, and (2) quantifying temporal renewable hydrogen production from wind energy using a linear programming model. The potential hydrogen demand was primarily evaluated for three geographical regions: (1) the United States, (2) Texas, and (3) the Texas Triangle which is one of the nation's most important mega-regions. The linear programming model compared marginal electricity and hydrogen prices to maximize revenue over the course of a year. The analysis primarily focused on the Electric Reliability Council of Texas (ERCOT), but also included other six U.S. electricity markets for hypothetical analysis. Results show that the potential hydrogen demand for LDVs in the United States, Texas, and the Texas Triangle are 53.3, 5.3, and 3.9 billion kg per year, respectively. Using the electrolyzer system energy efficiency of 75% and the marginal hydrogen price of 1/kg), it is only favorable to produce hydrogen during early morning hours, especially, 1–6 a.m., in ERCOT and other electricity markets except California's market. These results could provide information for decision makers to better understand the holistic feasibility of a hydrogen economy in the United States.
... Ongoing planning efforts for a regional rail system, as promulgated by the Lone Star Rail District and the Greater Austin-San Antonio Corridor Council since the 1990s, propose reusing existing freight lines parallel to IH-35 but have not yet delivered any tangible outcomes or benefi ts beyond feasibility studies and proposed routes. This is attributed largely to a lack of nonroad funds at the state and local level, a lack of county planning authority and a disconnect between land-use and transportation planning (Zhang, Steiner & Butler, 2007). Also, when the cities in question have diffi culty providing dependable bus services, let alone pass funding for inner-city light rail just within their own boundaries, it is not surprising that a more far-reaching public transit scheme would also prove challenging. ...
Part of the Texas Triangle mega-region and the Texas Hill Country, the 64-mile Austin - San Antonio corridor is experiencing rapid growth spurred by a localized tech and industry boom, correlative population growth, and popular acclaim as businesses and individuals alike move to the area at an unprecedented rate. The region is characterized by heavy private automobile dependence and diffuse, unguided residential and commercial development that increasingly threatens to destroy the natural assets that so greatly contribute to its attraction. Based on an initial suitability analysis for areas of potential development along the proposed Lone Star commuter rail line that would connect the region, this research investigates current social-ecological urban design theory and related case studies to inform a proposal to encourage resilient growth patterns along the rail line. A focused study is then undertaken on one such identified site, The South End in San Marcos, and attempts to organize the design of a new, urban district based on social-ecological principles.
... Planning efforts for a regional rail system, as promulgated by the Lone Star Rail District and the Greater Austin-San Antonio Corridor Council, that propose reusing existing freight lines parallel to IH-35 have been ongoing since the 1990s but have not yet delivered any tangible outcomes or benefits beyond feasibility studies and proposed routes. This is attributed largely to a lack of non-road funds at the state and local level, a lack of county planning authority and a disconnect between land-use and transportation planning (Zhang, Steiner & Butler, 2007). Also, when the cities in question have difficulty providing dependable bus services, let alone pass funding for inner-city light rail just within their own boundaries, it is not surprising that a more far-reaching public transit scheme would also prove challenging. ...
The central Texas region, anchored by the cities of Austin and San Antonio, has been experiencing rapid growth over the last ten to twenty years. Although linked by IH-35, a heavily trafficked vehicular corridor, there is little dialogue or concerted planning efforts between the various municipalities that are located along this connecting vein, and as a result, the region has suffered from low-density, sprawling development patterns that perpetuate fossil-fuel dependency and are actively degrading the natural value of the surrounding hill country. Plans for a regional rail system that would connect the study area, Lone Star Rail (LSTAR), lack the appropriate structural support and public momentum for implementation. In order to better understand how future development could help build support and demand for this regional connectivity, land use trends over the last decade between 2001-2011, including where high concentrations of urbanization and natural land loss are occurring, are analyzed using GIS in the eight counties along the IH-35 growth corridor, including Travis, Williamson, Bastrop, Hays, Caldwell, Comal, Guadalupe and Bexar. This mapping then provides the basis for identifying suitable locations for new sustainable TOD urban design and development studies along the proposed LSTAR route that could possibly serve as catalysts for increased endorsement of future regional planning efforts.
... Further, population in the United States will likely increase by 40% by 2050 with the growth concentrated in 8-10 megaregions (Dewar and Epstein, 2007). A megaregion consists of two or more metropolitan areas linked with interdependent environmental systems, a multimodal transportation infrastructure, and complementary economies (Butler et al., 2009;Zhang et al., 2007). Ensuring that cities have an adequate supply of water will become increasingly important as human populations continue to concentrate in these highly urbanized megaregions. ...
... The Texas-Triangle Megaregion (TTMR) is one of the emerging megaregions initially identified by the University of Pennsylvania with the Regional Plan Association and the Lincoln Institute . The region is spatially delineated by the metropolitan areas of Dallas/Fort Worth, Austin, San Antonio, and Houston (Fig. 19.1), with a total land size of approximately 155,000 km 2 (59,900 mi 2 ) encompassing 65 of the 254 counties ( Fig. 19.2) in the state (Butler et al., 2009(Butler et al., , p. 1439Neuman et al., 2010;Zhang et al., 2007). The metro areas of Dallas/Fort Worth, Houston, and San Antonio form the vertices of the TTMR, which measure 701, 531, and 624 km (436, 319, and 388 mi), respectively (Butler et al., 2009). ...
... Fault Zone and Escarpment sharply delineates the Southwest Plateau ecoregion from the prairie lands to the east. This area is characterized by hilly limestone terrain dissected by spring-fed streams of tremendous ecological, recreational, and aesthetic importance (Butler et al., 2009;Zhang et al., 2007). Within the TTMR, elevations range from sea level to 1100 m (3600 ft.) on the Edwards Plateau ( Fig. 19.4). ...
The National Research Council (NRC, 2001, p. 2) defined the Critical Zone as ". the heterogeneous, near surface environment in which complex interactions involving rock, soil, water, air and living organisms regulate the natural habitat and determine availability of life sustaining resources." From this original definition, many, now loosely worded, definitions have been crafted to define the limits of this zone as ranging from the top of the canopy layer down to the bottom of the aquifer, so that the Critical Zone includes all the upper zone of Earth sensu lato. The term Critical Zone, referring to this near-surface and surface zone, was first introduced by Gail Ashley in 1988 to recognize that soil connects the vegetation canopy to the soil; the soil connects to the weathered materials and the weathered materials connect to bedrock, and bedrock provides the connection to the aquifer. In recognition of the importance of this cause-and-effect relationship between previously unconnected spheres, the US National Science Foundation (NSF) established 10 Critical Zone Observatories (CZOs) supported by a national office. This was followed by the establishment of Soil Transformations in European Catchments (SoilTrEC) by the consortium of European Union members. Today there are 64 CZOs spread across the planet but within a narrow range of biophysical environments. The raison d'être of the Critical Zone network is driven by basic principles of science: all the research at each location is focused on asking fundamental integrated biophysical questions and collecting and building long-term data banks from a well-studied environment. In this respect, one of the most important applied aspects of the global CZO network will be the development of reliable data that will lead to enlightened policy and management of the geoscience base of Earth. The name "Critical Zone" has become a fashionable term, but very little, truly integrated work occurs at the CZOs, which we argue will only be possible if it recognized that the real thread that connects all the components of the Critical Zone is water. That said, we think the Critical Zone concept is still a step in the right direction to serve as a unifying principle for the geosciences and an opportunity for truly integrative research of the biophysical environment and the role of humans within that environment.
... At the state level, these geovisualizations exposed major regional migration corridors among Houston, Dallas and Austin in Texas, a slight deviation from the more well-known "transportation triangle" that would have included San Antonio instead of Austin (Zhang et al. 2007) (Figure 4). In addition, it was observed that there were minor migration pathways connecting smaller metropolitan areas, including El Paso, Beaumont, Amarillo, Lubbock and Corpus Christi, to these major hubs. ...
The intent of this research was to augment and facilitate analyses, which gauges the feasibility of web-mined demographics to study
spatio-temporal dynamics of migration. As a case study, we explored the spatio-temporal dynamics of Vietnamese Americans (VA) in
Texas through geovisualization of mined demographic microdata from the World Wide Web. Based on string matching across all
demographic attributes, including full name, address, date of birth, age and phone number, multiple records of the same entity (i.e.
person) over time were resolved and reconciled into a database. Migration trajectories were geovisualized through animated sprites by
connecting the different addresses associated with the same person and segmenting the trajectory into small fragments. Intra-metropolitan
migration patterns appeared at the local scale within many metropolitan areas. At the scale of metropolitan area, varying degrees of
immigration and emigration manifest different types of migration clusters. This paper presents a methodology incorporating GIS methods
and cartographic design to produce geovisualization animation, enabling the cognitive identification of migration patterns at multiple
scales. Identification of spatio-temporal patterns often stimulates further research to better understand the phenomenon and enhance
subsequent modeling.
... Three interstate highways, I-10, I-35, and I-45 link the apexes of the Triangle, providing intercity connections in this megaregion (figure 1). For analysis purposes, an explicit working definition of the Texas Triangle was given by Zhang, Steiner, & Butler (2007) State population projections indicate that, by the year of 2050, the Texas Triangle is expected to grow by more than ten million people (TSDC 2008). Associated with the population growth is inevitable growth in mobility demand, which will impose tremendous pressure on the region's already burdened transportation infrastructure. ...
... Past experience has demonstrated that the choices of transportation technologies and decisions on the locations and alignments of transportation infrastructure strongly influence the direction and magnitude of metropolitan expansions. How the metropolitan expansion is directed through smart transportation decision-making has profound implications in regional consumptions of land, water, energy, and other natural resources and shapes the region's sustainability and quality of life for generations to come (Zhang, et al., 2007). ...
... Source: Zhang, Steiner, and Butler, 2007 ...
