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    <title>Research in Progress (RIP)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Research in Progress (RIP)</title>
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      <link>https://rip.trb.org/</link>
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    <item>
      <title>Leveraging Existing Vegetated Roadside Areas for Efficient Stormwater Management</title>
      <link>https://rip.trb.org/View/2726138</link>
      <description><![CDATA[Stormwater runoff from transportation infrastructure presents a persistent challenge for Oregon’s transportation system due to the requirement to treat highway stormwater runoff and protect downstream water quality. Current regulatory requirements compel project teams to demonstrate adequate stormwater treatment and infiltration performance during planning and design. However, limited understanding of how hydrologic data and roadside soil properties influence geochemical treatment capacity often prevents reliable evaluation of whether the natural roadside environment itself can meet objectives, providing an unrealized opportunity for potential savings on unnecessary facility installation and maintenance costs.
OBJECTIVES: The overall objective of this project is to develop and validate an integrated hydrologic-geochemical decision-support tool that enables early-stage screening of existing roadside stormwater infiltration potential and treatment performance. The tool will provide Oregon Department of Transportation (ODOT) with simulation capabilities to predict and quantify surface runoff routing, infiltration capacity, and subsurface geochemical dynamics. The coupled hydrologic-geochemical framework will support quantitative evaluation of whether already existing roadside environments can meet stormwater performance metrics and identify locations where built treatment facilities are actually necessary. 
The project will provide ODOT with quantitative decision-support framework for early-stage screening of roadside stormwater infiltration and treatment feasibility. The framework directly addresses the current uncertainty in determining when existing roadside soils and vegetative cover can meet stormwater performance requirements and when engineered treatment facilities are necessary. By enabling systematic identification of locations where existing soils provide sufficient infiltration and contaminant attenuation, this project may assist with (1) reducing unnecessary engineered stormwater treatment facilities that require construction costs, operational costs and long-term maintenance commitments, and (2) reducing the need to acquire additional ROW to install engineered facilities, minimizing both project delivery and O&M costs. Even if additional ROW may be needed to fit the natural areas for treatment, long-term operation and maintenance costs will likely be reduced.]]></description>
      <pubDate>Wed, 08 Jul 2026 17:25:51 GMT</pubDate>
      <guid>https://rip.trb.org/View/2726138</guid>
    </item>
    <item>
      <title>Improving Stormwater Systems for Debris and Contaminant Capture</title>
      <link>https://rip.trb.org/View/2712206</link>
      <description><![CDATA[Highway runoff carries a complex mix of pollutants, including debris, heavy metals, and nutrients. Oil, grease, and combustion byproducts from vehicles further add to the contaminant load. In addition to these conventional pollutants, scientific advances have highlighted contaminants of emerging concern (CECs) that were not fully recognized when most departments of transportation’s (DOT’s) stormwater programs were first developed.

Unlike conventional pollutants that degrade over time, many of these debris and CECs persist. They clog inlets and ponds, reduce hydraulic conductivity, and increase pollutant loads to downstream waters. For DOTs, this creates two major challenges: rising costs to maintain stormwater assets, and regulatory risk under municipal separate storm sewer system permits if pollutant control cannot be demonstrated.

The objective of this research is to develop a guide for reducing broad pollutants, which include macro-debris, microplastics, and tire wear particles, which have been demonstrated to contain compounds toxic to certain aquatic organisms.]]></description>
      <pubDate>Wed, 10 Jun 2026 11:28:41 GMT</pubDate>
      <guid>https://rip.trb.org/View/2712206</guid>
    </item>
    <item>
      <title>Design of Stormwater BMPs for Surface and Groundwater Protection Based on Site-Scale Soil Properties: Phase II</title>
      <link>https://rip.trb.org/View/2706364</link>
      <description><![CDATA[The objective of this project is to optimize the nitrogen (N) and phosphorus (P) removal potential of stormwater basins by improving the ability to predict the performance of common native soil properties alone, or with a BAM amendment, and using two planting specifications typically utilized in Florida Department of Transportation (FDOT) maintenance. Phase II will build upon the findings of Design of Stormwater BMPs for Surface and Groundwater Protection Based on Site-Scale Soil Properties: Phase I BDV24-977-43 (hereafter referred to as “Phase I”), which demonstrated the superior performance of unamended native soils with moderate soil organic matter and clay contents in the removal and sequestration of N and P during short-term laboratory experiments. Specifically, the research team will leverage this knowledge in a new experiment with improved external validity through the use of outdoor mesocosms in a multi-year study (e.g., scaling-up in both space and time). Commonly encountered native Florida soils will be prepared and planted per FDOT specification in replicated stock tanks (e.g., ~300-500 gal), with or without a BAM blanket filter, and using at least two FDOT approved vegetative strategies. Inflow and outflow hydrology will be controlled to mimic wet and dry basin hydropatterns and real-time mass balance of nutrient transport/transformation. The plant-soil-microbial interactions will be investigated to determine optimal N and P removal rates under varied hydrology. This new empirical data will improve stormwater BMPs by more accurately assessing the potential of native site soils, planting, and amendment strategies to function in nutrient remediation at the project site scale.]]></description>
      <pubDate>Wed, 27 May 2026 10:39:28 GMT</pubDate>
      <guid>https://rip.trb.org/View/2706364</guid>
    </item>
    <item>
      <title>Quantifying the Flood Resilience Value of Water Quality Best Management Practices on Vermont Roads</title>
      <link>https://rip.trb.org/View/2689762</link>
      <description><![CDATA[Transportation networks have been recognized as contributors to water quality impairment by discharging stormwater, sediment, and nutrients to receiving waters. These contributions can occur through chronic inputs of water and pollutants washed from the road surface during storm events or through episodic and often catastrophic road failure by mass wasting or fluvial erosion at structure crossings during extreme storms. Research studies in forested areas of the eastern United States, and elsewhere, including those conducted by members of this project team, have documented rates of erosion and mass wasting from low volume roads and impacts on water quality. Our previous research has also documented the importance of unpaved roads on water quality impairment and quantified the effectiveness of best management practices (BMPs) in reducing sediment and phosphorus contributions.
The Phosphorus Total Maximum Daily Load for Vermont Segments of Lake Champlain (a.k.a. TMDL) called for reductions in phosphorus contributions from developed lands, motivating a need to address stormwater runoff from the state’s transportation network. Statewide efforts to achieve the reductions required by the TMDL led to the development of the Municipal Roads General Permit (MRGP) in 2018 and subsequent revisions. Recent extreme flooding events across the state, in particular the July 10-11, 2023 North Country Storm event and associated Great Vermont Flood which will be the focus of this project, in addition to subsequent flood events in December 2023 and July 2024, have resulted in the need for emergency repairs of damaged transportation infrastructure, and revealed the need to clearly communicate the cost benefit of improved stormwater management on the transportation network. In past research projects funded by the Vermont Department of Environmental Conservation and the Vermont Agency of Transportation, we conducted retrospective analyses (i.e. a review of project planning documents and site visits to assess existing conditions) of transportation stormwater upgrades funded by the state’s Better Roads and Grants in Aid programs and found that the BMPs installed through these grants were highly robust to extreme flood events. This project therefore aims to expand on the research teams’ prior work to assess the life cycle cost-benefit of BMP adoption with a focus on the BMPs required by the Municipal General Roads Permit (MRGP), Sections 1 and 2 of the VT Road and Bridge Standards for municipal roads, and VTrans Drainage Management Standards for State roads. The data and results of this project may be used to update VT AOT’s Transportation Resilience Planning Tool or other mitigation practices.
To facilitate this work, we will form a technical advisory committee (TAC) composed of VTrans project champions (Todd Eaton), Vermont Department of Environmental Conservation (VT DEC) staff engaged in the implementation of the Municipal Roads General Permit, members of at least one Regional Planning Commission, and others identified by VTtrans. The role of the TAC will be to help guide study design, facilitate the use of existing data, leverage on-going implementation of erosion control projects, and provide context for agency needs.]]></description>
      <pubDate>Wed, 08 Apr 2026 09:46:01 GMT</pubDate>
      <guid>https://rip.trb.org/View/2689762</guid>
    </item>
    <item>
      <title>Improved VDOT Bioretention Media Specification</title>
      <link>https://rip.trb.org/View/2672501</link>
      <description><![CDATA[Virginia Department of Transportation (VDOT) uses bioretention as a stormwater control measure (SCM); however, the most recent special provision for VDOT bioretention soil media requires that testing the media’s infiltration rate use a unique mesocosm test method, outlined in VTM-134 (VDOT, 2025), which presents five challenges.  These are (1) inconsistency in how the media is placed and ultimately compacted in the test apparatus and therefore potential variability in the test results; (2) lack of labs willing to run the mesocosm test (only one in Virginia does this); (3) large amount of media required (40 5-gallon buckets of media and related materials); (4) lack of information proving this test is needed to procure successful bioretention soil media; and (5) a cost of $6,000 to run one test.  Due to these challenges, few media providers both try to meet the requirements and then succeed in doing so, which ultimately increases the overall project costs when bioretention is selected as the SCM.  A unique aspect of testing a media’s infiltration rate using the mesocosm test is consideration of how both de-icing salts and wet and dry cycles (to mimic rainfall patterns) impact a media’s infiltration rate. These unique aspects of the mesocosm test appear to be why it’s included in the current special provision. This study will recommend a specification for VDOT bioretention soil media that addresses the five challenges of the mesocosm test method to determine the media’s infiltration rate based on laboratory testing.]]></description>
      <pubDate>Thu, 19 Feb 2026 10:50:44 GMT</pubDate>
      <guid>https://rip.trb.org/View/2672501</guid>
    </item>
    <item>
      <title>Innovative Stormwater Solutions for Linear Projects</title>
      <link>https://rip.trb.org/View/2486932</link>
      <description><![CDATA[Managing stormwater is a critical part of any transportation infrastructure project, both during construction and long term. Meeting water quality requirements during long linear projects is challenging given limited right of way and resources; this is especially true in tight urban areas. The increase in impervious surfaces has increased the amount of water that must be managed (as opposed to being absorbed into the ground). There are different types of challenges managing stormwater within urban and rural areas, each require different approaches and techniques. For each, the creation and maintenance of stormwater infrastructure have different implications for roadside infrastructure and vegetation. Finally, there are multiple different challenges that occur at different timeframes, from short term construction challenges to longer term infrastructure and maintenance concerns.]]></description>
      <pubDate>Wed, 08 Oct 2025 10:14:01 GMT</pubDate>
      <guid>https://rip.trb.org/View/2486932</guid>
    </item>
    <item>
      <title>A Multi-Criteria Framework for Selecting Nature-Based Solutions for Remnant Properties for Regulatory Credit</title>
      <link>https://rip.trb.org/View/2604609</link>
      <description><![CDATA[The primary objective of this research is to develop and implement a robust multi-criteria decision support framework to enable the North Carolina Department of Transportation (NCDOT) to strategically leverage remnant properties as nature-based solutions for regulatory credit under the Department’s statewide National Pollutant Discharge Elimination System (NPDES) stormwater permit (NCS000250) and under state nutrient management strategy rules. In recent years NCDOT has experienced a significant escalation in construction costs, including costs associated with designing and constructing stormwater control measures along existing highways as is required by Section 3.6.1 of the NPDES stormwater permit and 15A NCAC 02B .0281 (9)(d) of the Falls Lake nutrient management strategy rules. In an effort to control construction and long-term maintenance costs, NCDOT piloted a project to retain ownership of four adjacent remnant parcels in Division 5 (Falls Lake watershed) and quantify the stormwater management benefits of maintaining the parcels in an undeveloped land cover. The NC Department of Environmental Quality formally recognizes land conservation as a creditable compliance practice and NCDOT demonstrated that the pilot project saved the Department $3,500,000 in avoided design, construction, and long-term maintenance costs of stormwater infrastructure relative to the value of the properties if sold on the open market. The success of the pilot project in Division 5 has demonstrated that remnant properties from right-of-way acquisitions provide a unique opportunity to provide a value-added repurposing of underutilized assets. The aim of this framework is to align NCDOT's stormwater management compliance obligations with the untapped potential of remnant properties by achieving regulatory compliance, environmental sustainability, cost-effectiveness, social impact, and asset optimization through the strategic deployment of nature-based solutions (NBS).
To achieve this objective, the research begins with a systematic literature review, identifying best practices and relevant frameworks in stormwater management and NBS. The research team will then conduct expert interviews and surveys to engage NBS experts and practitioners. Next, the team will conduct outreach activities to engage NCDOT stakeholders, ensuring their valuable input is incorporated into the decision-making process. Then the team will collate the knowledge gained in these tasks to develop an adaptable, data-driven decision support framework. Lastly, the team will use the newly developed framework to conduct real-world case studies that will test the framework's efficacy, including sensitivity analysis to ensure robustness and flexibility. By combining scientific rigor, expert input, stakeholder engagement, and practical application, the research approach aims to produce a tool bridges the gap between sustainability and effective stormwater management.
This research holds significant importance for both NCDOT and the broader community. It positions NCDOT as a leader in sustainable stormwater management, leveraging remnant properties to reduce costs, enhance environmental stewardship, engage communities, and meet regulatory obligations. Anticipated outcomes include a versatile decision support tool that can be adapted for various scenarios, insights from case studies that provide real-world applicability, and sensitivity analysis results to ensure the framework's robustness. Ultimately, the research empowers NCDOT to make informed decisions that benefit economic efficiency, ecological health, and social well-being in the realm of stormwater management, setting a precedent for sustainable practices in transportation agencies.]]></description>
      <pubDate>Tue, 30 Sep 2025 14:04:14 GMT</pubDate>
      <guid>https://rip.trb.org/View/2604609</guid>
    </item>
    <item>
      <title>Traversable Postconstruction Stormwater Check Dams in Clear Zones


</title>
      <link>https://rip.trb.org/View/2558390</link>
      <description><![CDATA[State departments of transportation (DOTs) must comply with stormwater discharge requirements under the Clean Water Act. Clear zones within the highway right-of-way often provide suitable locations for stormwater management close to the source of runoff. Roadway swales with check dams are a common, cost-effective solution for stormwater quantity and quality control in these clear zones. 

Current guidelines do not provide recommendations for the design of check dams in clear zones. Additionally, check dam design must be compatible with the primary purpose of clear zones: vehicular safety. Concerns have been raised about check dams causing vehicles to vault into oncoming traffic or rollovers. Research is needed to support the development of check dam design specifications that meet state DOT safety requirements and to help achieve water quality goals.

The objective of this research is to develop a guide and accompanying site assessment decision support tool for designing traversable postconstruction check dams in clear zones. ]]></description>
      <pubDate>Wed, 28 May 2025 13:28:45 GMT</pubDate>
      <guid>https://rip.trb.org/View/2558390</guid>
    </item>
    <item>
      <title>Quantitative Study of Environmental Condition and PFAS Impacts on Microplastic (MP) Fate and Transport due to Effects on MP Flocculation</title>
      <link>https://rip.trb.org/View/2442011</link>
      <description><![CDATA[Microplastics (MPs) are a class of emerging contaminants of concern that result from the degradation products of plastic-based fibers, particles, and films. Transportation related pollution contributes notably to MP pollution in the environment, particularly in urban areas where pollutants such as anthropogenic debris and tire wear particles are exported to rivers and streams through urban stormwater and roadway runoff. Moreover, MPs are increasingly found in drinking water and drinking water sources, which may contribute to disproportionate impacts on communities of concern located near urban areas. Despite the abundance of MPs and their impacts to health and the environment, there are currently notable knowledge gaps related to MP fate and transport processes. Addressing these knowledge gaps is needed to support the design of approaches for mitigating transportation related MP pollution through improved process-based understanding. 
	The focus of this project is specifically on the process of MP flocculation, or aggregation, with other MPs and/or other nearby materials occurring in the surface water environment. Figure 1 conceptually illustrates the transport of MP pollution from transportation related sources and through surface waters. MPs will settle to the sediment bed at different rates depending on their settling velocity, which can be notably impacted by the flocculation of MPs with other material (e.g., sediment, organic material) into larger composite particles known as “flocs”. The flocculation process can increase settling velocities and even cause otherwise buoyant MPs to settle. While the process of MP flocculation has been highlighted in recent studies, quantitative understanding of the impacts of environmental parameters (e.g., suspended sediment, salinity) on MP flocculation are lacking. In addition, the potential impacts of chemicals of concern, such as per- and polyfluoroalkyl substances (PFAS), on the MP flocculation process has not been investigated. Hydrophobicity and surface chemistry affect flocculation processes as MPs interact with nearby material and may be further impacted by PFAS sorption to MP surfaces. This project will experimentally examine the effects of environmental conditions PFAS on MP floc sizes and settling velocities by using an imaging-based MP floc measurement system. These results will provide new quantitative information about MP fate and transport that can be used in future modeling efforts and to inform design of pollution mitigation strategies.

US DOT Priorities: This project is an investment in fundamental research that advances basic understanding of microplastics transport from transportation related pollution sources, through rivers and streams, and to potential accumulation zones. This work addresses critical needs for improved quantitative understanding of MP transport mechanics and supports future modeling efforts for MP fate. Settling velocity is a critical input parameter in these models and uncertainty concerning MP floc formation notably hinders current prediction accuracy. Through the impacts of this research on future modeling of MP pollution in the environment and of the effectiveness of mitigation strategies, this work supports the USDOT Strategic Goals for “Transformation” and “Climate and Sustainability.” Addressing MP pollution in surface water and stormwater is also important for community health since MPs are increasingly found in drinking water and drinking water sources. Since MP pollution tends to be highest near urban areas, addressing these issues is a matter of concern for equity since nearby communities of concern in densely populated urban areas may be disproportionately affected by MPs. The improved understanding of MP pollutant transport provided here will thus support the strategic goal for “Safety” and “Equity” by informing pollution mitigation strategies.

Outputs: This project will result in new quantitative data that provides insight about fate and transport mechanics of MPs that are input to the environment via transportation related pollution. The datasets will quantify reference settling velocities for isolated MPs. The datasets will also quantify the effects of environmental conditions and the presence of PFAS on MP flocculation and settling velocity. Quantification of these effects is limited in the literature. This dataset will enable future modeling of MP transport with evidence-based consideration of processes and environmental factors that may drive MP settling and accumulation in the sediment beds of inland, estuarine, and marine waters. Additionally, a white paper will be produced to present correlations between PFAS adsorption and MP transport based on the study results. 

Outcomes/Impacts: By advancing the quantitative accuracy of MP transport modeling efforts, this work will support informed design of microplastic mitigation strategies that can preserve environmental resources and improve the sustainability of transportation infrastructure designs. Moreover, this work can enable evidence-based cost-benefit assessment of various pollution mitigation designs used to mitigate transportation related microplastic pollution. This type of MP transport modeling can be used to assess the risks associated with a continuation of “business as usual” practice and support future regulatory and policy decisions concerning the mitigation of MP pollution, particularly in urban environments. This project will also inform regulations focused on multiple environmental contaminants, namely MPs and PFAS, which are both emerging contaminants of concern that may affect both environmental and public health. 
]]></description>
      <pubDate>Thu, 17 Oct 2024 11:04:32 GMT</pubDate>
      <guid>https://rip.trb.org/View/2442011</guid>
    </item>
    <item>
      <title>ACRP First Look: Understanding Impacts of Tire Anti-degradants 6PPD and 6PPD-Quinone at Airports



</title>
      <link>https://rip.trb.org/View/2413907</link>
      <description><![CDATA[The Airport Cooperative Research Program (ACRP) has solicited letters of interest from researchers to produce a white paper, known as an ACRP First Look, on tire anti-degradants 6PPD and 6PPS-quinone (6PPD-q) and their potential impacts on airports.
ACRP is a contract research program that develops near-term, practical solutions to problems facing airport-operating agencies. It is sponsored by the Federal Aviation Administration and managed by the National Academies of Sciences, Engineering, and Medicine through the Transportation Research Board. Program oversight and governance are provided by representatives of airport-operating agencies and others appointed to the ACRP Oversight Committee by the U.S. Secretary of Transportation. 
ACRP recognizes that some topics are so new, or are evolving so quickly, that they may not be suitable for a traditional research effort. In these instances, ACRP uses an abbreviated research process to develop an ACRP First Look (typically 50 pages or fewer). ACRP First Looks provide the airport industry with context on quickly developing topics in a timely manner, typically within 6 months.
Attention has recently focused on 6PPD and its formation product 6PPD-q since it has been linked to the mortality of select fish species in North American streams. 6PPD is an anti-degradant added to tires to prevent them from breaking down and helps them last longer. However, throughout the life of the tire, friction causes tire wear particles to be released into the environment. The 6PPD and 6PPD-q included in these tire wear particles are released to the atmosphere and roadways, where they enter bodies of water through surface runoff. Attention to the occurrence, fate, and transport of 6PPD and 6PPD-q to date has primarily focused on roadway impacts from cars and trucks. However, as these tire anti-degradants also are added to aircraft tires and the tires of ground service equipment operating at airports, they are expected to be present in stormwater runoff from airports. Furthermore, rubber from tires has frequently been identified in foreign object debris collected from impervious surfaces at airports, such as runways, taxiways, and aprons. Yet little focus has been on the prevalence and impacts of 6PPD and 6PPD-q and their sources at airports. The U.S. Environmental Protection Agency is currently developing a testing method for 6PPD-q, and regulations are anticipated in the near term, which could affect the management of stormwater and other media at airports. However, the scale of the potential impacts, technical challenges, and research needs that airport managers may face in monitoring and responding to 6PPD and 6PPD-q have not been fully explored.
OBJECTIVE: The objective of this research is to prepare an ACRP First Look that provides an overview of anti-tire degradants and their nexus with airports, including issues, potential challenges and opportunities, regulatory and legal context, and future needed research.

]]></description>
      <pubDate>Mon, 05 Aug 2024 20:03:54 GMT</pubDate>
      <guid>https://rip.trb.org/View/2413907</guid>
    </item>
    <item>
      <title>Assessing Effectiveness of Pond Sediment Removal for Phosphorus Management in Stormwater Ponds</title>
      <link>https://rip.trb.org/View/2387527</link>
      <description><![CDATA[Stormwater ponds are plentiful in Minnesota and can be useful in treating stormwater runoff. Some ponds, however, can re-release phosphorus. This project will investigate the effectiveness of sediment removal in improving stormwater quality and reducing phosphorus downstream. It will also explore if sediment should be treated to reduce phosphorus release during dredging.]]></description>
      <pubDate>Fri, 07 Jun 2024 09:25:26 GMT</pubDate>
      <guid>https://rip.trb.org/View/2387527</guid>
    </item>
    <item>
      <title>Field and Laboratory Evaluation of Roadside Soil Quality Restoration Practices</title>
      <link>https://rip.trb.org/View/2344961</link>
      <description><![CDATA[Stormwater control measures (SCMs) are important to mitigate the stormwater quantity and quality of land development on roadsides. Runoff from impervious pavement surfaces creates a substantial disturbance to natural hydrologic processes. Many options are available to manage stormwater on roadsides including detention basins, bioretention basins, and permeable pavements. However, these structural-based practices are costly to build and maintain. An alternative cost-effective SCM is to restore the quality of the existing roadside topsoil. In the proposed study, various cost-effective soil quality restoration treatments will be evaluated to effectively manage stormwater runoff on roadsides. The main goal of this research project is to quantify the improvements for vegetation establishment and subsequent stormwater volume reduction by the proposed soil quality restoration treatments. The research methodology involves conducting both field and greenhouse experiments to determine the selection and mixing ratios of different cost-effective additives such as composts, proprietary soil amendments, and biochars for rapid restoration of roadside soil quality. This work will also investigate the impact of soil compaction and tillage effects on roadside soil quality restoration. Primary tasks for the project will be the development of a specification and implementable guidance for these restoration techniques. The objectives will be achieved in six phases: (1) review of current Iowa DOT practices; (2) collection and determination of the physicochemical properties of the soils and additives mentioned above; (3) greenhouse study; (4) construction and monitoring of field plots; (5) cost analyses; and (6) development of an implementable guideline to help in the selection of the proper additive materials and mixing ratios, and construction and maintenance methods (e.g., mower type and mowing frequency) for roadside soil quality restoration in terms of performance and cost-benefit. The outcome of this research in the form of a construction guideline and a design specification could be immediately implemented by Iowa DOT.
]]></description>
      <pubDate>Tue, 27 Feb 2024 19:29:09 GMT</pubDate>
      <guid>https://rip.trb.org/View/2344961</guid>
    </item>
    <item>
      <title>Stormwater Management to Address Highway Runoff Toxicity Due to 6PPD-Quinone from Tire Rubber</title>
      <link>https://rip.trb.org/View/2265694</link>
      <description><![CDATA[The current method for extending tire longevity by preventing tire-rubber cracking and degradation includes the addition of the chemical additive 6PPD. With tire wear and atmospheric ozone exposure 6PPD oxidizes to form 6PPD-quinone (6PPD-q). Recent research has demonstrated toxicity of 6PPD-q for at least one Endangered Species Act listed aquatic threatened and endangered species, coho salmon, with potential for toxic impacts to other aquatic species, including rainbow trout/steelhead and brook trout. These findings will likely result in regulatory agencies imposing stormwater treatment requirements for 6PPD-q on highway projects as well as raising questions regarding state DOTs’ use of pavements containing recycled-tire-rubber materials. This research aims to equip state departments of transportation (DOTs) with a targeted approach for effectively managing 6PPD-q in highway runoff by (1) developing methods/criteria for identifying locations that need focused treatment, (2) developing a better understanding of the fate and transport of 6PPD and 6PPD-q, (3) developing cost-effective design guidance for stormwater treatment and management techniques with a focus on reducing the effects of 6PPD-q on receiving waters, and (4) evaluating the degree of 6PPD-q release from pavement products made from recycled tire materials. This research will also assist with providing regulatory agencies with a better understanding of DOT management options including the feasibility, limitations, and effectiveness of treatment methods.]]></description>
      <pubDate>Tue, 10 Oct 2023 15:32:54 GMT</pubDate>
      <guid>https://rip.trb.org/View/2265694</guid>
    </item>
    <item>
      <title>An AI Powered Remote Sensing Framework for Monitoring and Predicting Roadside Water Quality</title>
      <link>https://rip.trb.org/View/2263583</link>
      <description><![CDATA[Project Description: While air pollution is the most visible environmental impact of transportation systems, water pollution and quality issues are also of great importance in the transportation and environment nexus. Specifically, transportation systems can affect water quality directly in many ways, including stormwater runoff, deicing chemicals, vehicle exhaust, oil spills, and other pollutants. However, the impact of transportation systems on water qualify is not well studied or fully understood. A significant challenge is the slow movement of ground water through aquifers and its long-lasting, detrimental effects on communities, aquatic life, and the overall health of the ecosystem. Addressing this challenge requires continuous and reliable data collection, as well as advanced data analytics techniques. The traditional method of manual data sampling and analysis is not sufficient. In this project, we will design and develop an AI powered remote sensing framework and associated algorithm for roadside water quality monitoring and prediction, as well as algorithms for causality analysis based on long-term historical data. It has been shown that remote sensing systems can be used to monitor water quality issues, and causality analytics is an effective approach to derive environmental impacts in long term. By leveraging the state-of-the-art technologies in distributed sensing, AI and big data analytics, the proposed research provides great potentials for water quality monitoring and causality discovery, leading to a better understanding of the long-term environmental impact of transportation systems.

US DOT Priorities: This project directly addresses DOT’s research priority of “Preserving the Environment” by developing novel tools and technologies to discover causal relations between the water pollution and transportation systems, leading to effective mitigation strategies to address the water quality challenges. 

Outputs: The proposed research will produce a robust remote sensing and data analytics framework for monitoring and predicting the water pollution caused by transportation systems. The novelty of the research is that it will incorporate causality analytics to learn the long-term effects of the water pollution. Figure 1 shows the system architecture and the proposed workflow. The outputs include integrated hardware and software framework, as well as causality analysis results on both the collected data and the historic data. The project will also produce publications, presentations, and technical reports.

Outcomes/Impacts: The project will produce new knowledge on the environmental impacts of transportation systems, as well as the causal relations. These findings will provide policy makers the rich information they need for making informative decisions on transportation systems design and operations. In addition, by utilizing data from different domains, the project will provide insight on effective and efficient data sharing, which is critical for the community. To further broadening participation, we will involve undergraduate students, and students in underrepresented groups in the research.]]></description>
      <pubDate>Mon, 09 Oct 2023 14:18:39 GMT</pubDate>
      <guid>https://rip.trb.org/View/2263583</guid>
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      <title>Water quality monitoring network to assess downstream efficacy of green infrastructure and provenance of non-point source pollutants</title>
      <link>https://rip.trb.org/View/2264209</link>
      <description><![CDATA[The research team proposes to establish a water quantity and water quality monitoring network that can be leveraged to evaluate the efficacy of green infrastructure to reduce runoff volumes and identify the provenance of non-point source pollutants in downstream water bodies.
In urban settings, rivers and streams are frequently afflicted by the so-called “urban stream syndrome,” which results from hydraulic alteration of stream channels, increased runoff from impervious areas, non-point source pollution, and modification to the lateral connectivity of the stream to its hillslopes. Urban streams are frequently classified as “flashy,” meaning that transport of water, sediment, other non-point source pollutants occur in brief, yet powerful pulses. This results in a stream system that simultaneously delivers increased discharge and non-point source pollutants during storms, but rapidly dries during recession periods. This has implications for both freshwater ecosystems and water-related infrastructure. 

One approach to combat the urban stream syndrome includes the application of green infrastructure in disturbed landscapes and investigation of the provenance of non-point source pollutants. To evaluate the performance of green infrastructure, extensive in situ monitoring equipment is commonly used on site. While such monitoring indicates that green infrastructure indeed improves on-site water quantity and water quality, a pressing need exists to evaluate the efficacy of green infrastructure to mediate water quantity (including streamflow permanence) and water quality in downstream waterways. Furthermore, the extent to which the effects of green infrastructure perpetuate to downstream water bodies is currently unknown.
The team proposes to establish a water quality and water quantity monitoring network to evaluate the downstream impacts of green infrastructure on water bodies and identify the provenance of non-point source pollutants. The monitoring network will consist of state-of-the-art, multi-parameter water quality and water quantity platforms. Parameters monitored at the platforms will include discharge, pH, dissolved oxygen, conductivity, temperature, turbidity, NO3-, and streamflow presence/absence. Readings will be recorded every 15-minutes. 
The Middle Fork of Beargrass Creek, located within Louisville, KY, will be the testbed to evaluate downstream impacts of green infrastructure. 84% of the Middle Fork of Beargrass Creek is classified as “developed”, and a federal consent decree to reduce combined sewer overflows in Beargrass Creek is currently enacted.
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      <pubDate>Fri, 06 Oct 2023 19:11:25 GMT</pubDate>
      <guid>https://rip.trb.org/View/2264209</guid>
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