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    <title>Transport Research International Documentation (TRID)</title>
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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>Development of a Novel Trash Capture Device for Highway Environments</title>
      <link>https://trid.trb.org/View/2606252</link>
      <description><![CDATA[Traditional trash capture devices that can be installed in upstream locations such as storm drains or curb inlets are of limited use in highway environments due to potential flooding, hydroplaning, safety, and maintenance-personnel exposure issues. There is a need for a trash capture system that can be retrofitted easily into existing highway drainage infrastructure or included in newer projects. To address this issue proactively, the California Department of Transportation (Caltrans) Division of Environmental Analysis (DEA) initiated a trash capture device development and testing project in early 2020. The DEA Stormwater staff developed the initial idea for a capture housing device. Computational fluid dynamics modeling was used first to assess the feasibility and performance. Next, the hydraulic capacity, trash capture characteristics, operation, and ease of maintenance were tested using a full-scale physical model. After successful testing, standard plans and design guidance were developed. The full-scale model physical test demonstrated the following: (1) the device can pass the 1-year, 1-h storm intensity specified in the regulations without overflowing or causing roadway flooding; (2) the device can pass the 25-year 5-min-duration return period storm drain system design storm event without causing roadway flooding; (3) the device will trap trash sizes of 5 mm or larger for the 1 year, 1-h storm intensity specified in the regulations; and (4) the device has the storage capacity for the quantity of trash generated from a typical 0.405 ha (1-acre) highway drainage area.]]></description>
      <pubDate>Fri, 09 Jan 2026 16:25:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2606252</guid>
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    <item>
      <title>Guide for Culvert and Storm Drain Rehabilitation

</title>
      <link>https://trid.trb.org/View/2558411</link>
      <description><![CDATA[Culvert and storm drain systems constitute critical nodes in U.S. transportation networks; however, many of these structures have met or exceeded their design service life. Replacing culverts under difficult constraints (i.e., high fills, high-volume roadways, difficult maintenance of traffic conditions) presents unique challenges causing transportation agencies to explore rehabilitation options. Much of the maintenance and restoration performed on buried structures is based on past practices and procedures in which state departments of transportation (DOTs) are familiar and experienced with implementing. 

Many times, standardized guidance for the rehabilitation design process is local. Meanwhile, new rehabilitation technologies continue to emerge without sufficient information on when and how they should be applied. The recent American Association of State Highway and Transportation Officials (AASHTO) Culvert and Storm Drain System Inspection Guide (CSDSIG) published in 2020 provides a roadmap for the inventory and inspection of culverts and storm drains. The next logical step is to determine a course of action for assets identified as deficient.  Research is needed to develop strategies for state DOTs on when to replace versus rehabilitate and the choice of a rehabilitation method.

OBJECTIVE: The objective of this project is to develop a guide for state DOTs for evaluating when to either replace or rehabilitate culverts and storm drains. The guide will also assist designers in the selection of the most appropriate rehabilitation method(s) along with the applicable loading conditions and design method to use when applying the chosen method. ]]></description>
      <pubDate>Tue, 27 May 2025 20:50:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/2558411</guid>
    </item>
    <item>
      <title>Improving Culvert Performance with Diffusers and Energy Dissipators</title>
      <link>https://trid.trb.org/View/2558375</link>
      <description><![CDATA[Culvert and stormwater outfall performance presents challenges for hydraulic practitioners. Two challenges often encountered with culvert performance are inadequate capacity under outlet control and excessive energy at the downstream end of stormwater outfalls under inlet control. 

Previous research and applications have demonstrated that diffuser systems are a practicable option for increasing culvert and stormwater outfall capacity (see Special Note B). However, diffuser systems are an emerging technology, and additional methods and application guidelines are needed to support effective design and implementation. 

Current energy dissipator designs often result in large structures that are costly to construct and may require additional right-of-way. There is a need for design approaches that support more compact energy dissipator systems suitable for constrained right-of-way environments. It is important that such systems be adaptable for retrofitting existing culverts to mitigate scour issues. Advancements in computational fluid dynamics (CFD) modeling allow for efficient comparisons between initial prototype designs, saving time and money on physical modeling.

Research is needed to provide hydraulic practitioners with a design and application guide for implementing (1) diffuser systems to increase capacity, and (2) compact energy dissipator systems for retrofitting culverts. 

OBJECTIVE: The objective of this research is to develop a guide for the design and application of culvert diffuser and compact energy dissipator systems. The guide will give hydraulic practitioners the methods needed to deploy these systems in new and retrofit projects. ]]></description>
      <pubDate>Thu, 29 May 2025 12:56:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2558375</guid>
    </item>
    <item>
      <title>Characterization of Sediment Loads and Size Distributions in Nebraska Roadway Runoff - Phase 2</title>
      <link>https://trid.trb.org/View/2507239</link>
      <description><![CDATA[The goal of this project is to expand current research of sediment runoff (both concentrations and size distributions) from roadways to include data from additional districts and Municipal Separate Storm Sewer System (MS4) communities. The additional data will aid in more effective design of sediment removal systems so that installation and maintenance costs can be optimized. Because the design of inline sediment removal systems requires detailed information about sediment sizes and quantities, collection of data from four additional locations will improve the reliability of system installations so that they function well for MS4 communities in parts of the state that are distinct from those sampled during the initial project.]]></description>
      <pubDate>Mon, 10 Feb 2025 11:14:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/2507239</guid>
    </item>
    <item>
      <title>The Evolution of Watertight Storm Drainage Systems</title>
      <link>https://trid.trb.org/View/2218592</link>
      <description><![CDATA[Watertight pipe and structures have historically only been considered with sanitary systems. The cost, however, of construction, maintenance, roadway safety and stream and groundwater contamination have united previous construction industry adversaries. Federal, state and municipal agencies, contractors, pipe and precast concrete producers, and design engineers all want watertight storm drainage systems. The reasons may vary but their overall goal in the same. Government agencies are having significant problems with non-point stream pollution, groundwater contamination, and de-watering of wet lands via leaking storm drainage systems. These agencies are starting to institute regulations to address these problems with possible ramifications on project designs. State DOTs and municipalities are implementing new specifications to address the effects of underground structural failures related to the leaking and piping of backfill materials through open. Contractor's, for their part, are also investigating the cost savings associated with quicker and lower priced watertight construction techniques. The final advocating group, the concrete precaster, is arguing for the benefit of a higher precast quality watertight product, over cast-in-place structures, with no additional cost to the owner. Specific examples from federal agencies, DOT's and cities indicate there is an evolution to watertight storm drainage systems. Financial arguments from the consulting engineers, contractors and precasters point of view demonstrate an alternate reasoning for this requirement. It appears the crest of a new design philosophy regarding storm drainage systems is emerging.]]></description>
      <pubDate>Wed, 18 Dec 2024 13:29:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/2218592</guid>
    </item>
    <item>
      <title>Historic Development Adds Challenge to Storm Drain Tunnel under Railroad</title>
      <link>https://trid.trb.org/View/2218212</link>
      <description><![CDATA[Denver Water is upgrading an existing 24-inch storm drain to a new 42-inch diameter storm drain to improve drainage from their West Side Complex to the South Platte River. The 1,665 foot pipe includes two tunnel crossings under a railroad and Interstate 25 as well as through fill soil potentially contaminated with radium. Historical research revealed that in the late 19th century, a portion of the proposed alignment was a tailrace channel for a pump house on the shore of historic Lake Archer. During the subsurface exploration, the authors discovered that the now buried abutments of a railroad bridge that used to cross the tailrace still exist and create a very tight usable corridor for the alignment of the pipeline through the existing railroad right-of-way. Other challenges to design of the tunneled and open cut sections of the pipeline related to the long history of development in the area include radioactive and hydrocarbon contamination, shallow bedrock and groundwater, loose sands, and historic construction debris in the fill. Pipe ramming was finally recommended as the preferred tunnel construction method to provide the best chance of success for placement of the pipeline under the existing railroad tracks.]]></description>
      <pubDate>Tue, 27 Aug 2024 14:09:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2218212</guid>
    </item>
    <item>
      <title>Integrated Decision-Support Framework for Municipal Infrastructure Asset</title>
      <link>https://trid.trb.org/View/2218178</link>
      <description><![CDATA[Integration planning of infrastructure systems reveals challenging decisions facing Canadian municipalities for planning repair/renewal of road network, water distribution network, and wastewater distribution network. Decision-making for these networks requires the incorporation of a massive amount of data collection, building business processes, identifying decision variables and optimization. The objective of this research is to establish a methodology to facilitate a decision making process that ensures reliable and optimum decisions regarding corridor rehabilitation for road, water and wastewater network. This proposed framework employs the following tasks: (1) analyze risk; (2) conduct performance evaluation; (3) assess the current physical condition of the pipe and road segment; (4) collect data and perform data gap analysis; (5) document conceptual business process diagrams; (6) develop decision analysis trees; and (7) implement optimization of repair/renewal cost and define the best replacement interval via genetic algorithm (GA). In order to demonstrate the model features, a case study has been utilized from the City of Guelph, ON, Canada. The model is developed via genetic algorithm (GA) using GIS platform. The results assist in setting priorities for integrated corridor rehabilitation and is anticipated to generate a capital planning program for the city's infrastructure. In conclusion, this framework helps Canadian municipalities evaluate and select feasible optimal assets for integrated corridor rehabilitation.]]></description>
      <pubDate>Tue, 27 Aug 2024 14:09:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2218178</guid>
    </item>
    <item>
      <title>Proper Design of Inlets and Drains for Roadways and Urban Developments</title>
      <link>https://trid.trb.org/View/2279612</link>
      <description><![CDATA[The design of drainage systems form an integral and important part of roadways and urban development projects. Drainage pipes are generally designed based on the rational formula, using the rainfall intensity for a short duration storm. The runoff coefficients and drainage areas are determined using site plans and topographic maps. Engineers often neglect to analyze the capacity of inlets in the design process. As a result, many storm drain systems flow at less than the design capacity because the stormwater runoff cannot get into the drains. Inadequate inlet capacity may cause flooding on roadways which creates a hazard to or interruption of traffic. Because of the same deficiency, the runoff cannot fully enter into the detention basins in urban developments. This not only results in an inefficient use of detention basins, but more importantly, the bypassing water may create downstream flooding. This paper presents proper procedures for the design of inlets. It includes simplified formulas and design charts to aid engineers to estimate the spread of water in gutters and to calculate the flow captured by inlets. The paper also develops an equation for the calculation of spread flow for roadways with zero longitudinal grade where the standard gutter flow equation fails to hold. This equation was employed to calculate the spread flow for inlets on a section of the NJ Turnpike which traverses through Meadowlands at zero or nearly zero grade. The paper also recommends methods of improving drainage conditions for roadway in flatlands.]]></description>
      <pubDate>Sun, 25 Aug 2024 16:57:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2279612</guid>
    </item>
    <item>
      <title>Urban Drainage Design Fourth Edition</title>
      <link>https://trid.trb.org/View/2377999</link>
      <description><![CDATA[This manual provides a comprehensive and practical guide for the design of storm drainage systems associated with transportation facilities. Information is provided for the design of storm drainage systems that collect, convey, and discharge stormwater flowing within and along the highway right-of-way. Methods and procedures are given for the hydraulic design of storm drainage systems. Design methods are presented for evaluating rainfall and runoff magnitude, pavement drainage, gutter flow, inlet design, median and roadside ditch flow, structure design, and storm drain piping. Procedures for the design of detention facilities are also presented, along with an overview of stormwater pumping stations and urban water quality practices.]]></description>
      <pubDate>Thu, 23 May 2024 13:28:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2377999</guid>
    </item>
    <item>
      <title>Culvert/Storm Drain Evaluation Technologies</title>
      <link>https://trid.trb.org/View/2373878</link>
      <description><![CDATA[While LiDAR (light detection and ranging) is not a new technology to UDOT, mobile LiDAR has not been used to enhance culvert inspections. The study reviewed two types of mobile scanning technologies for testing culverts, Pocket LiDAR (iPhone 12 Pro based laser emitter that is used to improve accuracy of photogrammetry) and SLAM LiDAR (simultaneous location and mapping). The control was made with hand measurements or with Terrestrial LiDAR (which is a portable unit that scans an area with multiple static scans, similar to what UDOT uses for some of its surveying). This testing was performed to see if new versions of LiDAR could be used to supplement and improve culvert inspections within the scope of UDOT’s rating criteria. UDOT had an overall goal to be able to automate inspections so that a culvert inspection expert did not have to watch the video after the inspection to evaluate each defect that was found in a pipe. Culvert inspections offer challenges that are atypical to Terrestrial LiDAR surveying. While Terrestrial LiDAR had a lot of utility for its ability to gather large amounts of point cloud data from a distance with outdoor lighting, LiDAR in culverts is done over very small distances and with artificial lighting. Finding appropriate testing culverts that were easy and safe to enter with varied pipe materials was a challenge as many of the larger culverts that could be walked through are not readily accessible. This is often due to traffic safety issues with locations along state highways, water within the pipe or with locations where entry is limited due to structures. By coordinating with two groups that specialized in mobile LiDAR and determining a reasonable sample size that could be accomplished in two days, a group of 11 pipes was set. These pipes were: concrete, plastic and metal pipe types; had different diameters; were near enough that travel time was not a drain on resources; large enough for walk-thru mobile scanning; and the pipes exhibited varied defects. The testing found that the mobile technologies did well with some aspects of pipe measurements, including diameter, deflection, grade and joint gaps. The current measurement refinement level of this technology does not allow for meeting the UDOT inspection criteria for smaller defects such as fractures, surface deterioration, localized buckling, corrosion, and infiltration/exfiltration.]]></description>
      <pubDate>Tue, 21 May 2024 10:54:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2373878</guid>
    </item>
    <item>
      <title>Large Interceptor Capacity Analysis Using a Dynamic Hydraulic Model</title>
      <link>https://trid.trb.org/View/2271587</link>
      <description><![CDATA[High Level Sewershed (HLSS) is one of eight sewersheds in the City of Baltimore with a population of about 100,000 people in its 4,600 acres of drainage area (Figure 1). The High Level Interceptor (HLI) was built in 1912, and collects flow from the HLSS and surrounding drainage areas. This interceptor has a triple barrel siphon (42", 42" and 36") that crosses under a major highway. At the downstream end of the siphon, the low spot on the HLI surface profile where HLSS and another sewershed meet, sanitary sewer overflows (SSOs) have been observed in the past. To understand the system performance and develop recommendations to alleviate the overflow, flow monitoring was conducted at both ends of the siphon as part of the City-wide sewershed study and SSO elimination planning efforts. Overflow volume during a wet event and Hazen-William coefficients of the siphon tubes were calculated using the measured flow and water depth data. In addition to this localized siphon analysis, a HLSS hydraulic model was developed and calibrated based on city-wide flow monitoring conducted at 40 locations for one year. Sonar inspection conducted along the HLI revealed a significant sediment accumulation in the downstream reaches. This sediment data was used to accurately calibrate the siphon behavior as well as the downstream portion of HLI. This paper describes the field observations and dynamic hydraulic modeling efforts pursued to characterize the capacity issues and make appropriate recommendations to the City of Baltimore.]]></description>
      <pubDate>Fri, 22 Dec 2023 08:47:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2271587</guid>
    </item>
    <item>
      <title>Preliminary Results of the Examination of Thermal Impacts from Stormwater BMPs</title>
      <link>https://trid.trb.org/View/2271560</link>
      <description><![CDATA[The preliminary results to examine the 4 years of monitoring of runoff temperature for a range of stormwater management BMPs and the affects on stormwater runoff temperatures in relation to established environmental indicators are presented for a study in Durham, NH. Research indicates that thermal impacts are not limited to summer months but include other times important for life-cycle considerations. Stormwater BMPs examined include conventional, Low Impact Development, and manufactured treatment designs. Surface systems that are exposed to direct sunlight have been shown to increase already elevated runoff temperatures, while other systems that provide treatment by infiltration and filtration can reduce runoff temperatures by thermal exchange with cool subsurface materials. Results indicate there is an increase in the thermal mass of runoff from a storm sewer system draining an area of asphalt pavement with a 97% impervious cover. For the storm sewer system, the mean EMT value of 53.5°F (± 12.7°F), which is greater than the mean groundwater temperature, which resembles the mean daily average annual air temperature, of 47°F that feed coldwater streams (NCDC 2005). The examination of stormwater BMPs indicates that the larger surface systems will see greater thermal variations and the larger subsurface systems will see greater thermal buffering. One large surface system, the Retention Pond, with a mean value of 61.8°F (± 11.8°F) is susceptible to greater thermal variations. One large subsurface system, the Gravel Wetland, whose mean value of 48.7°F (± 12.0°F), indicates a greater thermal buffering. The Runoff, the Retention Pond, and the Gravel Wetland calculated maximum and minimum values of event mean temperatures of 75.4°F and 33.3°F, 81.3°F and 32.7°F, 70.0°F and 33.0°F respectively. These temperatures are important to note when considering lethality indices of aquatic species. Another indicator of the health of a system that has been utilized by environmental monitoring programs is the mean July temperature of the stream under investigation]]></description>
      <pubDate>Fri, 22 Dec 2023 08:47:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2271560</guid>
    </item>
    <item>
      <title>Global Solutions for Urban Drainage</title>
      <link>https://trid.trb.org/View/2274424</link>
      <description><![CDATA[Proceedings of the Ninth International Conference on Urban Drainage, held in Portland, Oregon, September 8-13, 2002. Sponsored by Urban Water Resources Research Council of the Environmental Water Resources Institute of ASCE; International Association for Hydraulic Research; Joint Committee on Urban Drainage of the International Water Association. This collection of 329 papers presents state-of-the-art solutions to common urban storm drainage problems, such as flooding, combined sewer overflows, nonpoint-source runoff quality, urban streams, and more. Papers report on practical applications of new and traditional methods of analysis, design, construction, operation, and maintenance of urban storm drainage systems, as well as on institutional and educational approaches for improving the urban water environment. Topics include: best management practices; decision support and modeling; combined sewer overflows and sanitary sewer overflows; stormwater management; urban streams; monitoring; precipitation and hydrology; flooding; education and involvement; sewer processes; hydraulics; real-time control; and Portland, Oregon, wet weather.]]></description>
      <pubDate>Wed, 25 Oct 2023 10:14:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2274424</guid>
    </item>
    <item>
      <title>Causes and Effects of Culvert Blockage during Large Storms</title>
      <link>https://trid.trb.org/View/2201032</link>
      <description><![CDATA[This paper presents data collected on the blockage of culverts and bridge openings by debris during a major storm. The dominant factor in determining the degree of blockage is the size of the structure's clear opening. Culvert or bridge openings greater than about 6 m are unlikely to block, and if they do block, it is likely to be only a partial blockage. Culverts with openings less than about 6 m are prone to blockage. The data collected for this storm indicates that these culverts can experience the full range, from unblocked to completely blocked.]]></description>
      <pubDate>Wed, 25 Oct 2023 10:14:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2201032</guid>
    </item>
    <item>
      <title>Drainage 101 County Roadways, City Streets and Drainageways: Best Practices and Resources Guide</title>
      <link>https://trid.trb.org/View/2197911</link>
      <description><![CDATA[The time individual engineers, administrators and their staff invest in researching drainage law and defining the best approach to solving drainage issues can be considerable. This document provides quick access to information needed to solve those problems and discover legal solutions to recurring drainage issues and the time saved could be invested in other pressing public responsibilities. This study also contains information which might be useful to local elected officials, private property owners and other interested parties as it offers concise educational materials that simplify and inform them on drainage issues and laws related to regional watershed protection, county road/highway ditches, city street/storm sewers and related drainage infrastructure.]]></description>
      <pubDate>Fri, 23 Jun 2023 12:21:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2197911</guid>
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