Scholarly Works, Civil and Environmental Engineering

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Fracture Initiation Pressure as a Measure of Cemented Paste Backfill Strength
Frimpong, James A.; Shabab, Basel Ahmad; Pandey, Rohit; Chatterjee, Snehamoy; Walton, Gabriel; Brand, Alexander S. (Springer, 2025-06)
This laboratory-scale study presents the development and validation of a hydraulic fracturing technique to directly measure the tensile strength of cemented paste backfill (CPB), providing an alternative to traditional strength testing methods. Fracture initiation pressure (FIP) was used as the primary measure of CPB strength. Experimental results were compared with traditional benchmark measures such as uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), and critical Mode-I fracture toughness (KIc). Regression analysis of experimental results revealed a strong linear relationship between FIP and these benchmark strength measures, indicating that FIP can be used as a reliable predictor of CPB strength. However, traditional linear elastic failure models did not adequately explain the observed FIP values, as they significantly over-predicted the CPB tensile strength. To address this, the Point Stress (PS) model was applied, which provided a more accurate prediction of tensile strength, especially in cases involving small boreholes. The PS model explained observed effects of borehole size on the material’s response to hydraulic pressurization. This study confirms that hydraulic fracturing, interpreted through the PS model, is an effective method for determining CPB strength and provides a practical alternative measure to conventional testing methods.
Modelling earthquake-triggered landslide runout with the Material Point Method
Alsardi, Abdelrahman; Copana, Julio; Yerro Colom, Alba (2021-10)
Landslides triggered by earthquakes cause devastating consequences to downstream infrastructure. The simulation and prediction of these large-strain events remain challenging. The objectives of this paper are i) to validate the Material Point Method (MPM) framework for the study of coseismic landslides, and ii) to compare the capabilities of MPM with mesh-based methods and simplified Newmark-type methods to simulate post-failure runouts. To achieve these objectives, the MPM framework is presented whereby nodal kinematic boundary condition is employed with a moving mesh. Secondly, the framework is validated with a shaking-table laboratory test of a saturated clay slope. Thirdly, a parametric analysis is conducted using 25 real ground motions on a simple theoretical slope. The MPM results are compared to those obtained with mesh-based methods and three state-of-the-art Newmarktype approaches. It is concluded that mesh-based methods are consistent with MPM predictions for small-strain instabilities associated with low energy ground motions (i.e. Arias intensity lower than 4 m/s). When using ground motions with energy above this threshold, mesh-based methods accumulate significant errors associated with bad geometry. MPM results consistently matched permanent displacements predicted with the Newmark-type methods employed in this analysis.
Connecting landslide basal sliding surface characteristics with post-failure kinematics and impact on rigid structures: An MPM numerical study
Roshan, Aaditaya R.; Yerro Colom, Alba (Elsevier, 2025-06-01)
Understanding the landslide failure mechanism, the deformation process, and ultimately the impact forces generated by landslides on structures is essential for risk assessment. This paper connects these three aspects using the Material Point Method (MPM) and highlights the effect of landslides’ basal failure surface characteristics (i.e., geometry and interface friction) on (a) failure mechanism, (b) post-failure kinematics, and (c) impact force on rigid structures. The geometry of a biplanar landslide is considered, along with different types of slope transitions along the sliding basal surface, from a rotational landslide to a perfect biplanar landslide. A comprehensive parametric study with 310 simulations is performed to analyze the landslide post-failure behavior in terms of the radii of transition, the basal friction angle, the distance to the rigid wall, the roughness of the rigid wall, and the scale of the landslide. The results are presented regarding energy evolution, maximum impact force on the rigid wall, and final runout (in the absence of the wall). Results show that relatively small changes in the slope transition can have relevant impacts on kinematics and impact force. For validation purposes, the maximum impact force resulting from numerical results is compared to the predictions from existing semi-empirical approaches, which compare reasonably well. Finally, different methods to evaluate the impact velocity are evaluated, and the effect of numerical practices in the study of impact forces is also discussed.
United States Water Withdrawals Database
Naseri, Md Yunus; Marston, Landon T. (Nature Portfolio, 2025-12-11)
The United States Water Withdrawals Database (USWWD) provides a standardized compilation of user-level water withdrawal data across 42 US states. USWWD provides time series of water withdrawals at unprecedented spatial and temporal resolutions, encompassing 188,857 unique water users, 353,694 points of diversion and use, and 58,439,412 withdrawal volumes included in 7,524,266 records across various sectors. USWWD integrates diverse state-level data sources, standardizing information on water users, withdrawal locations, volumes, source types, and primary water use categories. The withdrawal data combines both direct measurements and various estimation techniques, reflecting the diverse methods utilized by different state agencies in reporting water usage. USWWD addresses significant gaps in national water use data, enabling researchers to conduct detailed analyses of water withdrawal patterns, trends, and drivers across space, time, and sectors. This granular dataset supports a wide range of applications, including water resource management, planning, and policy development. By providing the most detailed national water use data to date, USWWD facilitates new understanding of how society uses water.
Cracking performance evaluation of BMD surface mixtures with conventional and high RAP contents: insights from accelerated pavement testing program
Tong, Bilin; Habbouche, Jhony; Urbaez Perez, Ernesto; Flintsch, Gerardo W.; Diefenderfer, Stacey D.; Diefenderfer, Brian K.; Amarh, Eugene; Katicha, Samer Wehbe (Taylor & Francis, 2026-12-31)
The Balanced Mix Design (BMD) has emerged as a promising approach for mitigating cracking in high reclaimed asphalt pavement (HRAP) mixtures. This study evaluated the cracking performance of a control asphalt mixture and five BMD-optimized asphalt surface mixtures. The mixtures featured various RAP contents, two binder performance grades, a recycling agent, and a warm mix asphalt additive. The analysis integrated continuous longitudinal strain monitoring from Accelerated Pavement Testing (APT), cracking surveys, and laboratory tests. To quantify APT-measured cracking performance, three primary response phases were identified from the continuous strain monitoring. Residual strain was used to determine the initiation of cracking, and deformation uniformity was employed as a data quality indicator. The findings from strain analysis matched APT cracking surveys. Laboratory tests on field cores confirmed no structural damage for the evaluated mixtures, except for a 60% RAP section. All other BMD mixtures demonstrated better cracking resistance over the control mixture, with HRAP BMD mixtures (>30% RAP) outperforming conventional RAP mixtures (≤30% RAP). Correlation analysis between APT and BMD tests examined and supported the corresponding laboratory test thresholds. This study enhanced insights into pavement performance monitoring and highlighted the efficacy of the BMD concept in optimizing the design of HRAP mixtures.
Integrating Pavement Friction and Macrotexture into a Speed-Dependent Pavement Safety Metric for Safety Performance Modeling
Bazmara, Behrokh; Izeppi, Edgar de León; Katicha, Samer W.; McCarthy, Ross; Flintsch, Gerardo W. (MDPI, 2025-12-20)
The paper proposes a pavement safety index, the estimated available friction at the expected travel speed, FRS(v), to model the composed effect of low-slip speed friction and macrotexture on roadway crashes. This index seems to capture the relative contributions of microtexture and macrotexture across different operating speeds. Speed-dependent available friction at 40, 55, and 70 mph was estimated using the speed-correction procedure in ASTM E1960-07 and integrated into Safety Performance Function (SPF) development. Comparison of the resulting SPF models suggests that FRS values corresponding to typical operating speeds can capture the combined influence of SFN (40) and macrotexture on expected crashes for freeways and rural two-lane, two-way highways. For freeways, the estimated available friction at 70 mph (FRS113) produced the most appropriate SPF, evidenced by the lowest AIC. For rural two-lane, two-way highways, the estimated available friction at 40 mph (FRS65) resulted in the lowest AIC value, consistent with the typical operating speeds on these facilities. In contrast, none of the speed-specific friction estimates produced satisfactory model performance for urban and suburban arterials, likely due to the wide variation in traveling speeds and geometric characteristics on these facilities. The applicability of the proposed metric was demonstrated through the development of illustrative investigatory friction levels based on observed crash data, and the identification of candidate roadway segments for friction improvement interventions, and the estimation of the corresponding return on investment for these interventions.
Flexural Performance of Pre-Cracked UHPC with Varying Fiber Contents and Fiber Types Exposed to Freeze–Thaw Cycles
Banik, Dip; Yadak, Omar; Floyd, Royce (MDPI, 2026-01-01)
Ultra-high-performance concrete (UHPC) is an advanced cementitious composite material with high durability and the strength properties exceeding those of conventional concrete. This paper presents the results of experimental testing assessing the freeze–thaw durability of UHPC specimens with varying fiber types (13 mm straight microfibers and 30 mm hooked-end fibers) and fiber percentages, as well as pre-existing cracks. The performance of all specimens was evaluated by measuring resonant frequency at intervals during testing and residual flexural strength after the completion of 350 freeze–thaw cycles. All specimens showed no degradation of resonant frequency over time. However, the pre-cracked specimens showed an increase in resonant frequency over the course of testing. The uncracked straight fibers specimens exposed to freeze–thaw cycles had the highest flexural strength, but the flexural resistance of the pre-cracked straight fibers specimens increased compared to the control specimens after 350 freeze–thaw cycles. The pre-cracked hooked fiber specimens showed higher first cracking strength and similar ultimate strength to the uncracked specimens after freeze–thaw exposure.
Symbiotic bacteriophages exhibit multiple adaptive strategies in activated sludge flocs and contribute to floc stability
Qi, Huiyuan; Wu, Ruonan; Ye, Mao; Huang, Dan; Wang, Luokai; Liao, Jingqiu; Yu, Pingfeng (Elsevier, 2024-07-15)
Despite the importance of phages for the dynamics and functions of microbial communities, it remains largely unexplored how symbiotic phages adapt in activated sludge systems and influence microbial aggregate stability, which is critical for clarification and reliable performance. Based on 12,127 phage contigs recovered from 12 activated sludge microbiomes, the symbiotic phages exhibited broad host ranges and infected dominant prokaryotes in activated sludge. Moreover, these phage communities exhibited high lysogenicity (49% to 66% lysogenic phages) and harbored diverse auxiliary metabolic genes (AMGs) that could enhance microbial aggregate stability, such as genes coding for lipopolysaccharide, peptidoglycan, and extracellular polysaccharide biosynthesis. Additionally, prokaryotic antiviral systems were widely distributed in dominant prokaryotes, particularly the Restriction-Modification (RM) and CRISPR-Cas systems, which could mitigate potential harmful phage infections. Overall, this study reveals the contemporary beneficial relationship between phages and prokaryotic hosts in activated sludge microbiomes and the potential benefits of symbiotic phages on floc stability.
What's on a prophage: analysis of Salmonella spp. prophages identifies a diverse range of cargo with multiple virulence- and metabolism-associated functions
Yates, Caroline R.; Nguyen, Anthony; Liao, Jingqiu; Cheng, Rachel A. (American Society for Microbiology, 2024-06-25)
The gain of mobile elements, such as prophages, can introduce cargo to the recipient bacterium that could facilitate its persistence in or expansion to a new environment, such as a host. While previous studies have focused on identifying and characterizing the genetic diversity of prophages, analyses characterizing the cargo that prophages carry have not been extensively explored. We characterized prophage regions from 303 Salmonella spp. genomes (representing 254 unique serovars) to assess the distribution of prophages in diverse Salmonella. On average, prophages accounted for 3.7% (0.1%–8.8%) of the total genomic content of each isolate. Prophage regions annotated as Gifsy 1 and Salmon Fels 1 were the most commonly identified intact prophages, suggesting that they are common throughout the Salmonella genus. Among 21,687 total coding sequences (CDSs) from intact prophage regions in subsp. enterica genomes, 7.5% (median; range: 1.1%–47.6%) were categorized as having a function not related to prophage integration or phage structure, some of which could potentially provide a functional attribute to the host Salmonella cell. These predicted functions could be broadly categorized into CDSs involved in: (i) modification of cell surface structures (i.e., glycosyltransferases); (ii) modulation of host responses (e.g., SodC/SodA, SopE, ArtAB, and typhoid toxin); (iii) conferring resistance to heavy metals and antimicrobials; (iv) metabolism of carbohydrates, amino acids, and nucleotides; and (v) DNA replication, repair, and regulation. Overall, our systematic analysis of prophage cargo highlights a broader role for prophage cargo in influencing the metabolic, virulence, and resistance characteristics of Salmonella.
Nanoplastics induce prophage activation and quorum sensing to enhance biofilm mechanical and chemical resilience
Wang, Haibo; Chen, Hui; Ruan, Chujin; Liao, Jingqiu; Schwarz, Cory; Shi, Baoyou; Alvarez, Pedro J. J.; Yu, Pingfeng (Pergamon-Elsevier, 2026-01)
Despite the prevalence of nanoplastics (NPs) in natural and engineered water systems and their association with microbial risks, bacterium-phage interactions have been largely overlooked in the context of biofilm formation. Here, we investigated the effects of positively (PS-NH₂) and negatively (PS-COOH) charged polystyrene nanoplastics (PS-NPs) on dual-species biofilms composed of Escherichia coli (λ+) and Pseudomonas aeruginosa. PS-NPs promoted biofilm formation and stability at environmentally relevant concentrations (e.g., 100–1000 ng/L), with PS-NH₂ exhibiting higher influence. The cellular internalization of PS-NPs increased the reactive oxygen species (ROS) levels by 2.18–2.25 folds, triggered prophage λ activation followed by lysis of E. coli (λ+) after exposure to PS-NPs. Transcriptomic analyses revealed that PS-NPs, especially PS-NH₂, activated the SOS response (2.35–2.63-fold), λ phage replication (2.68–3.97-fold), and interspecies quorum sensing (2.24–5.13-fold), which was verified by the proteomic analyses. Therefore, PS-NPs stimulated protective extracellular polymeric substances (EPS) secretion with eDNA content increased to 325.8–433.8 μg/cm². Enhanced EPS production contributed to improved biofilm mechanical properties (1.46–1.57-fold as measured by atomic force microscopy) and increased resistance to chlorine disinfection. Metagenomic analysis of pipeline biofilm demonstrated that PS-NPs promoted bacterium-phage interactions and enhanced bacterial antiviral defense systems, which stimulated multi-species biofilm formation and enhanced environmental resilience. Overall, our findings provide novel insights into the interplay between nanoplastics and bacterium-phage dynamics, highlighting increased microbial risks associated with waterborne nanoplastics.
Initializing a Public Repository for Hosting Benchmark Datasets to Facilitate Machine Learning Model Development in Food Safety
Qian, Chenhao; Yang, Huan; Acharya, Jayadev; Liao, Jingqiu; Ivanek, Renata; Wiedmann, Martin (Elsevier, 2025-02-26)
While there is clear potential for artificial intelligence (AI) and machine learning (ML) models to help improve food safety, the development and deployment of these models in the food safety domain are by and large lacking. The absence of publicly available databases that host well-curated datasets that can be used to develop and validate AI /ML models represents one likely barrier. Thus, we took three previously published datasets, which we further cleaned and annotated, and made them publicly available in a repository called Cornell Food Safety ML Repository. The selected datasets include (i) presence or absence of Listeria spp. in soil samples collected across the U.S. with paired metadata for soil properties, geolocation, climate, and surrounding land use, (ii) presence or absence of Salmonella and Campylobacter in young chicken carcasses tested in processing facilities with associated meteorological and temporal metadata, and (iii) presence or absence of fecal contamination as well as E. coli concentration in New York watersheds with associated metadata for land use, water attributes, and meteorological factors. These datasets can serve as benchmark datasets for developing ML models. To demonstrate the utility of the repository, we developed customizable scripts as well as LazyPredict (a quick screening method) scripts for training different types of ML models using the shared datasets. While this repository provides an important starting point that will allow for the development and testing of ML models to predict foodborne pathogens contamination in different sources, the inclusion of further datasets is clearly needed to advance this field. This paper thus includes a call to action for the deposit of well-curated datasets that can be used for further development of predictive models in food safety. This paper will also discuss the benefits of such public databases, including the assessment of data-sharing scenarios using existing privacy-preserving techniques.
Hotspots of bacterial pathogen abundance and exposure risk in soils of the contiguous United States
Matthews, Emily A.; Goh, Ying-Xian; Hepp, Shannon L.; Liao, Jingqiu; Calder, Ryan S. D. (American Geophysical Union, 2025-12-11)
Soils are reservoirs of pathogenic bacteria that cause human illness, particularly after mobilizing events such as extreme rain. Land-use patterns (e.g., proximity to agriculture) and soil properties (e.g., moisture) are associated with abundance of individual pathogenic bacteria. However, there are major uncertainties in (a) the importance of local/regional land-use decisions relative to overall natural variability of pathogenicity and (b) the correlations among pathogen abundance, climate-linked physical processes increasing pathogen mobility, and the vulnerability of human receptors. This impairs identification of priority areas for outbreak surveillance, which has traditionally focused on food and water distribution networks, and the development of process-based risk screening models. Here, we analyze a novel data set of 622 soil samples covering 42 of the 48 contiguous United States. We describe (a) the relationship between putative pathogenicity and natural and land-use drivers and (b) how hotspots of putative pathogen abundance intersect with climate-linked hazard of mobilization via fire, floods, wind, and fluvial transport, and the social vulnerability of local human populations. Variability in putative pathogenicity can be partially explained by known drivers, with natural variables having greater explanatory power than land-use variables. Relative abundance of putative pathogens is generally higher in forested ecoregions, notably in the eastern and southeastern United States and in proximity to surface waters. Higher relative abundance of putative pathogens, climate risks promoting pathogen mobility, and a relatively vulnerable rural population intersect in the southeastern United States. Integrated sampling and modeling are needed to monitor and forecast health risks from soilborne pathogens.
Shared space and resource use within a building environment: An indoor geography
Villarreal, Mark; Baird, Timothy D.; Tarazaga, Pablo A.; Kniola, David J.; Pingel, Thomas J.; Sarlo, Rodrigo (Wiley, 2025-03)
Indoor spaces are essential to most humans' lives. Furthermore, in many cases, buildings are shared indoor environments that contain diverse people and resources. Spatial patterns of use are important but under-examined aspects of human-building interactions. This study leverages perspectives from human-environment geography and mechanical engineering to examine spatial patterns of use within a network of shared indoor spaces in an academic building at a research university in the United States. Here we ask: (1) What spaces and resources do building users value? and (2) How are values associated with observed measures of use? We hypothesise that spatial patterns of use follow an ideal free distribution (IFD), a common ecological model of resource use. To test this, we define measures of value and use derived from mixed qualitative (n = 50) and survey-based social data (n = 196) and data from a building-based system of accelerometers. Our analyses provide some support for the IFD hypothesis. We discuss the implications of this finding and potential new avenues for geographic research in shared indoor environments.
Global subsidence of river deltas
Ohenhen, Leonard O.; Shirzaei, Manoochehr; Davis, J. L.; Tiwari, A.; Nicholls, R.; Dasho, O.; Sadhasivam, N.; Seeger, K.; Werth, Susanna; Chadwick, A. J.; Onyike, F.; Lucy, J.; Atkins, C.; Daramola, Samuel; Ankamah, A.; Minderhoud, P. S. J.; Olsemann, J.; Yemele, G. C. (Springer, 2026-01-14)
River deltas sustain dense human populations, major economic centres and vital ecosystems worldwide1,2. Rising sea levels and subsiding land threaten the sustainability of these valuable landscapes with relative sea-level rise and associated flood, land loss and salinization hazards1-3. Despite these risks, vulnerability assessments are impeded by the lack of contemporary, high-resolution, delta-wide subsidence observations4. Here we present spatially variable surface-elevation changes across 40 global deltas using interferometric synthetic aperture radar. Using this dataset, we quantify delta surface-elevation loss and show the prevalence and severity of subsidence in river deltas worldwide. Our analysis of three key anthropogenic drivers of delta elevation changes shows that groundwater storage has the strongest relative influence on vertical land motion in 10 of the 40 deltas. The other deltas are either influenced by multiple drivers or dominated by sediment flux or urban expansion. Furthermore, we find that contemporary subsidence surpasses absolute (geocentric) sea-level rise as the dominant driver of relative sea-level rise for most deltas over the twenty-first century. These findings suggest the need for targeted interventions addressing subsidence as an immediate and localized challenge, in parallel with broader efforts to mitigate and adapt to climate change-driven global sea-level rise.
Climate change projected to impact structural hillslope connectivity at the global scale
Michalek, Alexander T.; Villarini, Gabriele; Husic, Admin (Nature Portfolio, 2023-10-25)
Structural connectivity describes how landscapes facilitate the transfer of matter and plays a critical role in the flux of water, solutes, and sediment across the Earth’s surface. The strength of a landscape’s connectivity is a function of climatic and tectonic processes, but the importance of these drivers is poorly understood, particularly in the context of climate change. Here, we provide global estimates of structural connectivity at the hillslope level and develop a model to describe connectivity accounting for tectonic and climate processes. We find that connectivity is primarily controlled by tectonics, with climate as a second order control. However, we show climate change is projected to alter global-scale connectivity at the end of the century (2070 to 2100) by up to 4% for increasing greenhouse gas emission scenarios. Notably, the Ganges River, the world’s most populated basin, is projected to experience a large increase in connectivity. Conversely, the Amazon River and the Pacific coast of Patagonia are projected to experience the largest decreases in connectivity. Modeling suggests that, as the climate warms, it could lead to increased erosion in source areas, while decreased rainfall may hinder sediment flow downstream, affecting landscape connectivity with implications for human and environmental health.
Advancing the science of headwater streamflow for global water protection
Golden, Heather E.; Christensen, Jay R.; Mcmillan, Hilary K.; Kelleher, Christa A.; Lane, Charles R.; Husic, Admin; Li, Li; Ward, Adam S.; Hammond, John; Seybold, Erin C.; Jaeger, Kristin L.; Zimmer, Margaret; Sando, Roy; Jones, C. Nathan; Segura, Catalina; Mahoney, D. Tyler; Price, Adam N.; Cheng, Frederick (Springer Nature, 2025-01)
The protection of headwater streams faces increasing challenges, exemplified by limited global recognition of headwater contributions to watershed resiliency and a recent US Supreme Court decision limiting federal safeguards. Despite accounting for ~77% of global river networks, the lack of adequate headwaters protections is caused, in part, by limited information on their extent and functions—in particular, their flow regimes, which form the foundation for decision-making regarding their protection. Yet, headwater streamflow is challenging to comprehensively measure and model; it is highly variable and sensitive to changes in land use, management and climate. Modelling headwater streamflow to quantify its cumulative contributions to downstream river networks requires an integrative understanding across local hillslope and channel (that is, watershed) processes. Here we begin to address this challenge by proposing a consistent definition for headwater systems and streams, evaluating how headwater streamflow is characterized and advocating for closing gaps in headwater streamflow data collection, modelling and synthesis.
Ion Clusters Reveal the Sources, Impacts, and Drivers of Freshwater Salinization
Marin, Diver E.; Grant, Stanley B.; Bhide, Shantanu V.; Rippy, Megan A.; Gomez-Velez, Jesus D.; Brent, Robert N.; Kaushal, Sujay S.; Post, Harold; Shelton, Sydney; Misra, Shalini; Hotchkiss, Erin R.; Monofy, Ahmed; Alvi, Dongmei; Schmitz, Bradley; Curtis, Shannon; Davis, Christina C.; Vikesland, Peter J.; Husic, Admin (American Chemical Society, 2025-06-16)
Population growth, land use change, climate change, and natural resource extraction are driving the salinization of freshwater resources worldwide. Reversing these trends will require data-centric approaches that identify salt sources, environmental drivers, and ecosystem responses. In this study, we applied principal component analysis and hierarchical clustering to identify ion covariance patterns, or “ion clusters,” in Broad Run, an urban stream in the Mid-Atlantic United States. These clusters correspond to distinct hydrologic regimes and reveal specific salinization risks: (1) phosphorus pollution mobilized during summer storms (Cluster 1); (2) elevated concentrations of sulfate and bicarbonate during baseflow (Cluster 2), likely reflecting groundwater discharge; and (3) elevated specific conductance and sodium, chloride, and potassium ion concentrations during snowmelt and rain-on-snow events (Cluster 3), driven by deicer and anti-icer wash-off. These ion fingerprints offer a transferable framework for diagnosing salt sources, assessing ecological risk, and identifying management targets. Our findings underscore the need for next-generation stormwater infrastructure and smart growth policies to protect aquatic life in rapidly urbanizing watersheds.
State-of-the-Art Analysis of U.S. Flight Event and Surveillance Data Coverage and Future Research Directions
Hotle, Susan; Titlow, Kyle; Hashemipour, Mehdi; Strocko, Ed (SAGE Publications, 2025-11-24)
The Automatic Dependent Surveillance-Broadcast mandate, along with advances in government and third-party flight tracking systems, has allowed researchers to analyze aspects of aviation operations that were not possible beforehand. The purpose of this study is to provide: 1) a summary of flight event data available to the public, 2) a comparison of application programming interface surveillance data available in the U.S., and 3) an evaluation of flight coverage across the data sources. This analysis considers the FAA’s Aviation System Performance Metrics, the Bureau of Transportation Statistics’ Airline Service Quality Performance System, the Official Airline Guide’s On-Time Performance Flight dataset, the FAA’s System Wide Information Management (SWIM), and the OpenSky Network (OSN). It reports the spatial and market segment (i.e., commercial, general aviation, air cargo) coverage, helping researchers identify the appropriate dataset for their studies. This study found that OSN has worldwide coverage of enroute flights, with limited airport surface movement. FAA’s SWIM contains several surveillance datasets, two enroute (only one includes Alaska and Hawaii), and one airport surface datasets. Combining sources allows one source to overcome a spatial limitation of another to generate a complete trajectory. The flight counts by source are reported with a discussion of their discrepancies, where surveillance sources do not capture all flights from the flight event datasets and vice versa. Therefore, surveillance should be considered supplemental and not a replacement for measuring flight counts. This paper then discusses future research directions, given surveillance availability.
Overconsumption gravely threatens water security in the binational Rio Grande-Bravo basin
Richter, Brian D.; Abdelmohsen, Karem; Dhakal, Sameer; Famiglietti, James S.; Fowler, Kat F.; Green, Henry; Marston, Landon T.; Mekonnen, Mesfin M.; Prunes, Enrique; Rohde, Melissa M.; Ruddell, Benjamin L.; Rushforth, Richard R.; Shahbol, Natalie; Sjöstedt, Eric C.; Sandoval-Solis, Samuel (Springer, 2025-11-20)
The Rio Grande-Bravo basin shared by the United States and Mexico is experiencing a severe water crisis demanding urgent attention. In recent decades, water storage reservoirs, aquifers, and annual streamflow volumes have been substantially depleted, leaving little buffer for continued over-consumption of renewable water supplies. Despite the great scarcity of water and intensifying water shortages in this basin, a full accounting of the river’s consumptive uses and losses has never been undertaken. In this study we assemble detailed water consumption estimates from a broad array of sources to describe how surface and ground water were consumed for both direct uses (agricultural, municipal, commercial, thermoelectric power generation) and indirect uses (reservoir evaporation and riparian evapotranspiration) in each of 14 sub-basins during recent decades. We estimate that only half (48%) of water directly consumed for anthropogenic purposes is supported by renewable replenishment; the other half (52%) has been unsustainable, meaning that it is causing depletion of reservoirs, aquifers, and river flows. The over-consumption of renewable water supplies is primarily due to irrigated agriculture, which accounts for 87% of direct water consumption in the basin. At the same time, water shortages have contributed to the loss of 18% of farmland in the river’s headwaters in Colorado, 36% along the Rio Grande in New Mexico, and 49% in the Pecos River tributary in New Mexico and Texas. Farmland contraction in the US portion of the basin has resulted in lowered irrigation consumption and many cities have been able to reduce their water use as well, but irrigation in the Mexican portion of the basin has increased greatly, causing basin-wide consumption to remain high. This severe water crisis presents an opportunity for envisioning a more secure and sustainable water future for the basin, but a swift transition will be needed to avoid damaging consequences for farms, cities, and ecosystems.
The Rebound Effect of Autonomous Vehicles on Vehicle Miles Traveled: A Synthesis of Drivers, Impacts, and Policy Implications
Ahn, Kyoungho; Rakha, Hesham A.; Wang, Jinghui (MDPI, 2025-11-12)
Autonomous vehicles (AVs), including privately owned self-driving cars and shared autonomous vehicles (SAVs), hold great potential to transform urban mobility by enhancing safety, accessibility, efficiency, and sustainability. However, their widespread deployment also carries the risk of significantly increasing vehicle miles traveled (VMT), a phenomenon known as the rebound effect. This paper examines the VMT rebound effects resulting from AV and SAV deployment, drawing on recent studies and global case insights. We conducted a systematic narrative review of 48 studies published between 2019 and 2025, drawing on academic sources and credible agency reports. We do not conduct a meta analysis. We quantify how different automation levels (SAE Levels 3, 4, 5) impact VMT and identify the primary factors driving VMT growth, namely: reduced perceived travel time cost, induced demand from new user groups, modal shifts away from transit, and empty VMT. Global case studies from North America, Europe, Asia, and the Middle East are reviewed alongside regional policy responses. Quantitative analyses indicate moderate to significant VMT increases under most scenarios—for example, approximately 10 to 20% increases with conditional automation and potentially over 50% with high/full automation, under the circumstances of no effective policy interventions. Meanwhile, aggressive ride-sharing and policy interventions, including road pricing and transit integration, can mitigate or even reverse these increases. The discussion provides a critical assessment of policy strategies such as mileage pricing, SAV incentives, and integrated land-use/transport planning to manage VMT growth. We conclude that without proactive policies, widespread AV adoption is likely to induce a rise in VMT, but that a suite of well-designed measures can steer automated mobility towards sustainable outcomes. These findings help policymakers and planners balance AV benefits with congestion, energy use, and climate goals.

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