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    <title>Research in Progress (RIP)</title>
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    <atom:link href="https://rip.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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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>Research in Progress (RIP)</title>
      <url>https://rip.trb.org/Images/PageHeader-wTitle-RIP.jpg</url>
      <link>https://rip.trb.org/</link>
    </image>
    <item>
      <title>Evaluation of Positive Protection in Work Zones</title>
      <link>https://rip.trb.org/View/2712242</link>
      <description><![CDATA[Positive protection enhances safety in work zones for both users of the transportation system and for workers by providing separation between the work space and motorized traffic. The decision on whether to use positive protection in a given work zone (and what types of measures and strategies to implement) depends on many factors. The objective of this research project is to develop a decision support tool for the use of positive protection in work zones. Attainment of the project objective will fill gaps in existing knowledge and help transportation practitioners to make data-driven decisions regarding the use of positive
protection in work zones. The research approach will include a literature review, the
gathering of information from various states regarding their best practices for providing
positive protection (through a survey and interviews), analysis of data from a series of freeway work zones, and tool development. The research will be implemented through a collaborative effort by a team comprised of work zone safety experts from the University of Missouri (MU) and Michigan State University (MSU). The benefits of this research project will include improved safety for construction work zones through the use of positive protection. The guidelines developed in this research project will be of great value to the practitioners who are responsible for the implementation of positive protection in work zones and will help to facilitate the increased use of positive protection in work zones.]]></description>
      <pubDate>Tue, 09 Jun 2026 12:18:02 GMT</pubDate>
      <guid>https://rip.trb.org/View/2712242</guid>
    </item>
    <item>
      <title>Novel Surge Barriers for Coastal Protection</title>
      <link>https://rip.trb.org/View/2665445</link>
      <description><![CDATA[Surge barriers are large hydraulic structures designed to protect vulnerable infrastructure from coastal storm surges and high tides. Preventing surges from moving into bays and estuaries minimizes the need for other expensive elements of a flood control system, such as levees and floodwalls. Surge barriers can provide cost-effective protection critical transportation infrastructure, such as ports, roads, and bridges. Conventional surge barriers comprise a fixed structure with movable vertically or horizontally opening gates that can be closed during extreme storms and tidal events. Disadvantages of fixed barriers include high cost, sensitivity to waste and silt, vulnerability to blockage by debris, constraints to marine traffic, and environmental impacts. Temporary surge barriers can avoid these disadvantages. This research evaluates three novel temporary barrier concepts: flexible membrane barriers, sinkable floating barriers, and shade curtain barriers. Flexible membrane barriers are self-deploying and permanently located on shore. Buried when not deployed, they rise with rising water due to their buoyancy. Sinkable floating barriers rest on the seabed when not deployed and, when needed, are raised to the surface by pumping air into a tube. Shade curtains are fabric barriers attached to an existing bridge. When not deployed, it is secured to the underside of the bridge deck. In advance of a surge, the fabric curtain is lowered using a sinker-cable system to provide a vertical barrier extending from the bridge deck to the seabed. Hydraulic loads are transmitted from the barrier to the bridge and its foundations, which must be capable of resisting the added loads. This project addresses three key issues related to temporary surge barrier deployment: site and environmental conditions for which temporary surge barriers are appropriate, hydraulic loading on the barriers, and structural/geotechnical design considerations for the barriers.]]></description>
      <pubDate>Wed, 04 Feb 2026 15:18:48 GMT</pubDate>
      <guid>https://rip.trb.org/View/2665445</guid>
    </item>
    <item>
      <title>Novel surge barriers for coastal protection (TAMU)</title>
      <link>https://rip.trb.org/View/2663229</link>
      <description><![CDATA[Surge barriers are large hydraulic structures designed to protect infrastructure from coastal storm surges and high tides. Preventing surges from moving into bays and estuaries minimizes the need for other expensive elements of a flood control system, such as levees and floodwalls. Surge barriers can provide cost-effective protection critical transportation infrastructure, such as ports, roads, and bridges. Conventional surge barriers comprise a fixed structure with movable vertically or horizontally opening gates that can be closed during extreme storms and tidal events. Disadvantages of fixed barriers include high cost, sensitivity to waste and silt, potential debris blockage, and constraints to marine traffic. Temporary surge barriers can avoid these disadvantages. This research evaluates three novel temporary barrier concepts: flexible membrane barriers, sinkable floating barriers, and shade curtain barriers. Flexible membrane barriers are self-deploying and permanently located on shore. Buried when not deployed, they rise with rising water due to their buoyancy. Sinkable floating barriers rest on the seabed when not deployed and, when needed, are raised to the surface by pumping air into a tube. Shade curtains are fabric barriers attached to an existing bridge. When not deployed, it is secured to the underside of the bridge deck. In advance of a surge, the fabric curtain is lowered using a sinker-cable system to provide a vertical barrier extending from the bridge deck to the seabed. Hydraulic loads are transmitted from the barrier to the bridge and its foundations, which must be capable of resisting the added loads. This project addresses three key issues related to temporary surge barrier deployment: site conditions for which temporary surge barriers are appropriate, hydraulic loading on the barriers, and structural/geotechnical design considerations for the barriers.]]></description>
      <pubDate>Sat, 31 Jan 2026 11:29:01 GMT</pubDate>
      <guid>https://rip.trb.org/View/2663229</guid>
    </item>
    <item>
      <title>Improving Moisture Resistance/Control of Pavement Foundation Systems via Engineered Water Repellency
</title>
      <link>https://rip.trb.org/View/2659346</link>
      <description><![CDATA[The objective of this project is to evaluate the use of nanoscale organo-silane (OS) to control water and increase subgrade and overall pavement performance. It will also explore the extent to which OS can mitigate frost heave-thaw settlement and thaw weakening of frost susceptible pavement foundation layers. This will be achieved through the completion of four objectives: (1) collect both subgrade soils and OS materials; (2) develop a viable treatment design for field construction; (3) construct test sites with OS and without OS (control) and evaluate their geomechanical (e.g., stiffness, strength, F-T durability) and environmental (e.g., temperature, moisture, and matric suction) performances; and (4) collect data and calibrate numerical models. Advanced technologies provided as a match to the project will be used, including Light Detection and Ranging (LiDAR) and shape array sensors (SAS).]]></description>
      <pubDate>Mon, 26 Jan 2026 16:09:33 GMT</pubDate>
      <guid>https://rip.trb.org/View/2659346</guid>
    </item>
    <item>
      <title>Automating the Lateral Strength Assessment of the American Association of State Highway and Transportation Officials (AASHTO) Standard and Substandard Concrete Barriers</title>
      <link>https://rip.trb.org/View/2655577</link>
      <description><![CDATA[One of the important outcomes of the KTRAN: KSU-21-6 project that concluded in May 2023 is the development of a closed form procedure to assess the ultimate lateral strength of sub-standard concrete barriers using a rigorous yield line analysis beyond the prediction capabilities of the current American Association of State Highway and Transportation Officials (AASHTO) procedure. This method was confirmed by a truss analogy approach and finite element analysis. The closed form equations developed in that project were tedious to carry out by hand or Excel and the establishment of a computer software is deemed to be the most efficient and useful tool to add to the Kansas Department of Transportation (KsDOT)’s assessment capabilities. The findings of the earlier study revealed the fact that the lateral ultimate strength of sub-standard barriers exceed the current strength classification of AASHTO standard barriers leaving the geometrical height of the sub-standard barrier as the only deficiency to overcome in order to make such barriers as good as the standard barriers in mitigating truck crashes. Accordingly, the PI’s are proposing to develop a software package that implements a rigorous yield line analysis procedure incorporating the material-specific properties (steel and concrete) in determining the lateral ultimate strength of barriers. The software will be equally applicable to standard and sub-standard barrier assessments. It is expected to yield a powerful tool that can optimize the strength design of any concrete barrier. This is expected to lead to improvements in both the geometry, concrete and reinforcement properties in realizing an optimum target design. It will also allow examining various types of barrier designs to make the best educated engineering decisions on implementing one type over the other as well as coming up with new designs. 

The specific three main research tasks include: 1) Developing the lateral ultimate strength assessment software for standard and sub-standard barriers; 2) Generalizing the input parameters to explore new barrier geometries; 3) Writing and submitting the final project report and the developed comprehensive software.]]></description>
      <pubDate>Thu, 15 Jan 2026 12:25:04 GMT</pubDate>
      <guid>https://rip.trb.org/View/2655577</guid>
    </item>
    <item>
      <title>Impact of Noise Barriers on Residential Property Values</title>
      <link>https://rip.trb.org/View/2652033</link>
      <description><![CDATA[Highway noise barriers require substantial investment from the Commonwealth of Virginia, yet their effects on nearby residential property values remain uncertain. This study will evaluate the impact of highway noise barriers on residential property values in Virginia, addressing two gaps: (1) reliance on dated Virginia studies, and (2) unclear roles of confounding factors such as school redistricting, crime, interest rates, HOA (homeowner associations and associated amenities), and economic shocks.  The study will deliver Virginia-specific, quantitative evidence on the extent to which noise barriers affect property values.

The study will identify and analyze at least eight matched pairs of neighborhoods (one with a barrier and one without) for the years with available 2012-2024 sales data, with additional pairs included as data availability allows.  If those years are not available, the analysis will focus on the years for which verified sales and barrier data can be obtained.  A regression model will be developed that forecast the log of sales price based on barrier presence or absence plus confounding factors such as home size, type of neighborhood, and time (year and quarter) of sale.  Then, the regression model will be used in two study designs—a cross-sectional analysis and a pre-post analysis.

This study has been requested by Virginia Department of Transportation's (VDOT’s) Environmental Division to support litigation and to improve communication with citizens.
]]></description>
      <pubDate>Fri, 09 Jan 2026 09:12:41 GMT</pubDate>
      <guid>https://rip.trb.org/View/2652033</guid>
    </item>
    <item>
      <title>Develop and Evaluate Long Median Barrier Gate to Assist with Emergency Response</title>
      <link>https://rip.trb.org/View/2636104</link>
      <description><![CDATA[Median barriers are commonly used to separate opposing lanes of traffic on divided highways and to separate managed lanes from general purpose lanes. Concrete Median Barriers (CMBs) are often preferred on urban freeways with narrow medians due to their minimal deflection and low maintenance. However, long, continuous runs of CMBs limit access of emergency and maintenance vehicles to the other side of a roadway or a managed lane. Implementation of crashworthy median barrier gates at these locations can maintain the desired level of median protection for motorists while offering improved cross-median access for emergency and/or maintenance vehicles. The current Texas Department of Transportation's (TxDOT) Barrier Gate (detailed on standard sheet BG-11) is 30-ft long and provides a clear opening of 27 ft between the mounting brackets. For this project, the research team will develop a longer median barrier gate to provide a greater clear opening for larger emergency vehicles and contraflow during evacuation operations. The research team will design the median barrier gate to operate without power and perform crash testing of the median barrier gate to verify compliance with the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH).]]></description>
      <pubDate>Mon, 08 Dec 2025 09:44:38 GMT</pubDate>
      <guid>https://rip.trb.org/View/2636104</guid>
    </item>
    <item>
      <title>High Tension Cable Median Guardrail Expected Lifespan</title>
      <link>https://rip.trb.org/View/2487331</link>
      <description><![CDATA[The Minnesota Department of Transportation (MnDOT) has been installing High Tension Cable Barrier (HTCB) Systems for approximately 20 years along heavily traveled corridors. The objective of this research is to study the lifecycle of HTCB system and the inspection process for this critical safety equipment.]]></description>
      <pubDate>Wed, 08 Oct 2025 09:59:25 GMT</pubDate>
      <guid>https://rip.trb.org/View/2487331</guid>
    </item>
    <item>
      <title>SPR-5010: Feasibility Study of Deploying Movable Barriers as Permanent Barriers and Temporary Traffic Barriers for Future Roadway Design, Construction, and Maintenance</title>
      <link>https://rip.trb.org/View/2601511</link>
      <description><![CDATA[Current highway designs typically rely on permanent barriers to separate lanes and on temporary traffic barriers and traffic control devices to establish work zones. Previous efforts have primarily focused on the safety/cost benefits of movable barriers only in work zones; however, the feasibility of deploying movable barriers as permanent barriers and temporary traffic barriers has yet to be studied through roadway life cycle. This research will conduct a comprehensive comparison to determine whether to adopt movable barriers as replacements/additions in future roadway design, construction, and maintenance.]]></description>
      <pubDate>Thu, 18 Sep 2025 16:09:18 GMT</pubDate>
      <guid>https://rip.trb.org/View/2601511</guid>
    </item>
    <item>
      <title>Design and Safety Considerations of Center Line Barriers</title>
      <link>https://rip.trb.org/View/2558364</link>
      <description><![CDATA[Opposite-direction crashes, which involve a vehicle crossing into opposing lanes and impacting other vehicle(s) head on or in a sideswipe collision, account for more than 5,000 fatalities in the United States each year. These collisions most often occur on two-way, two-lane, high-speed rural roads, where opposing traffic is separated only by a center line pavement marking, sometimes supplemented with rumble strips. This type of roadway comprises approximately 69 percent of the national road network, totaling approximately 1.97 million miles.

NCHRP Research Report 995: Guidelines for Treatments to Mitigate Opposite Direction Crashes outlines several strategies for reducing opposite-direction collisions. Among them are center line buffer areas, which provide additional space between opposing traffic on undivided roads, and cable median barriers installed within the median of divided highways. For highways that do not have a median, a combined approach of installing barrier within a center line buffer area (hereafter referred to as center line barriers) may be effective. Only a limited number of existing sites in the United States have used this approach, and although these installations may not provide the full barrier deflection distance, a 2016 report titled Performance Evaluation of a Cable Median Barrier System on an Oregon Highway with a Narrow Median by Burns and Bell found this treatment effective in reducing opposite-direction crashes. 

Research is needed to evaluate the effects of center line barriers on roadway safety, operations, and maintenance. Additional study is also needed to investigate noteworthy practices and design considerations for implementing this treatment effectively.

OBJECTIVE: The objective of this research is to identify risk factors for opposite-direction crashes and investigate the safety, operational, and maintenance effects of center line barriers on previously undivided roadways. The research results will be used to prepare a guide with noteworthy practices, including safety performance and design considerations.]]></description>
      <pubDate>Thu, 29 May 2025 13:19:57 GMT</pubDate>
      <guid>https://rip.trb.org/View/2558364</guid>
    </item>
    <item>
      <title>Impact Evaluation for Obstacles within Barrier's Working Width


</title>
      <link>https://rip.trb.org/View/2558421</link>
      <description><![CDATA[Barriers deform and deflect when struck by vehicles, so designers provide a clear area behind the barriers to accommodate this movement. The dimensions of this expected deflection zone, referred to as the working width, are typically determined through computer modeling and crash testing under the American Association of State and Highway Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) impact conditions. The working width represents the maximum lateral penetration of either the MASH test vehicle or the barrier beyond the front face of the barrier.

In practice, however, most real-world impacts are less severe than MASH impact conditions and do not require the full working width to shield natural or man-made obstacles behind barriers. Furthermore, site constraints often make it impractical to relocate obstacles outside the working width. Developing a method to measure the potential for impacts with obstacles within a barrier’s working width could help state departments of transportation (DOTs) save both time and project costs.

Research is needed to develop a tool that quantifies the potential of impact(s) with a roadside obstacle based on placement of the obstacle within the working width of the barrier. Such a tool would consider impact conditions, barrier deflection behavior, and obstacle placement within the working width. Characteristics such as obstacle type, barrier length, and average annual daily traffic (AADT) are beyond the scope of this research effort.

The objective of this research is to develop a tool to measure the potential for impacts with obstacles located within a barrier’s working width based on various impact conditions.]]></description>
      <pubDate>Mon, 26 May 2025 21:48:15 GMT</pubDate>
      <guid>https://rip.trb.org/View/2558421</guid>
    </item>
    <item>
      <title>Observation, Documentation, and Performance Evaluation of Bridge Deck using Multi-Crystalline Intermixed Concrete Enhancer and Surface Sealer</title>
      <link>https://rip.trb.org/View/2506091</link>
      <description><![CDATA[Water intrusion on bridge decks leads to degradation of the concrete and reinforcement at an accelerated rate when compared to other concrete bridge components. As an example, freeze/thaw effects can result in delamination or spalling, and chloride ion penetration can result in the material degradation of the concrete and steel reinforcement. Eliminating or reducing water intrusion into the bridge deck concrete has the potential to greatly increase the service life of the bridge deck and, subsequently, the overall bridge.

An admixture product and surface sealer are proposed for use on a bridge construction project in Appanoose County, Iowa. The bridge superstructure will consist of concrete prestressed, precast girders topped by a concrete, steel-reinforced deck. The project presents an opportunity to observe and document the construction and performance of the deck with the inclusion of the moisture prevention products.]]></description>
      <pubDate>Thu, 06 Feb 2025 10:08:41 GMT</pubDate>
      <guid>https://rip.trb.org/View/2506091</guid>
    </item>
    <item>
      <title>Modeling Wolf Creek Pass Combination of Layers of Barriers</title>
      <link>https://rip.trb.org/View/2431164</link>
      <description><![CDATA[In the mountainous regions with rugged terrains like in Colorado and adjacent Rocky Mountain states, having sharp turns of roadways and passes to go around the terrain are common features with inherent extra safety concerns beyond ordinary consideration.  A prominent example is one of spots along Wolf Creek Pass where there were multiple severe or fatal vehicular accidents.   That spot features not only a small radius of turn but also a downward gradient which often leads to speeds higher than the posted speed limit and warning to the incoming vehicles and trucks.   
Despite the fact that numerous safety measures have been installed to warn drivers, in the past couple of years, Wolf Creek Pass has experienced a slight increase in vehicle accidents that have resulted in loss of lives and property damages in this area.  Additional safety measures are therefore required to mitigate the severity of future incidents.
The purpose of this research study is to examine one possible solution that may prevent future loss of lives in this area.  The expected outcomes of this study shall include a development of effective layers of barriers design to reduce the danger of roadway bend conditions such as those at Wolf Creek Pass where accidents can be fatal for heavy vehicles and trucks with a high center of gravity running into it at high speed.  These outcomes shall be achieved by using the advanced 3D nonlinear dynamic computer modeling and analysis of a combination of layers of barriers to absorb, redirect the kinetic energy and stop the momentum of heavy trucks as they approach at high speeds down the slopes toward the bend as well as prevent heavy freight vehicles from flipping over. ]]></description>
      <pubDate>Mon, 16 Sep 2024 08:56:10 GMT</pubDate>
      <guid>https://rip.trb.org/View/2431164</guid>
    </item>
    <item>
      <title>Conduct MASH Test Level 3 (TL-3) Evaluations of Concrete Barriers on Roadside Slopes</title>
      <link>https://rip.trb.org/View/2420100</link>
      <description><![CDATA[Concrete barriers are designed and crash tested for placement on flat terrains. In-field installations of concrete barriers are sometimes placed on slopes adjacent to roadways. By placing the barrier on a slope, the effective height of the barrier that engages an errant vehicle may be reduced since the vehicle may be airborne as it contacts the barrier on a downward slope. Consequently, the barrier may not be able to safely contain and redirect the vehicle. The research team will evaluate the performance of Texas Department of Transportation's (TxDOT's) 32-in tall F-shape and 42-inch tall single slope barrier when placed on roadside or median slopes of up to 4H:1V. The research team will develop guidance for placement of these barriers using finite element simulation analysis and full-scale crash testing. The guidance will determine the maximum allowable slope for each barrier type and any placement offsets required from the edge of the roadway or from the bottom of the ditch. The research team will evaluate the performance of the barriers using impact conditions and evaluation criteria in the Manual for Assessing Safety Hardware (MASH) for Test Level 3 for longitudinal barriers.]]></description>
      <pubDate>Fri, 23 Aug 2024 12:30:34 GMT</pubDate>
      <guid>https://rip.trb.org/View/2420100</guid>
    </item>
    <item>
      <title>Framework for participatory evaluation of greenery screens in
environmental justice communities
</title>
      <link>https://rip.trb.org/View/2420067</link>
      <description><![CDATA[A growing strategy to mitigate environmental harms is the implementation of green infrastructure in
high-pollution zones, such as greenery screens, vegetation barriers, and living walls. This study
synthesizes the outcomes of existing projects and proposes an evaluation framework that centers
community participation. Greenery screens and sound walls are intended to mitigate noise and air
pollution, which can reduce health disparities and improve quality of life in surrounding communities.
Additional co-benefits may be observed when considering the role of this infrastructure during
extreme weather events, such as flooding, extreme heat, and poor air quality from wildfires.
Within the sustainability framework known as the triple bottom line, some studies have begun to
examine the environmental, social, and financial benefits of green infrastructure, but initial findings
on the effectiveness of greenery screens remain inconclusive. Expanding this framework to include
the principles of equitable evaluation, methodological advancements are needed to account not only
for distributional equity, but structural and procedural equity, as well. For example, integrating the
cumulative impact assessments required by the National Environmental Policy Act into the infrastructure evaluation process could be one means of addressing structural equity, and practicing
living labs where community members collect and interpret data from sensors tracking environmental
determinants of health could be a technique to incorporate procedural equity into the evaluation
process. The proposed systematic literature review will result in actionable strategies for working in
collaboration with low-income communities of color who have been disproportionally harmed by
freeway infrastructure to advance environmental justice. Findings from this study will provide
recommendations to policymakers and analysts committed to advancing distributional, structural,
and procedural equity.]]></description>
      <pubDate>Thu, 22 Aug 2024 16:05:52 GMT</pubDate>
      <guid>https://rip.trb.org/View/2420067</guid>
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