<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
    <description></description>
    <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>
    </image>
    <item>
      <title>Research on the Prediction of Driver Fatigue Degree Based on EEG Signals</title>
      <link>https://trid.trb.org/View/2646877</link>
      <description><![CDATA[OBJECTIVE: Predicting driver fatigue degree is crucial for traffic safety. This study proposes a deep learning model utilizing electroencephalography (EEG) signals and multi-step temporal data to predict the next time-step fatigue degree indicator percentage of eyelid closure (PERCLOS) while exploring the impact of different EEG features on prediction performance., APPROACH: A CTL-ResFNet model integrating CNN, Transformer Encoder, LSTM, and residual connections is proposed. Its effectiveness is validated through two experimental paradigms, Leave-One-Out Cross-Validation (LOOCV) and pretraining-finetuning, with comparisons against baseline models. Additionally, the performance of four EEG features-differential entropy, alpha/beta band power ratio, wavelet entropy, and Hurst exponent-is evaluated, using RMSE and MAE as metrics., MAIN RESULTS: The combined input of EEG and PERCLOS significantly outperforms using PERCLOS alone validated by LSTM, and CTL-ResFNet surpasses baseline models under both experimental paradigms. In LOOCV experiments, the alpha/beta band power ratio performs best, whereas differential entropy excels in pretraining-finetuning., SIGNIFICANCE: This study presents a high-performance hybrid deep learning framework for predicting driver fatigue degree and reveals the applicability differences in EEG features across experimental paradigms, offering guidance for feature selection and model deployment in practical applications.]]></description>
      <pubDate>Wed, 31 Dec 2025 10:56:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2646877</guid>
    </item>
    <item>
      <title>Evaluation of a Low-Activity Nuclear Density Gauge for Acceptance Testing of Asphalt Pavements for Percent-Within-Limit and Averaging Specifications</title>
      <link>https://trid.trb.org/View/2582347</link>
      <description><![CDATA[Compaction of asphalt concrete (AC) to a specific density is required to achieve the designed engineering properties and performance characteristics of a pavement layer. The finished AC layers do not exhibit uniform density because of variability in production and construction processes. Nuclear density gauges (NDG) are used for density acceptance testing because of their favorable measurement properties, that is, sensitivity, precision, depth of measurement or investigation, and accuracy. This study evaluated a recently developed direct transmission-mode-based method for low-activity nuclear density gauges (LNDG-TM), which notably, are exempt from US nuclear regulatory restrictions. The measurement precision of the LNDG-TM method was determined from a six gauge–operator pair inter-laboratory study. The repeatability and reproducibility standard deviations were 0.7 lb/ft3 (11 kg/m3) and 1.0 lb/ft3 (16 kg/m3), respectively. The materials and construction density variability (dMC) for an interstate surface course were determined by analyzing control-strip density data. The dMC at the 95% confidence level, as determined with the core extraction (CE) method, was 2.3 lb/ft3 (37 kg/m3), whereas those determined with two NDGs were 3.0 lb/ft3 (48 kg/m3) and 2.2 lb/ft3 (35 kg/m3), respectively. The LNDG-TM method was evaluated for acceptance testing, wherein the provided density specifications were the percent-within-limit (PWL) and averaging. Two surface courses were tested: one with the PWL specification wherein the CE method was the agency-approved method, and the other with the averaging specification, wherein the agency-approved method was the thin-lift NDG method. For both projects, results from using the LNDG-TM method agreed well with those obtained using the agency-approved methods. Thus, the LNDG-TM method is suitable for density acceptance testing of asphalt pavements.]]></description>
      <pubDate>Tue, 29 Jul 2025 13:55:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2582347</guid>
    </item>
    <item>
      <title>Evaluation of Resilient Modulus Prediction Models for Saturated Pavement Base Aggregates</title>
      <link>https://trid.trb.org/View/2567078</link>
      <description><![CDATA[Given the increased frequency of heavy rainfall, there is a high probability that pavement base aggregates in the field, particularly in coastal regions, will become saturated and remain so for extended periods. The increase in moisture content can reduce the resilient modulus (MR) of base materials. There are numerous constitutive models that help predict the resilient modulus of base aggregates based on moisture content and stress states, to assist pavement design. The performance of most of these models has been evaluated previously, but not at full saturation. This study is an evaluation of the two best performing prediction models, as determined in previous studies and current practices. The assessment was carried out using MR test data for seven laboratory-saturated base aggregates with different properties and moisture sensitivities (high and low). The models were first calibrated based on MR results at the optimum moisture content and then used to predict MR of each base material at saturation. The accuracy of the prediction and the applicability to base aggregates with different moisture sensitivities formed the basis of the evaluation. The models were found to be more accurate and even conservative when predicting MR of saturated base aggregates with low moisture susceptibility. However, the models were erroneous in their prediction and overestimated MR at saturation of highly moisture susceptible pavement base aggregates. An adaptation solution was proposed to improve the prediction accuracy of the existing models. This study joins efforts to design our climate-vulnerable roadways more accurately and improve pavement resilience.]]></description>
      <pubDate>Mon, 23 Jun 2025 18:38:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2567078</guid>
    </item>
    <item>
      <title>Resilient and rutting response of unbound granular material and subgrade soil influenced by initial state and stress conditions</title>
      <link>https://trid.trb.org/View/2539936</link>
      <description><![CDATA[Unbound pavements with thin seals, where traffic loads are primarily supported by unbound granular layers and subgrade soil, are favoured for their low initial cost. Rutting, the primary distress mechanism, leads to rough, uncomfortable surfaces, diminishing serviceability and safety. It depends on the material's initial dry density, degree of saturation, and applied stress levels. Resilient modulus, indicating layer stiffness, is crucial for determining load transmission to underlying layers, making accurate estimation essential for pavement design. This study conducted constant radial stiffness triaxial (CRST) tests on an unbound granular material and a subgrade soil at various dry densities, saturation degrees, and stress conditions. The CRST test applies dynamic confining pressure under constant radial stiffness boundary. New models for rutting and resilient modulus were developed, relating these parameters to initial dry densities, saturation degrees, and stress states. The study also presents rutting and resilient modulus isograms on the compaction plane, aiding field compaction control and robust pavement design.]]></description>
      <pubDate>Fri, 23 May 2025 15:36:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2539936</guid>
    </item>
    <item>
      <title>Effect of Saturation on Performance of Steel Slag Ballast under Cyclic Rail Loads</title>
      <link>https://trid.trb.org/View/2516589</link>
      <description><![CDATA[Steel slag is becoming a popular alternative to conventional natural ballast in a ballasted rail track under a circular economy paradigm. The mechanical behavior of ballast has a significant impact on the overall performance of the track, particularly during monsoons due to heavy rain or flooding, which may further alter the track performance. The present study aims to investigate the effect of saturation on the performance of steel slag ballast under monotonic and cyclic loading. The performance is quantified in terms of shear strength, resilient modulus, permanent deformation, damping ratio, and crushing strength behavior. A comparative study of four different steel slag ballasts and granite (one of the most commonly used ballast materials) was conducted using laboratory tests, including the monotonic triaxial test, cyclic triaxial test, and single-particle crushing strength test for dry and saturated conditions. The results show that the presence of free lime content and saturation adversely affect the behavior of steel slag. Empirical relations are proposed for assessing the resilient modulus and damping ratio of steel slag ballast from single-particle crushing strength, abrasion resistance, free lime content, and water absorption value. A prediction model is proposed to predict the permanent strain accumulation taking into account key factors such as water absorption, specific gravity, and free lime content, which can be helpful in the construction and maintenance of railways.]]></description>
      <pubDate>Fri, 23 May 2025 15:34:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2516589</guid>
    </item>
    <item>
      <title>Digital twinning for ports : from characterization to operations' modelling</title>
      <link>https://trid.trb.org/View/2491219</link>
      <description><![CDATA[Ports are actively pursuing greater operational efficiency to effectively handle the increasing global flow of goods, while striving to improve the energy efficiency of their operations to comply with new environmental regulations. As a result, innovation-leading ports have begun to recognize the potential of digital twins to overview, coordinate and optimize port processes, resulting in energy savings, and reductions of costs and of CO2 emissions. While digital twins have gained momentum in other domains such as smart manufacturing and aerospace, their adoption in ports has been comparatively slow. This can be explained, among other things, by the multi-stakeholder nature of the port and the high complexity of the often interconnected port processes. Thus, this thesis, grounded in the context of ports, discusses what constitutes a digital twin, proposes characteristics to assess the maturity of existing digital twins, and introduces and evaluates mathematical models to support a key port process, which can be used as components of a digital twin for the port.]]></description>
      <pubDate>Fri, 17 Jan 2025 15:16:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/2491219</guid>
    </item>
    <item>
      <title>Constructability as Design Objective</title>
      <link>https://trid.trb.org/View/2470496</link>
      <description><![CDATA[Bridge construction is a challenging engineering discipline which requires a good understanding of technology and structural behaviour. Generally, superstructure type, material, weight, availability of equipment, technical know-how, local conditions, schedule, and much more influence the means and methods of bridge construction. Especially for major and complex bridges, the choice of a cost-effective and reliable erection method as well as a diligent construction engineering approach are paramount for success. But even standard bridges require utmost attention in this regard because each situation is somehow different. As several factors influence bridge constructability, it is of importance that a cost-effective and reliable erection method is developed in the conceptual design stage, rather than in the construction stage where most design parameters are effectively locked-in. Adjusting bridge design parameters at the construction stage due to constructability concerns can result in significant costs and delays. Conversely, considering constructability at the design stage prevents cost and schedule overruns, and yields synergistic efficiency gains by jointly addressing constructability and limit state requirements. Via case studies of three complex steel bridge projects, this paper will demonstrate the importance of constructability as a design objective. It describes how the aspect of constructability was implemented in the design phases to confirm that the following construction phases could be executed without costly revisions and delays. In all three situations, the overarching goal was to capitalize on synergy effects and efficiency without compromising safety, structural integrity, and durability. Hereby, design and construction reliability was achieved by addressing constructability as a design objective.]]></description>
      <pubDate>Wed, 08 Jan 2025 13:52:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2470496</guid>
    </item>
    <item>
      <title>Saturation evolution induced by suction effect in asphalt mixtures during air-water two-phase seepage</title>
      <link>https://trid.trb.org/View/2467159</link>
      <description><![CDATA[The unsaturated service state of asphalt pavements caused by air-water two-phase retention and flow is the intrinsic cause of moisture damage and durability deterioration of the asphalt mixture. However, the mechanism by which matric suction, as one of the key driving forces, affects the retention and flow behavior of unsaturated asphalt mixtures has not been understood. Hence, the objectives of this study were to (1) investigate the saturation evolution induced by the suction effect in asphalt mixtures during air-water two-phase seepage and (2) clarify the characteristic relationship between equilibrium saturation and matric suction. Three different types of asphalt mixture were produced in the laboratory. An air-driven water replacement experiment with a controlled suction gradient was conducted to describe the evolution of water saturation induced by different matric suction conditions. The results showed that, at a specific suction level, the evolution of water saturation exhibited two stages: a rapid drainage phase and a dynamic stabilization phase. On this basis, a sensitivity analysis using the Friedman test revealed that the constituent materials (binder and aggregate types) contributed slightly to desaturation, while the void structure characteristic was the main factor influencing desaturation in asphalt mixtures. In a stable unsaturated state, the curve of equilibrium saturation and suction indicated that high matric suction meant low saturation and water retention capacity of the asphalt mixture. For the same matric suction, the densely graded asphalt mixtures exhibited a higher overall water retention capacity than the open-graded friction courses. For the same mixture types, the water retention capacity at high void contents exhibited a more significant sensitivity than that at a low void content. These results contribute to reasonably evaluating the unsaturated hydraulic characteristics in asphalt mixtures, and these characteristics indirectly guide the selection of asphalt pavement materials and structures in areas with frequent dry-wet cycles and freeze-thaw cycles, as well as the measures to prevent moisture damage.]]></description>
      <pubDate>Fri, 20 Dec 2024 10:28:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2467159</guid>
    </item>
    <item>
      <title>Enhancing sand liquefaction resistance through microbial-induced partial saturation: An experimental study</title>
      <link>https://trid.trb.org/View/2420304</link>
      <description><![CDATA[The liquefaction potential of saturated sand can be significantly reduced by inducing partial saturation in the soil. Conventional soil liquefaction mitigation methods, namely soil densification, drainage, cementing, and groundwater lowering, pose environmental concerns and are challenging to apply to pre-existing structures. However, the microbially induced partial saturation (MIPS) method is emerging as a novel and eco-friendly approach to mitigate liquefaction. The MIPS method involves microbial denitrification, which produces nitrogen gas and results in a desaturating effect in the saturated soil. The current study conducted a series of stress-controlled undrained cyclic triaxial tests on saturated sandy soil and microbially-desaturated sandy soil under different relative densities and loading conditions. In addition, the study systematically analyzed the effects of temperature and pH on bacterial activity and the denitrification process. Batch experiments were conducted to establish a relationship between the initial nitrate concentration in the bacterial media and the resulting desaturation.Comprehensive analyses of cyclic resistance curves were performed to gain a thorough understanding. Additionally, the study conducts detailed analyses of the accumulation of excess pore pressure and the resulting axial strains and deformation patterns in both treated and untreated sand. This study demonstrates that the MIPS treatment considerably enhances the liquefaction resistance of treated sand.]]></description>
      <pubDate>Thu, 19 Sep 2024 09:14:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2420304</guid>
    </item>
    <item>
      <title>Logistic Simulations to Assess the Effect of Florida Department of Transportation’s Incentive and Disincentive Specifications on Long-Term Asphalt Pavement Performance</title>
      <link>https://trid.trb.org/View/2395099</link>
      <description><![CDATA[The Florida Department of Transportation’s (FDOT’s) percent within limits (PWL) specification for acceptance and payment of asphalt materials was first implemented in 2002. The objective of this study was to determine the effect that FDOT’s PWL specification has on the long-term performance of asphalt pavements. In this study, multinomial logistic regression analysis (MLRA) was used to assess the effect of FDOT’s PWL specification on long-term asphalt pavements. The MLRA results were used to determine the probability of a pavement section showing a higher level of long-term distress as a function of the composite pay factor (CPF). This probability indicates that FDOT’s CPF is cost-effective (i.e., the higher the CPF, the lower the probability of distress). Moreover, it was shown that CPF has a profound effect on cracking and raveling of both dense and open graded mixtures. The results of additional logistic simulation for dense graded mixtures indicate that FDOT’s new CPF weightings, implemented in the 2019 specification, may result in improved mixture quality and significantly reduce the probability of long-term cracking and raveling, compared with the original weightings in the 2002 specification. For open graded mixtures, although FDOT’s CPF original weightings, implemented in 2002 (and still being used), are cost-effective, the results indicate that the probabilities of cracking and raveling may be reduced further by updating the weightings for percentage passing a 3/8-in. sieve and percentage passing a No. 8 sieve.]]></description>
      <pubDate>Tue, 25 Jun 2024 15:12:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2395099</guid>
    </item>
    <item>
      <title>lmpact of lncentive/Disincentive Specifications on Long-term Asphalt Pavement Performance</title>
      <link>https://trid.trb.org/View/2389238</link>
      <description><![CDATA[FDOT’s Percent Within Limits (PWL) specification for acceptance and payment of asphalt materials was first implemented in 2002. The objective of this study was to determine the level of impact that FDOT’s PWL specification has on the long-term performance of asphalt pavements. To meet this objective, Multinomial Logistic Regression Analyses (MLRA) were performed. The results indicated that FDOT’s Composite Pay Factor (CPF) is cost-effective (i.e., the higher the CPF, the lower the probability of distresses). Moreover, it was shown that CPF has a profound effect on cracking and raveling of both dense and open graded mixtures. According to the results of MLRA, it is recommended that FDOT continue to use the AQC weights revised and implemented in 2019 for dense graded mixtures. For open graded mixtures, it is recommended that FDOT explore the option of increasing the weight of Percent Passing 3/8 Inch Sieve (PF_P3.8) by 5 percent and reducing the weight of Percent Passing No. 8 Sieve (PF_P8) by 5 percent.]]></description>
      <pubDate>Mon, 17 Jun 2024 09:38:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2389238</guid>
    </item>
    <item>
      <title>Association of Visual-Based Signals with Electroencephalography Patterns in Enhancing the Drowsiness Detection in Drivers with Obstructive Sleep Apnea</title>
      <link>https://trid.trb.org/View/2381621</link>
      <description><![CDATA[Individuals with obstructive sleep apnea (OSA) face increased accident risks due to excessive daytime sleepiness. PERCLOS, a recognized drowsiness detection method, encounters challenges from image quality, eyewear interference, and lighting variations, impacting its performance, and requiring validation through physiological signals. The authors propose visual-based scoring using adaptive thresholding for eye aspect ratio with OpenCV for face detection and Dlib for eye detection from video recordings. This technique identified 453 drowsiness (PERCLOS >= 0.3 , , CLOSDUR >= 2 s) and 474 wakefulness episodes (PERCLOS < 0.3 and CLOSDUR < 2 s) among fifty OSA drivers in a 50 min driving simulation while wearing six-channel EEG electrodes. Applying discrete wavelet transform, the authors derived ten EEG features, correlated them with visual-based episodes using various criteria, and assessed the sensitivity of brain regions and individual EEG channels. Among these features, theta-alpha-ratio exhibited robust mapping (94.7%) with visual-based scoring, followed by delta-alpha-ratio (87.2%) and delta-theta-ratio (86.7%). Frontal area (86.4%) and channel F4 (75.4%) aligned most episodes with theta-alpha-ratio, while frontal, and occipital regions, particularly channels F4 and O2, displayed superior alignment across multiple features. Adding frontal or occipital channels could correlate all episodes with EEG patterns, reducing hardware needs. The authors' work could potentially enhance real-time drowsiness detection reliability and assess fitness to drive in OSA drivers.]]></description>
      <pubDate>Mon, 20 May 2024 09:17:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/2381621</guid>
    </item>
    <item>
      <title>Predictive Model for Determining Saturation Profiles under Pavements during Flood Events</title>
      <link>https://trid.trb.org/View/2366302</link>
      <description><![CDATA[Pavements are highly susceptible to water infiltration during floods, resulting in reduced serviceability, shortened life span, and poor durability. To enhance pavement resilience and mitigate the rising risks associated with flooding events, this study aims to propose a method to predict the short-term temporal evolution of saturation levels within pavement structures resulting from inundation events. The methodology involves conducting a series of finite-element-based hydraulic simulations considering various influential factors such as pavement structure, subgrade type, groundwater table level, and flooding scenario. Time-descriptive indicators, including peak saturation time and restoration time, are calculated from the simulated volumetric water content data. To capture the complex relationships between the input parameters and output indicators, machine learning (ML) methods are employed to construct a predictive model for saturation profiles during flooding events. The results demonstrate that the 2nd-degree polynomial provides the best fit for the saturation changes within the vadose zone, and the random forest algorithm outperforms other ML methods, achieving the highest accuracy in projecting saturation changes during flooding events. The predictive model offers valuable insights for decision-making processes, including determining the optimal timing to reopen submerged roadways to traffic, and evaluating the moisture damage caused by the inundation. Overall, this research contributes to enhancing pavement resilience and enables the design and management of resilient pavements under changing climate conditions and extreme weather events.]]></description>
      <pubDate>Wed, 17 Apr 2024 17:05:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2366302</guid>
    </item>
    <item>
      <title>Application of percent within limits concepts on a balanced mix design of asphalt mixtures</title>
      <link>https://trid.trb.org/View/2310308</link>
      <description><![CDATA[Many agencies have incorporated rutting, and more recently cracking laboratory tests in the design process of asphalt mixtures with the objective to produce a balance between the stability and durability of the final product. Although this performance-engineered mixture design (PEMD), called here balanced mix design (BMD), offers compelling benefits, it raises a number of questions regarding its compatibility with construction practices. The objective of this work is to relate a BMD method with realistic binder content construction tolerances by applying concepts of a percent-within-limits (PWL) approach to field QC/QA, accounting for the variability of both the laboratory performance tests and construction. Four Arkansas mixes were evaluated using the Illinois flexibility index test (I-FIT) and the asphalt pavement analyzer (APA), for which binder content (Pb) and compaction level (%Gmm) were varied in the laboratory. Monte Carlo simulations were employed to generate binder content variability distributions based on BMD diagrams. New approaches for setting PWL lower and upper specification limits (LSL and USL respectively), as well as a criterion for defining the constructability of a BMD are proposed.]]></description>
      <pubDate>Mon, 15 Apr 2024 10:55:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2310308</guid>
    </item>
    <item>
      <title>Transporteffektivitet och fyllnadsgrad: Analys och åtgärdsförslag för ökat resursutnyttjande : avrapportering etapp 1</title>
      <link>https://trid.trb.org/View/2344810</link>
      <description><![CDATA[This report of stage 1 of the project “Transport efficiency and occupancy rate: Analysis and action proposals for increased resource utilization” (Tryffel) summarizes results from the completed stage and presents the first plan of stage 2. The goal of the first stage is to set-up sub-studies for the work that is motivated by the main purpose of the project. The report problematizes the need to study transport efficiency and highlights why the fill rate does not hold as a measure of transport efficiency at the societal level. Four sub-studies for stage 2 are presented that take their point of departure in the gap of current knowledge regarding transport efficiency.]]></description>
      <pubDate>Tue, 27 Feb 2024 14:26:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2344810</guid>
    </item>
  </channel>
</rss>