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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Path planning of the unmanned surface vehicle in island and reef environments with time-varying vortices</title>
      <link>https://trid.trb.org/View/2660841</link>
      <description><![CDATA[Island and reef environments pose significant challenges for the unmanned surface vehicle (USV) due to dense coral formations and unpredictable eddies. Such conditions frequently cause heading deviations and elevate collision risks. To enhance navigation safety and efficiency in these challenging environments, we improved the implicit quantile network (IQN) algorithm and introduced the risk-reward balance implicit quantile network (RRB-IQN). This approach calculates a risk coefficient based on the number and distance of obstacles within the USV’s perception range. It adjusts the risk preference in the value distribution, allowing the USV to balance reward maximization and risk minimization. Additionally, we developed a dynamic composite reward function to optimize the USV’s navigation efficiency, even under environmental disturbances. The proposed algorithm was tested in simulated environments designed to mimic typical coral reef features. Results indicate that state-of-the-art algorithms, including standard IQN and other baseline methods, often enter vortex cores or pass through narrow gaps. In contrast, RRB-IQN produces faster, shorter, and safer paths. Moreover, it exhibits robust performance in island and reef environments with time-varying vortices.]]></description>
      <pubDate>Thu, 23 Apr 2026 09:12:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2660841</guid>
    </item>
    <item>
      <title>New methods for the scour protection around the pile foundation based on oyster reef cover</title>
      <link>https://trid.trb.org/View/2641361</link>
      <description><![CDATA[Offshore wind turbines usually suffer from severe local scour and environmental challenges. Two novel eco-friendly technologies—oyster reef cover (ORC) and grouting overlaying oyster reef cover (GORC) were proposed as scour countermeasures. In this paper, a series of current scour tests were carried out under the protection of ORC, GORC, riprap, and sacrificial piles. The experimental observations indicated that ORC and GORC could significantly reduce the scour depth. The protection efficiency of ORC and GORC significantly surpasses that of riprap and sacrificial piles. The protection efficiency of ORC is proportional to its extent. When thickness increases, the protection efficiency increases and then decreases. An equation to calculate the protection efficiency of ORC was proposed. The optimal protection parameters were given as Worc/D=7 and torc/h=0.187, which can reduce 98.8 % of the scour depth. Mechanistically, the ORC weakens the underflow and horseshoe vortex, while the slurry enhances the seabed scour resistance. Consequently, the GORC can reduce 99.8 % of the scour depth. The GORC showed superior stability compared to ORC, surpassing riprap. The ecological value and economic advantages of ORC and GORC were discussed. The present work provides a reference for the design of scour protection systems that integrate wind power development, ecological restoration, and marine pasture management.]]></description>
      <pubDate>Fri, 20 Mar 2026 14:47:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2641361</guid>
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    <item>
      <title>Experimental study on wave attenuation and low-velocity wake generation by orifice-type flow-focusing artificial reef arrays</title>
      <link>https://trid.trb.org/View/2660656</link>
      <description><![CDATA[This study utilizes a combined experimental and numerical modeling method to examine how the opening ratio of individual orifice-type flow-focusing reefs and the relative spacing (d/D) within reef arrays affect the mechanisms of wave dissipation and current weakening. The results indicate that reefs with moderately small opening ratios exhibit improved comprehensive performance, achieving higher wave dissipation rates while facilitating the formation of extensive and stable low-velocity zones behind the structures. An optimal relative spacing for wave dissipation exists within reef arrays. When d/D < 1, excessive flow resistance generates strong vortices that diminish the dissipation effectiveness. Conversely, when d/D ≥ 3, the synergistic interactions within the reef array are weakened, reducing their combined wave-dissipating effect. Reef arrays satisfying the Bragg resonant reflection condition demonstrate a substantial increase in wave reflection capacity. However, wave attenuation is not primarily governed by reflection, which contributes only a minor portion. Furthermore, an empirical formula for the transmission coefficient, incorporating the effect of spacing, is proposed, demonstrating robustness in predictive capability. These findings support optimized artificial reef design.]]></description>
      <pubDate>Wed, 11 Feb 2026 15:10:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2660656</guid>
    </item>
    <item>
      <title>Structural optimization of artificial reef based on hydrodynamic and shear stress analyses</title>
      <link>https://trid.trb.org/View/2627078</link>
      <description><![CDATA[The hydrodynamic behavior and scour resistance of artificial reefs are critically influenced by the configuration of structural openings. This study investigates the effects of opening size, shape, and spatial arrangement on flow field performance and bottom shear stress, utilizing both numerical simulations and flume experiments. A validated computational fluid dynamics model was constructed using particle image velocimetry data, and an orthogonal experimental design was employed to analyze the impact of multiple design variables. Key evaluation metrics included relative and efficiency indices for upwelling and wake regions, as well as both maximum and average shear stress values. The results indicate that openings positioned in the upper-middle region markedly improve flow mobility, with an optimal opening ratio of 0.1 achieving superior hydrodynamic performance. In contrast, the size of lower openings exerts a dominant influence on shear stress and scour potential, with a recommended opening ratio of 0.5 for effectively mitigating sediment disturbance. This study provides a practical optimization framework for artificial reef opening design, contributing to the development of structurally stable and ecologically functional artificial reef systems.]]></description>
      <pubDate>Mon, 26 Jan 2026 14:44:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2627078</guid>
    </item>
    <item>
      <title>Influence of longitudinal and lateral spacing of cubic artificial reefs on flow dynamics and scour volume</title>
      <link>https://trid.trb.org/View/2627054</link>
      <description><![CDATA[The spatial configuration of artificial reefs (ARs) critically influences local hydrodynamics, yet systematic assessments of scour stability and deployment efficiency remain limited. Combining flume experiments and OpenFOAM simulations, this study examines how normalized longitudinal (T/D) and lateral (P/D) spacings affect flow interactions, scour processes, and ecological flow features. Here, T and P denote the longitudinal and lateral spacing between ARs, respectively, and D is the AR edge length. Results show that longitudinal spacing transitions from pronounced flow shielding (T/D ≤ 0.5) to peak wake vortex interactions (T/D = 1.0–2.0) and finally independent wakes (T/D > 2.0), directly impacting scour intensity, turbulence, and beneficial ecological flow features like upwelling. Similarly, lateral spacing shifts from merged wakes (P/D = 0) to enhanced gap flows (P/D = 0.5–1.0) and decoupled patterns (P/D ≥ 1.5). A comprehensive evaluation index (Ib) balances ecological benefits, scour stability, and deployment costs, identifying optimal spacings (T/D = 1.0–1.5, and P/D = 1.5–2.0) across multiple weighting scenarios, validated via Monte Carlo simulations. These findings deepen our fundamental understanding of hydrodynamic-scour interactions and offer theoretical foundations and practical guidelines for sustainable marine ranching and the optimal design of offshore ecological infrastructure worldwide.]]></description>
      <pubDate>Mon, 26 Jan 2026 14:44:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2627054</guid>
    </item>
    <item>
      <title>Boater’s Preference for Coral Reef Restoration and Sustainable Resource Management in Florida</title>
      <link>https://trid.trb.org/View/2437862</link>
      <description><![CDATA[The Florida Reef is under intense pressure from excessive human disturbance and climate change. A group of Florida residents including boaters and fishers was surveyed about their concerns and willingness to pay (WTP) for restorative services. A discrete choice valuation experiment was conducted, involving nearly 1,300 respondents, to estimate WTP for coral reef restoration, wide beaches, and clean water. The boaters demonstrated a somewhat higher WTP for a more extensive beach size and coral restoration. The analysis allowed quantification of maritime transportation passengers’ preferences for sustainable resource management. The findings provide useful insights for maritime transportation and coastal management agencies wishing to finance conservation initiatives. Furthermore, the study offers valuable methodological contributions and policy relevant information to incorporate ecosystem service valuations into the decision-making process beyond the study areas.]]></description>
      <pubDate>Tue, 08 Oct 2024 16:31:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2437862</guid>
    </item>
    <item>
      <title>Decision-Making Support System for Vessel Automatic Anti-Grounding and Anti-Reef</title>
      <link>https://trid.trb.org/View/2282920</link>
      <description><![CDATA[Using Electronic Chart Display and Information System (ECDIS) as an effective and reliable information source of static targets and inter-medium for realizing the organic combination of dynamic and static information for vessel's anti-collision, this paper carried out the study on Decision-making Support System for Vessel Automatic Anti-grounding and Anti-reef (DSSVAAA for short). A rectangular area model was suggested for searching the information of dangerous static obstructions, and an algorithm for DSSVAAA was illustrated. Mathematical models for Determining Threshold of Dangerous Water Depth (DTDWD) and parameters of the searching rectangle area were provided in detail.]]></description>
      <pubDate>Fri, 20 Sep 2024 16:24:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2282920</guid>
    </item>
    <item>
      <title>Inferences on Sediment Production and Transport at Carbonate Beaches Using Larger Foraminifera</title>
      <link>https://trid.trb.org/View/2153433</link>
      <description><![CDATA[In the tropical Central and West Pacific as well as in the East Indian Ocean the symbiont-bearing benthic foraminifera (single celled marine organisms getting size of a few millimeters) are the main producers of calcium-carbonate grains deposited at carbonate beaches. The proportion of larger foraminifera tests on sand grains ranges from 20 to 95 %. This amount depends on the two factors productivity and transport, since the larger foraminifers do not live on or in the sandy bottom near the beaches, but prefer firm substrate in high-energy environments close to the front of coral reefs. Therefore, foraminiferal tests are produced in extreme numbers on the reef crest that is covered by filamentous macroalgae or in the transition zone between the crest and the reef moat. After the release of the test by reproduction or death, empty tests are entrained through the high water energy acting at the reef crest and transported. This transport depends on the direction and intensity of currents connecting the production area (reef crest and transition to the moat) with the deposition area (central moat, lagoon, beach). Devastation of the production area and/or the interruption or diversion of water flow hinders the accumulation of larger foraminifera tests at the beach. Understanding the ecology of larger foraminifera in combination with the transport of empty tests is thus necessary to preserve the equilibrium between deposition and removal of sand at carbonate beaches.]]></description>
      <pubDate>Tue, 25 Apr 2023 16:33:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2153433</guid>
    </item>
    <item>
      <title>Setting sustainable limits on anchoring to improve the resilience of coral reefs</title>
      <link>https://trid.trb.org/View/2138415</link>
      <description><![CDATA[Boat anchoring is common at coral reefs that have high economic or social value, but anchoring has received relatively little attention in reef resilience studies. The authors developed an individual-based model of coral populations and simulated the effects of anchor damage over time. The model allowed the authors to estimate the carrying capacity of anchoring for four different coral assemblages and different starting levels of coral cover. The carrying capacity of small to medium-sized recreational vessels across these four assemblages was between 0 and 3.1 anchor strikes ha−¹ day−¹. In a case study of two Great Barrier Reef archipelagos, the authors modelled the benefits of anchoring mitigation under bleaching regimes expected for four climate scenarios. The partial mitigation of even a very mild anchoring incidence (1.17 strikes ha−¹ day−¹) resulted in median coral gains of 2.6–7.7 % absolute cover under RCP2.6, though benefits varied temporally and depended on the Atmosphere-Ocean General Circulation Model used.]]></description>
      <pubDate>Fri, 21 Apr 2023 13:35:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2138415</guid>
    </item>
    <item>
      <title>GIS-based spatial suitability assessment for pacific oyster Crassostrea gigas reef restoration: A case study of Laizhou Bay, China</title>
      <link>https://trid.trb.org/View/2123580</link>
      <description><![CDATA[The oyster reef restoration has raised concerns worldwide due to the advantage of alleviating eutrophication and other ecosystem services. The necessary prerequisite for oyster restoration is identifying suitable sites. A restoration suitability index model for C. gigas reefs was built by combining the Monte Carlo simulation, analytic hierarchy process, hydrodynamic modelling and geographic information systems and applied in Laizhou Bay (LZB), China. The model outputs and sensitivity analysis showed that the east coastal area, the southern part, and the western part of LZB were restoration sites with the maximum suitability, accounting for 15.3 % of LZB. The middle and northern parts of LZB were unsuitable sites restricted by water depth and flow velocity. Ship waterways and marine industries were the major factors causing degradation of the historically recorded oyster reefs. This model can support oyster restoration planning, and can be applied to other oyster species with adjusted indicator system.]]></description>
      <pubDate>Thu, 06 Apr 2023 11:46:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2123580</guid>
    </item>
    <item>
      <title>Anchor scour from shipping and the defaunation of rocky reefs: A quantitative assessment</title>
      <link>https://trid.trb.org/View/2088881</link>
      <description><![CDATA[Anchor scour from shipping is increasingly recognised as a global threat to benthic marine biodiversity, yet no replicated ecological assessment exists for any seabed community. Without quantification of impacts to biota, there is substantial uncertainty for maritime stakeholders and managers of the marine estate on how these impacts can be managed or minimised. This study focuses on a region in SE Australia with a high proportion of mesophotic reef (>30 m), where ships anchor while waiting to enter nearby ports. Temperate mesophotic rocky reefs are unique, providing a platform for a diversity of biota, including sponges, ahermatypic corals and other sessile invertebrates. They are rich in biodiversity, provide essential food resources, habitat refugia and ecosystem services for a range of economically, as well as ecologically important taxa. The authors examined seven representative taxa from four phyla (porifera, cnidaria, bryozoan, hydrozoa) across anchored and ‘anchor-free’ sites to determine which biota and which of their morphologies were most at risk. Using stereo-imagery, they assessed the richness of animal forest biota, morphology, size, and relative abundance. Their analysis revealed striking impacts to animal forests exposed to anchoring with between three and four-fold declines in morphotype richness and relative abundance. Marked compositional shifts, relative to those reefs that were anchor-free, were also apparent. Six of the seven taxonomic groups, most notably sponge morphotypes, exhibited strong negative responses to anchoring, while one morphotype, soft bryozoans, showed no difference between treatments. These findings confirm that anchoring on reefs leads to the substantial removal of biota, with marked reductions of biodiversity and requires urgent management. The exclusion of areas of high biological value from anchorages is an important first step towards ameliorating impacts and promoting the recovery of biodiversity.]]></description>
      <pubDate>Tue, 24 Jan 2023 09:30:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2088881</guid>
    </item>
    <item>
      <title>Combining revealed and stated preference models for artificial reef siting: A study in the Florida Keys</title>
      <link>https://trid.trb.org/View/2053422</link>
      <description><![CDATA[This paper investigates divers’ preferences for artificial reef diving and willingness to pay (WTP) for large ship, artificial reef site attributes in the Florida Keys. The authors investigate diver demand for existing decommissioned ships that have been sunk off the Florida Keys as well as demand for four new vessels that are available for disposal from the U.S. Department of Transportation Maritime Administration inventory. Using survey data from divers, the authors compare revealed preference (RP) site choices, stated preference (SP) choices from a discrete choice experiment, and joint RP/SP choices. The authors' analysis also incorporates stated attribute non-attendance (ANA) at the choice-task level. The authors' results indicate that the joint RP/SP models with stated ANA are preferred, leading to decreases in marginal WTP as well as decreases in the variability of marginal WTP estimates in the 95% confidence intervals. Results provide a framework for directing more efficient future decision making regarding sinkings at locations that will enhance welfare for divers.]]></description>
      <pubDate>Mon, 21 Nov 2022 16:21:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2053422</guid>
    </item>
    <item>
      <title>Shipwrecks are not the ultimate attracting features in a natural marine environment-the case of Karaburun, Turkey</title>
      <link>https://trid.trb.org/View/1948460</link>
      <description><![CDATA[Shipwrecks attract divers. Therefore, decommissioned marine vehicles are used as artificial reefs for recreational diving tourism around the world. The authors examined divers' attitudes towards shipwrecks and their function as an ecological enhancers. The study was carried out in the Karaburun Peninsula, Turkey, where two passenger ships were sunk as artificial wreck reefs to attract diving tourism. Using a questionnaire survey accompanied by face-to-face interviews, of both certified divers and non-certified discovery divers the authors collected information about divers reefs preferences, perception of artificial reefs as well as their socio-demographic characteristics, dive experiences etc. Differences in divers’ wreck (historical or artificial) and reef preferences (natural reefs or artificial wrecks) were analyzed with the Mann-Whitney U test. Overall, divers held the position that artificial wreck reefs provide ecological benefits on fish diversity and stocks (p < 0.05), and experienced divers supported this position more that novice ones. However, experience and number of annual dives did not affect this notion. Non-certified respondents were mostly neutral towards the ecologic and management statements. However, the majority of divers (84%) preferred to dive on natural reefs rather than on shipwrecks. Similarly, most of them (83%) preferred diving to historical shipwrecks which sank in wars or accidents, and not on ships intentionally sunk as attractions. These findings, which are in line with previous literature, put a question mark on the growing practice of sinking nearly any ship to create diving attractions.]]></description>
      <pubDate>Wed, 25 May 2022 09:35:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1948460</guid>
    </item>
    <item>
      <title>Investigating the Efficacy of Natural and Nature-based Features to Increase the Service Life of Coastal Roadways</title>
      <link>https://trid.trb.org/View/1948616</link>
      <description><![CDATA[Seven of the top ten costliest U.S. natural disasters are coastal events, with hurricanes alone
causing $23.5 billion in damage annually to infrastructure. Moreover, rising sea levels will amplify
transportation infrastructure vulnerability to coastal storms, nuisance flooding, and wave actions,
especially towards pavement infrastructure which are critical based on the mileage of the
intermodal transportation network that connects communities, waterways, ports, and rail. To
protect pavement infrastructure from flooding, the state-of-practice involves hard (grey)
structures, raising roadway elevations, reinforcing infrastructure, and relocating roadways further
inland. In the last decade, federal agencies such as NOAA, FHWA, and USACE have led an
initiative to explore the design and integration of natural and nature-based features (NNBFs) in
increasing the resilience of transportation infrastructure while providing ecosystem benefits.
Natural features are existing ecosystems that include coastal marshes and wetlands, dune and
beach systems, oyster and coral reefs, forests, coastal rivers and floodplains, and barrier islands
that provide multiple benefits to communities, such as storm protection through wave attenuation
or flood storage capacity and enhanced water services and security. In recent years, the FHWA
also began exploring NNBFs as innovative green infrastructure to protect coastal highways,
starting with an implementation guide and pilot studies. Before NNBFs can be effectively
transferred into practice in Louisiana, there is an important need to establish the level of flood
protection and economic metrics to compare NNBFs and grey infrastructure; and to assess the
long-term efficacy of NNBFs to protect transportation infrastructure under a range of flooding
scenarios. The overarching objective of this research project is to establish the level of flood
protection and economic metrics to compare natural and nature-based features (NNBFs) and
grey infrastructure; and to assess the long-term efficacy of NNBFs to protect transportation
infrastructure under a range of flooding scenarios. The objectives of this research project is to (1)
evaluate the damage to transportation infrastructure after Hurricane Ida, (2) evaluate the efficacy
of grey infrastructure and NNBFs to provide hurricane surge and wave protection, and (3) quantify
the potential economic benefits of NNBFs to its resiliency towards extreme events. Hurricane Ida
case studies near Port Fourchon and Grand Isle will be used as case studies to evaluate the
performance of roadway and bridge infrastructure, along with NNBFs (beach and dunes,
wetlands, and mangroves). The findings of this research will result in a better understanding of
natural and nature-based features for protecting of coastal transportation infrastructure systems
for the states in the South Central area and all other States as they are all prone to the adverse
effects of natural disasters. A final report will detail information on the methodology used for this
research and data acquisition of pertinent information for NNB natural disasters such as the
condition of flood control structures, power lines, street level conditions of roads, rising water
levels, number of damaged homes and waste debris piles, among many other.]]></description>
      <pubDate>Fri, 06 May 2022 11:20:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/1948616</guid>
    </item>
    <item>
      <title>Deterioration of sea sand roller compacted concrete used in island reef airport runway under salt spray</title>
      <link>https://trid.trb.org/View/1905958</link>
      <description><![CDATA[The river sand was replaced by untreated sea sand in roller compacted concrete (RCC) subjected to the salt spray cycles which was produced by 5% sodium sulfate solution. The relative elastic modulus, the mass loss in the wear resistance test, the fatigue impact resistance, the flexural and the compressive strength were investigated. The results show that the relative elastic modulus is decreased by 3.8% and 1.3%, the mass loss in the wear resistance test is increased by 27.9% and 11.9% when sea sand RCC and river sand RCC are subjected to 400 salt spray cycles. The compressive and the flexural strength of sea sand RCC with 400 salt spray cycles is decreased by 32.3%. and 14.8%, respectively. The fatigue impact resistance of sea sand RCC and river sand RCC is decreased by 37.3% and 21.2% when the salt spray cycles are raised from 100 cycles to 400 cycles.]]></description>
      <pubDate>Mon, 28 Feb 2022 09:40:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1905958</guid>
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