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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Experimental and numerical studies on the impact performance of bridge barriers</title>
      <link>https://trid.trb.org/View/2703114</link>
      <description><![CDATA[Roadside safety barriers are critical infrastructure that mitigate collision damage through containing and redirecting errant vehicles. However, experimental investigations and comprehensive assessments of bridge barrier impact performance remain limited. This study evaluates the impact performance of two in-service bridge barriers (a steel parapet and a cable barrier) experimentally and numerically. First, two 1:2 scaled steel parapet specimens were tested in the laboratory using pendulum impacts at varying velocities and impact locations. The parapet exhibited robust crashworthiness, maintaining structural integrity across all impact scenarios. The peak impact force increased with impact velocity and was sensitive to the structural stiffness at the impact location. Next, six 1:2 scaled cable barrier specimens were tested under two impact scenarios, each encompassing three impact velocities. The cable barrier system underwent progressive damage with increasing impact velocity, transitioning from minor deformation to moderate damage and ultimately to severe structural failure. Refined numerical models of the two pendulum–barrier systems are developed and calibrated. The simulation results show good agreement with experimental measurements in terms of impact force and damage patterns. Based on the validated models and analysis, full-scale vehicle-barrier collision simulations are finally performed to assess barrier performance under representative crash conditions. Results demonstrate that the steel parapet exhibits higher structural stiffness under impact. The cable barrier dissipates energy through notable wire rope deformation but yields higher occupant ridedown acceleration during vehicle–post interaction. The findings provide a valuable reference to bridge barrier impact performance and offer guidance for barrier design optimization.]]></description>
      <pubDate>Tue, 01 Sep 2026 09:09:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2703114</guid>
    </item>
    <item>
      <title>Barrier Delineation in Work Zones: The Well-Defined Path [video]</title>
      <link>https://trid.trb.org/View/2727296</link>
      <description><![CDATA[This video focuses on the delineation of portable concrete barriers in construction and work zones. Topics covered include: standards, placement situations, delineation techniques, end treatments, maintenance considerations, and selection of delineation devices.]]></description>
      <pubDate>Tue, 21 Jul 2026 16:16:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2727296</guid>
    </item>
    <item>
      <title>Mathematical Modeling of Vehicle Impact Against a Rigid Barrier</title>
      <link>https://trid.trb.org/View/2581405</link>
      <description><![CDATA[This paper presents a series of mathematical models from the reference ones, up to the concept model developed based on them. The presented mathematical models study the frontal collision between the vehicle and a rigid barrier. The developed model simulates the movement of the occupant during the frontal impact. After obtaining the equations of motion, the graphs of the kinematic parameters (velocity and acceleration) are displayed in MATLAB SIMULINK.]]></description>
      <pubDate>Mon, 13 Jul 2026 10:46:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2581405</guid>
    </item>
    <item>
      <title>MASH Evaluation of Minnesota Department of Transportation Bicycle and Pedestrian Bridge Rail and Hybrid Bridge Rail</title>
      <link>https://trid.trb.org/View/2691797</link>
      <description><![CDATA[The Minnesota Department of Transportation (MnDOT) currently uses two bridge rail systems that are configured with a concrete bridge rail and a steel beam and post rail. The first is a concrete bridge rail with an attached bicycle and pedestrian rail and the second is a hybrid concrete bridge rail with a lower brush curb and an upper steel beam and post railing structure. Both bridge railings were previously developed and successfully crash tested under the safety criteria of NCHRP Report 350. MnDOT desired to evaluate these bridge railings to the current safety standards of AASHTO’s 𝘔𝘢𝘯𝘶𝘢𝘭 𝘧𝘰𝘳 𝘈𝘴𝘴𝘦𝘴𝘴𝘪𝘯𝘨 𝘚𝘢𝘧𝘦𝘵𝘺 𝘏𝘢𝘳𝘥𝘸𝘢𝘳𝘦 (MASH). The concrete railing with a bicycle and pedestrian rail was crash tested to MASH TL-3, and it satisfied all safety criteria for MASH test 3-11. The hybrid bridge railing was subjected to all three prescribed crash tests in the MASH TL-4 matrix. The two tests with passenger vehicles were conducted near the downstream end transition to a concrete end buttress to evaluate vehicle snag, while the single-unit truck test was conducted near the middle of the rail to evaluate the railing’s strength. The hybrid railing passed all safety performance criteria.]]></description>
      <pubDate>Tue, 14 Apr 2026 10:08:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2691797</guid>
    </item>
    <item>
      <title>QUICKCHANGE Moveable Concrete Barrier System</title>
      <link>https://trid.trb.org/View/2680603</link>
      <description><![CDATA[Highway construction operations must often be carried out in locations adjacent to active traffic lanes. When this happens, both workers and motorists are exposed to greater hazard levels than would be the case on a "closed roadway" worksite. Project IR-240-4(324)000 included a situation where contract requirements specified that lane closures could take place only between 7:00 PM and 7:00 AM. Both traffic conditions and the nature of the work on this project indicated a need for a barrier system between construction operations and motorists. A Quickchange Moveable Concrete Barrier (QMCB) System was purchased to meet the requirements of this project. The QMCB System was evaluated by the Oklahoma Department of Transportation (ODOT) Research and Development Division. During Project IR-240-4(324)000 14,600 L.F. of QMCB Barrier was produced by a subcontractor and used on this project. 88 separate QMCB barrier wall shifts were made during work on the project. A total of 393,101 L.F. of QCMB barrier was shifted. Information regarding barrier wall shifts was obtained by monitoring shifts, and by interviewing ODOT Construction personnel and contractor's employees. During the study, numerous collisions involving the QMCB Wall occurred. Only 12 of these accidents were reported to authorities. Accident Reports were requested from the Oklahoma Department of Public Safety. Selected items of information from these reports were analyzed. Performance of the QMCB System on this project was considered to be positive, both from an operations standpoint, and regarding its effectiveness as a protective barrier.]]></description>
      <pubDate>Sat, 04 Apr 2026 17:15:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2680603</guid>
    </item>
    <item>
      <title>Delineation of Linear Roadside Hardware Systems and Roadside Obstacles</title>
      <link>https://trid.trb.org/View/2682135</link>
      <description><![CDATA[This report provides information on the practices for delineating linear roadside hardware systems and roadside obstacles, including their descriptions, effectiveness, and appropriate applications. This information was developed from (1) a review and evaluation of current practices relevant to the delineation of linear roadside hardware systems and roadside obstacles, (2) an analysis of crash data and the effectiveness of delineation practices in reducing crash severity or crash frequency, and (3) a human factors study evaluating the effectiveness of several roadside hardware and roadside obstacle delineation practices. The information contained in this report will help highway agencies and other organizations concerned with safety aspects on highways make informed decisions regarding the delineation of roadside hardware and obstacles to reduce crashes and improve safety.]]></description>
      <pubDate>Sun, 22 Mar 2026 17:18:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2682135</guid>
    </item>
    <item>
      <title>A Crash Robustness Design for an AC-MPDB Based on a Bi-Directional Segmentation Scheme</title>
      <link>https://trid.trb.org/View/2646854</link>
      <description><![CDATA[This paper develops an Advanced Chinese-Moving Progressive Deformable Barrier (AC-MPDB) with a bi-directional block design to address the limitations of existing moving progressive deformable barriers in accurately reflecting the dynamic response of the vehicle-to-vehicle crash. A comprehensive crashworthiness assessment of the AC-MPDB revealed certain stability issues under specific conditions. By analysing the mechanical properties of honeycomb aluminum and the design characteristics of the barrier, the root causes of these stability issues were identified, and corresponding robustness enhancement solutions were proposed. New evaluation indicators were developed for specific conditions, and the proposed solutions were validated and assessed. The results show that the optimized design offers improved crash robustness and can effectively represent the front-end structure of vehicles, providing a reliable tool for future safety evaluation protocols.]]></description>
      <pubDate>Fri, 20 Mar 2026 14:47:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2646854</guid>
    </item>
    <item>
      <title>A Multi-Lane Cellular Automaton Model Based on Non-Motorized Lane Occupancy Behavior</title>
      <link>https://trid.trb.org/View/2613319</link>
      <description><![CDATA[In order to study the impact of non-motorized vehicles’ lane-occupying behavior on motorized vehicles’ driving, for the shortcomings of the STCA model, which can only simulate the behavior of vehicles on two lanes, this study proposes the addition of a non-motorized lane based on the STCA model. The simulation of motorized and non-motorized barriers is added as a comparison to reflect the impacts of non-motorized lane occupancy on motorized vehicles by analyzing lane congestion, speed changes between motorized vehicles and non-motorized vehicles, and the lane-changing rate of the two. The results show that the installation of the motorized and non-motorized barriers has effectively improved the efficiency of motor vehicle traffic, resulting in an increase in the average speed of motor vehicles by about 13.13% and the maximum speed of motor vehicles by about 16.43%. And it validates the conjecture that, to some extent, the higher the flow of non-motorized vehicles, the greater the impact on motorized vehicles.]]></description>
      <pubDate>Fri, 20 Mar 2026 14:10:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2613319</guid>
    </item>
    <item>
      <title>Real life motorcycle crashes into road barriers – does motorcyclists’ injury severity vary between different types of barriers and the presence of motorcycle protection systems?</title>
      <link>https://trid.trb.org/View/2663649</link>
      <description><![CDATA[ObjectiveThis paper set out to investigate and compare injury outcomes among motorcyclists injured in crashes into different types of road barriers, and if Motorcycle Protection Systems (MPS) installed on barriers result in any injury mitigation in real-life conditions.MethodsInformation on motorcyclist crashes involving roadside barriers was accessed from two different databases, the Swedish Traffic Accident Data Acquisition, a national information system containing data on traffic accidents and injuries occurring in the Swedish road transport system, and the Transport Accident Commission injury database in Victoria, Australia. Barrier types and the presence of MPS were determined by using photographs of the reported crash site available in the Google Maps Street view feature. Injury outcome was compared using three different injury severity metrics, Fatal and Serious Injury ratios (FSI-ratio), Maximum Abbreviated Injury Scale (MAIS) and mean Risk of Permanent Medical Impairment (RPMI) of at least 1% (mRPMI 1%+) and at least 10% (mRPMI 10%+).ResultsNo significant differences were observed between different types of barriers, for any of the injury metrics. In Sweden, FSI ratios varied between 49–60% in speed limits =70?km/h. In Victoria the number of minor injuries was underreported, resulting in higher FSI ratio varying between 73–89% in speed limits =80?km/h. The analysis of MPS showed that there was a significant difference in the fatality risk where significantly fewer motorcyclists were fatally injured in a crash involving a barrier with MPS compared to a barrier without MPS. This difference was observed in curves on roads with a speed limit =70?km/h.ConclusionsThe risk of fatal or serious injury is generally higher for crashes involving road barriers, compared to all crash types. No significant difference in injury outcome was observed between different types of barriers at speed limits =70?km/h. In curves on roads with a speed limit =70?km/h, MPS results in a significantly lower risk of fatality, compared to a barrier without MPS.]]></description>
      <pubDate>Wed, 18 Mar 2026 09:00:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663649</guid>
    </item>
    <item>
      <title>Barrier Striping for the Reduction of Accidents</title>
      <link>https://trid.trb.org/View/2676924</link>
      <description><![CDATA[Barrier striping is a roadway safety countermeasure designed to enhance driver awareness of concrete barriers, particularly under adverse weather and low-visibility conditions. This study evaluated the short- and long-term safety effectiveness of retroreflective barrier striping across multiple sites in Texas. The research involved a comprehensive literature review of barrier delineation practices, a detailed examination of existing installations, and the implementation and evaluation of new treatments at selected high-crash locations. Data collection included crash records, roadway geometry, traffic volume, meteorological conditions, and probe vehicle speed data. Analytical methods encompassed descriptive statistics, crash rate comparisons, logistic and linear regressions, Negative Binomial, and survival analysis to assess the impact of striping on crash frequency, severity, and operating speeds. The findings revealed notable reductions in barrier-related crashes at treated sites, with relatively stronger improvements observed at nighttime, underscoring the benefits of increased retro-reflectivity. Speed analysis suggested limited but measurable effects on vehicle operating behavior. Based on these results, the project team refined the Texas Department of Transportation’s draft special specification for barrier striping, offering updated guidance on materials, spacing, and installation procedures. Overall, barrier striping demonstrates promising potential as an effective countermeasure to improve roadway safety, though continued evaluation and site-specific considerations are recommended. Future research should further explore surrogate safety measures, maintenance requirements, and the effectiveness of alternative striping materials.]]></description>
      <pubDate>Fri, 13 Mar 2026 08:45:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2676924</guid>
    </item>
    <item>
      <title>Human Factors Study to Understand Driver Behavior on Managed Lane Facilities</title>
      <link>https://trid.trb.org/View/2663284</link>
      <description><![CDATA[The Florida Department of Transportation (FDOT) has several managed lane facilities throughout the state. Managed lanes (MLs) are commonly constructed adjacent to general-purpose lanes (GPLs) to improve mobility. The objective of this research was to understand driver behavior on managed lane facilities, specifically pertaining to the type of separation between the MLs and the GPLs. This research employed a naturalistic driving study and a driving simulator study to examine how separation type affects driver behavior on ML facilities. Three separation types; pylons, buffer areas, and concrete barriers were analyzed utilizing naturalistic driving data, while two separation treatments; separation width defined by single solid lines or double solid lines, and separation height defined by 24" or 28" in curved sections were analyzed utilizing the driving simulator. The driving simulator study was conducted at the University of Central Florida (UCF) using a compact version (miniSimTM) of the National Advanced Driving Simulator (NADS) developed by the University of Iowa. Participants experienced various driving scenarios along a 6-mile roadway with single-lane ML and 2-lane ML sections. Separation width (single solid or double solid lines) was examined in both straight and curved sections, while separation height (24-inch and 28-inch pylons) was evaluated only in curved sections. Results revealed higher mean speeds and shorter fixation durations with double solid lines combined with 28-inch pylons in curved segments. Lane deviation away from the separator was greater with double solid lines combined with 24-inch pylons. Over half of the participants reported double solid lines and 28-inch pylons as being more noticeable. The naturalistic driving study examined how drivers behave in the real world on ML facilities with different separation treatments. Data from ML facilities in Florida and Washington State was collected from the Regional Integrated Transportation Information System (RITIS) and the Second Strategic Highway Research Program (SHRP2), respectively. Performance measures analyzed included lane utilization, travel speed, and lane deviation. Findings revealed that concrete barriers and pylon separations result in decreased lane utilization compared to buffer separation by 12.8% and 8.6%, respectively, on the leftmost GPL. On the rightmost ML, lane utilization increased by 2% with concrete barriers and decreased by 20% with pylon separations compared to buffer separation. Buffer separation resulted in higher average speeds on MLs. Drivers in the ML adjacent to the separator tend to drive away from the separator for all separation types, with the greatest magnitude observed on buffer-separated ML facilities. This research provides FDOT and other transportation agencies with a better understanding of the effects of different ML separation treatments between the MLs and GPLs on driver behavior, enabling agencies to implement treatments aimed at improving safety and mobility on ML facilities.]]></description>
      <pubDate>Fri, 20 Feb 2026 08:49:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663284</guid>
    </item>
    <item>
      <title>Evaluating the Performance of Concrete Barriers in Protecting Bridge Piers under Vehicular Impact in Space-Constrained Settings</title>
      <link>https://trid.trb.org/View/2663261</link>
      <description><![CDATA[Unprotected bridge piers are exposed to vehicular impact loads that can significantly exceed the code-specified design load, posing a significant risk of structural damage. Although protective barriers offer an efficient means of mitigating these risks, the effectiveness of these barriers for bridge piers is strongly influenced by space constraints between the piers and barriers. Barriers placed adjacent to piers may directly transfer impact forces and cause severe damage, while those placed with inadequate offsets can experience intrusion of vehicle components. This study evaluates the performance of a standard 1,372 mm (54 in.) pier protection barrier in adjacent and minimally spaced configurations using high-fidelity finite-element analysis. A sensitivity analysis is conducted to determine the effect of barrier height and offset distances on impact force transfer between tractor-trailers and piers in constrained spaces. Results indicate that increasing the spacing from 25 mm (1 in.) to 75 mm (3 in.) reduces the rear trailer impact force on the bridge pier by 75% for the studied cases. Additionally, increasing the height of the 1,372 mm (54 in.) tall barrier by 25 mm (1 in.) can completely mitigate the impact force due to the rear of the trailer. However, the front trailer impact force is less sensitive to changes in both height and spacing, requiring a barrier height of at least 1,422 mm (56 in.) with 50 mm (2 in.) to 75 mm (3 in.) spacing. Additionally, increasing barrier height is the most effective strategy in preventing load transfer, even in space-constrained settings.]]></description>
      <pubDate>Tue, 17 Feb 2026 10:30:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663261</guid>
    </item>
    <item>
      <title>Study on Vehicle Collision Results under the AC-MPDB Scheme</title>
      <link>https://trid.trb.org/View/2628412</link>
      <description><![CDATA[With the iteration of vehicle brand design, the applicability of the current Mobile Progressive Deformable Barrier (MPDB) scheme has declined. The Advanced Chinese Mobile Progressive Deformable Barrier (AC-MPDB) is introduced, which incorporates segmented Z-directional design and increased mass distribution to better align with the Chinese vehicle front-end structure. This study utilizes Camry and Rogue models to design an MPDB-to-vehicle and a vehicle-to-vehicle simulation matrix. The compatibility of the barrier schemes, Euro-NCAP MPDB (E-MPDB) and AC-MPDB, is evaluated using energy equivalent speed, occupant load criteria, peak force, and acceleration. The simulation results indicate that, compared to E-MPDB, the AC-MPDB barrier scheme exhibits excessive stiffness for medium-sized sedans with smaller mass but demonstrates better compatibility with SUVs. Further analysis of the target vehicle's longitudinal beam deformation animation and pedal intrusion reveals that AC-MPDB achieves superior vehicle reproducibility, particularly for SUVs.]]></description>
      <pubDate>Mon, 09 Feb 2026 08:43:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2628412</guid>
    </item>
    <item>
      <title>Vortex-induced vibration of box girders with non-uniformly arranged crash barriers</title>
      <link>https://trid.trb.org/View/2632207</link>
      <description><![CDATA[This study investigates the aerodynamic influence of Non-Uniformly Arranged Crash Barriers (NUACB) on box girder vortex-induced vibration (VIV) through large-scale sectional model wind tunnel tests. The analysis covers spectral characteristics, velocity field and spanwise evolution, as well as spatial distributions of turbulence intensity and streamwise turbulence integral length scale. The results show that the girder exhibits pronounced vertical bending VIV at 3° and 5° angles of attack (AoAs). Its drivers include spectral energy concentration near the lock-in frequency in leeward and wake regions; accelerated windward shear-layer growth with associated leeward flow separation; elevated overall turbulence intensity; and formation of spanwise-coherent vortical structures on the top surface and in the wake. NUACB effectively suppresses VIV by attenuating resonance-frequency spectral peaks, inhibiting shear-layer maturation, stabilizing leeward flow attachment, and promoting wake recovery. It also significantly reduces turbulence intensity and streamwise integral length scales in critical zones, thereby disrupting spanwise coherence of vortex shedding. Although localized vortices persist near blocked segment edges, sustained spanwise synchronization is eliminated. Based on these findings, we propose the Turbulence-Regulated Vibration Suppression Theory (TRVST). TRVST holds that targeted aerodynamic interventions can reconfigure bluff-body turbulence, disrupt shear-layer evolution, and preclude spanwise vortex formation from inception. This approach is validated by combined turbulence-based metrics and offers a new framework for aerodynamic VIV suppression in bridge engineering.]]></description>
      <pubDate>Thu, 22 Jan 2026 09:24:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2632207</guid>
    </item>
    <item>
      <title>A new reliable and easily applicable approach to establish a road crash barriers maintenance priority</title>
      <link>https://trid.trb.org/View/2627502</link>
      <description><![CDATA[In recent years, in Italy Road Public Authorities paid great attention about the maintenance condition of road crash barriers, whose maintenance priority is often the result of reports by road users or in consequence of damages resulting from accidents, without a real maintenance plan. In the past, in Italy some algorithms have already been developed to establish a maintenance priority based on objective considerations, which require the recognition of the road network under the responsibility of each Authorities and the inspection of all the roadsides. These algorithms were mainly based on the risk analysis evaluation, carried on by solving the event tree with the definition of some indexes (related to dangerousness, vulnerability and exposure) and assigning a weight coefficient to each of them. Even if these algorithms were successfully applied by more than one Road Authorities in Italy, they did not completely resolve the issue, because they leave to the engineers the burden of determining the weight coefficients as well as their possible relation. The present research aims to overcome this limitation by the application of a MADM (Multiple Attribute Decision Making) methodology based on Gray Relational Analysis (GRA), which allows to solve numerous types of problems characterized by complex interrelationships between the different parameters and variables used to describe them. Applied to the case of prioritization maintenance on existing road barriers, considering each single barrier as a possible alternative, the GRA methodology allows to combine the entire range of values of any performance attributes considered for each alternative into a single value, overcoming the assignment of weight to each attribute arbitrarily, and effectively reducing the original problem to a decision problem with a single attribute. The final result is the ranking, based on the score obtained by any road crash barrier, which allows to establish the maintenance priority.]]></description>
      <pubDate>Fri, 09 Jan 2026 14:44:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2627502</guid>
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