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    <title>Research in Progress (RIP)</title>
    <link>https://rip.trb.org/</link>
    <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>How Can NMDOT Use TSD Data to Support Pavement Design</title>
      <link>https://rip.trb.org/View/2704033</link>
      <description><![CDATA[TSD is a valuable technology for measuring surface deflections at short intervals and capturing data on roughness, texture, and rutting at traffic speed. Several highway agencies in the United States and other countries are currently either looking into how to use TSD data in their pavement management system (PMS) to ensure responsible expenditure of taxpayers’ dollars.]]></description>
      <pubDate>Wed, 20 May 2026 11:15:23 GMT</pubDate>
      <guid>https://rip.trb.org/View/2704033</guid>
    </item>
    <item>
      <title>Finding the Bed Shear Stress Using the Logarithmic Law at Channel Roughness Transitions</title>
      <link>https://rip.trb.org/View/2672767</link>
      <description><![CDATA[Flow through transition of bed roughness occurs in many situations in highway transportation including culverts, bridge abutments, and roadways in the floodplain, where the bed materials can change abruptly from one type to another. A sudden change in bed roughness also occurs frequently in the laboratory when soil erosion and scour is studied using a sediment recess in an open-channel flume. In all the above, the bed shear stress is a fundamental flow parameter that must be determined accurately.

A research project is proposed to investigate the use of logarithmic law (log law) for finding bed shear stress near a sudden change in bed roughness. Velocity field measurements will be obtained using a Particle Image Velocimetry (PIV) system. The measured data will be used to determine the distribution of bed shear stress by control volume analysis using the linear momentum equation to determine whether the log law can be applied to a developing boundary layer downstream of a bed roughness transition and develop procedures to reduce the measurement uncertainty of the method.]]></description>
      <pubDate>Mon, 23 Feb 2026 13:58:52 GMT</pubDate>
      <guid>https://rip.trb.org/View/2672767</guid>
    </item>
    <item>
      <title>Evaluation of Ride Quality and Tining/Finishing Practices for Concrete Pavements</title>
      <link>https://rip.trb.org/View/2671982</link>
      <description><![CDATA[Many state departments of transportation (DOTs), including Wisconsin Department of Transportation (WisDOT), use the International Roughness Index (IRI) to assess ride quality. The researchers shall review WisDOT’s incentives and disincentives for IRI Ride and compare them to practices with neighboring states. This study will guide the incorporation of ride quality considerations into Wisconsin’s Facility Development Manual (FDM), ensuring that the design process accounts for the elements necessary to produce good ride quality. These elements include traffic staging, lane width consistency, the need for tining or turf drag, and the handling of horizontal/vertical curves. The FDM should also include guidance on integrating ProVAL software into the design stage to predict achievable ride quality before construction begins.]]></description>
      <pubDate>Wed, 18 Feb 2026 11:18:56 GMT</pubDate>
      <guid>https://rip.trb.org/View/2671982</guid>
    </item>
    <item>
      <title>Finite Element Method (FEM) Matrix Study for Rapid Travel Profiler Curl/Warp Correlations</title>
      <link>https://rip.trb.org/View/2562306</link>
      <description><![CDATA[It is known from experience over the years that development of unusual large warp curvatures in jointed concrete pavement slabs can cause accelerated or rapid deterioration rates for the pavement and result in poor ride quality. Michigan Department of Transportation (MDOT) has experienced occasional events of large upwarp or downwarp; a complex phenomenon not well understood or easily simulated with structural analysis tools. It has also been shown that large variation in daily slab curvatures caused by morning to afternoon thermal gradient variations (curling) can affect International Roughness Index (IRI) calculations used for initial smoothness specifications control and for pavement management systems. A current MDOT focus is to undertake studies of how warp and curl affect initial smoothness IRI calculations and long-term pavement management system IRI values. Rapid travel profiling devices can accurately measure average concrete pavement slab curvature and daily curvature changes caused by varying temperature gradients. These profiling devices measure variations in curvature present along the traveled wheel paths in the slabs. Procedures exist for quantifying curvature in slabs from rapid travel profile data. Thus, the problem to address under this proposed research is to develop a structural back-calculation or matching tool from modern finite element type analysis methods that will match observed slab curvature magnitudes and variations in the wheel path location, to those predicted using finite element method (FEM) models.]]></description>
      <pubDate>Fri, 06 Jun 2025 15:17:39 GMT</pubDate>
      <guid>https://rip.trb.org/View/2562306</guid>
    </item>
    <item>
      <title>LTPP Data Analysis: Feasibility of Using LTPP Data to Improve Use of FWD and Longitudinal Profile Measurements</title>
      <link>https://rip.trb.org/View/2458789</link>
      <description><![CDATA[Pavement deflections obtained from falling weight deflectometer (FWD) measurements and roughness obtained from longitudinal profile measurements are used together with other measurements to assess pavement condition.  These measurements are influenced by the temporal and diurnal changes; the consideration of this influence is necessary for accurate assessment of pavement condition. The Long-Term Pavement Performance Program (LTPP) Seasonal Monitoring Program (SMP) was initiated to obtain data on the influence of temporal changes on pavement deflection and roughness. However, the temporal and diurnal data contained in the LTPP database have not been applied to improve the practices of measuring deflection and roughness, and their use has not been demonstrated. In addition, there is a concern about the adequacy of available LTPP data to accomplish this task. There was a need to assess the feasibility of using the LTPP SMP and diurnal measurements for developing guidelines for improved use of FWD and longitudinal profile measurements. The findings of this assessment will help make a decision regarding the need for further research. OBJECTIVE: The objective of this research was to evaluate the feasibility of using data from the LTPP SMP and diurnal measurements for developing guidelines for improved use of FWD and longitudinal profile measurements data in evaluating pavement condition. The research shall address both asphalt and concrete pavements.

 ]]></description>
      <pubDate>Mon, 18 Nov 2024 19:44:21 GMT</pubDate>
      <guid>https://rip.trb.org/View/2458789</guid>
    </item>
    <item>
      <title>Impact of Asphalt Lift Thickness on Pavement Density and Durability</title>
      <link>https://rip.trb.org/View/2404007</link>
      <description><![CDATA[A key factor in achieving adequate density is the ratio of the asphalt lift thickness to the size of the aggregate in the mixture. Generally, it is considered that lifts need to be thick enough to provide room for the aggregates to reorient and densify, but not so thick that the bottom of the lift does not feel the compaction force and therefore does not densify. In recent publications, researchers recommended the t/NMAS ratio be at least 3:1 for fine graded mixes and at least 4:1 for coarse graded mixes; however, there is no consensus on what value is best. In a limited number of projects, pavements were built with higher lift thicknesses. Since most of the work was of empirical nature, the results were mixed in terms of achieving desired density levels and meeting roughness (IRI) requirements.
The research group at UofM has developed a rational approach to asphalt compaction, that has led to better guidelines for designing Superpave 5 mixtures and for modelling the compaction process in asphalt mixtures. The work included analyzing the compaction curves of gyratory cylinders of various heights, and the model predictions were very good.

The research team proposes to use this new approach, validated in previous research on Superpave 5 mixtures, to design asphalt mixtures that can achieve desired densities, and also desired surface roughness, at higher lift thickness values. Anecdotal evidence indicates that using higher lift thickness, which has better heat retention, has resulted in better densities, compared to traditional lift thickness values; however, the increase in surface roughness has deterred contractors from using this cost-saving method. It becomes then very important to better understand the factors responsible for the increase in surface roughness, and most importantly, to determine if more durable and more cost-effective asphalt pavements can be built using higher lift thicknesses, in spite of higher initial roughness values.]]></description>
      <pubDate>Tue, 16 Jul 2024 15:23:56 GMT</pubDate>
      <guid>https://rip.trb.org/View/2404007</guid>
    </item>
    <item>
      <title>Integration and Deployment of Novel Tools for Rapid Assessment of Pavement Conditions and Remaining Life</title>
      <link>https://rip.trb.org/View/2291280</link>
      <description><![CDATA[Pavement condition evaluation is an essential component of a Pavement Management System (PMS) facilitating planning for necessary maintenance and rehabilitation activities and preserving the road network in acceptable conditions. The timely detection and accurate quantification of pavement distresses assist PMS engineers in forecasting future pavement deterioration and planning for needed repair strategies. Road surveying vehicles that are equipped with computers, sensors, cameras, and lasers, are commonly used to automatically collect high-definition pavement images and have found wide acceptance by highway agencies. However, the cost of such a survey is high and cannot be afforded by many agencies, such as those responsible for city streets and rural roads.
	The ultimate goal of this study is to provide small to medium-sized road agencies (e.g., city and county roads) that are responsible for a local road network with a simple tool with the ability to predict pavement condition indices, roughness, and remaining service life based on a limited set of inputs such as pavement age and classification. These inputs are commonly available to road agencies. This AI and data analytics-based tool may be used in the case of the unavailability of inertial profilers and other sophisticated and expensive tools. 
	To achieve the aforementioned goal, the proposed research activities are organized into five tasks. (1) Pavement performance data including pavement condition index, roughness, cracking, and rutting will be collected from PMS databases. These data are based on pavement condition measurements that are collected biennially using a road surveying vehicle that provides a continuous assessment of the road network. (2) Artificial Neural Networks (ANN) models will then be developed to predict pavement performance parameters (e.g., roughness and pavement condition index) using simple input variables including pavement age, weather parameters, and road categories. (3) A computer-based interactive tool will be developed that can be used to predict pavement performance based on simple input variables. (4) The developed interactive tool will be tested and validated based on independent performance data that were not used in the development phase. The developed tool will be available as an interactive spreadsheet or other form of computer application or phone application. (5) A final report documenting the entire research effort will be prepared and submitted.

]]></description>
      <pubDate>Wed, 15 Nov 2023 17:03:48 GMT</pubDate>
      <guid>https://rip.trb.org/View/2291280</guid>
    </item>
    <item>
      <title>2295 ODOT Automated Bridge Survey</title>
      <link>https://rip.trb.org/View/2286453</link>
      <description><![CDATA[The purpose and scope of this research study will be to:  (1) develop an efficient, non-destructive, and cost-effective procedure to comprehensively evaluate the condition of approach slabs and bridge decks; (2) provide approach slab and bridge deck evaluations encompassing cracking and IRI data, ensuring a thorough understanding of their performance; (3) conduct deck surveys to document essential parameters such as crack size and location, spall locations, percentage of patches, and condition of expansion joints.  Identify areas requiring maintenance action based on a comprehensive assessment of ride quality, using 2D/3D images, roughness data, and right-of-way images to categorize conditions as Good, Fair, or Poor; and (4) develop a non-destructive and cost-effective approach to determine the actual dynamic impact factor (IM) on both the approach slab and bridge decks based on their condition.   ]]></description>
      <pubDate>Fri, 03 Nov 2023 11:56:27 GMT</pubDate>
      <guid>https://rip.trb.org/View/2286453</guid>
    </item>
    <item>
      <title>Identifying Pavement Improvement Projects for Enhanced Safety</title>
      <link>https://rip.trb.org/View/2255822</link>
      <description><![CDATA[The research teams will develop a method and tool for analyzing safety-related pavement data to identify candidate pavement safety projects, such as cross-slope improvement projects and flushing treatment projects. The research teams will assemble a dataset containing comprehensive data on the pavement, site condition, and crashes for a representative sample of on-system roadways. The research teams will conduct a comprehensive analysis of the integrated dataset to identify critical combinations and thresholds of pavement conditions that may pose a safety hazard and use these factors to assess pavement susceptibility to crashes. The research teams will quantify the pavement crash susceptibility based on measurable pavement characteristics such as cross-slope, geometrics, distresses (e.g., rutting, flushing), skid resistance, and roughness. Finally, the research teams will develop a data analysis and visualization tool for assessing pavement crash susceptibility and recommending solutions to reduce crash risks. Texas Department of Transportation's (TxDOT’s) districts will be able to use this tool to identify potential site-specific crash contributing factors and proactively select appropriate pavement safety improvement projects.]]></description>
      <pubDate>Wed, 27 Sep 2023 14:16:16 GMT</pubDate>
      <guid>https://rip.trb.org/View/2255822</guid>
    </item>
    <item>
      <title>Performance Index Rating and Maintenance Cost Assignment for Ramps, Acceleration and Deceleration Lanes in Louisiana</title>
      <link>https://rip.trb.org/View/1938471</link>
      <description><![CDATA[The objectives of this study are as follows:
(1) Ascertain whether there are differences in International Roughness Index (IRI) and Performance Index (PI) values of analysis lanes as compared to ramps, acceleration lanes and deceleration lanes at project and network level.
(2) Propose a framework for measuring and characterizing IRI and PI values for ramps, acceleration lanes and deceleration lanes; and
(3) Establish and propose guidelines to address additional treatment costs specific to ramps, acceleration lanes and deceleration lanes at the project and network levels.
]]></description>
      <pubDate>Tue, 05 Apr 2022 15:36:07 GMT</pubDate>
      <guid>https://rip.trb.org/View/1938471</guid>
    </item>
    <item>
      <title>SPR-4604:  Demonstration of Infrared Heating System for Mitigation of Positive Elevation Change Areas of Localized Roughness (Bumps) in HMA</title>
      <link>https://rip.trb.org/View/1898916</link>
      <description><![CDATA[The primary purpose of this research is to demonstrate the process of utilizing infrared technology to mitigate bumps in hot mix asphalt (HMA)/composite pavements. An infrared pavement heating system consisting of a self contained maintenance trailer, capable of transporting heating equipment, infrared heating array, compaction equipment and hand tools will be purchased. It is anticipated that procurement of the complete system will increase the efficiency over needing multiple vehicles and systems to convey makeup HMA material and compaction equipment separately.]]></description>
      <pubDate>Tue, 21 Dec 2021 10:25:47 GMT</pubDate>
      <guid>https://rip.trb.org/View/1898916</guid>
    </item>
    <item>
      <title>Improvement of Approach Smoothness on Integral Abutment Bridges</title>
      <link>https://rip.trb.org/View/1843615</link>
      <description><![CDATA[Approach slabs span the embankment directly behind the bridge abutment backwall to provide a smooth transition between the bridge and pavement. Ride roughness at the approach slab has been a persistent problem, requiring significant maintenance for many highway agencies. The problem is so prevalent it is commonly referred to as “the bump at the end of a bridge”. 

Extensive research has identified time-dependent consolidation of the embankment and foundation soil along with inadequate compaction as primary causes for approach roughness. The natural movement of an integral bridge abutment, which the South Dakota Department of Transportation (SDDOT) uses extensively, can further compress the embankment material. Additional causes include design details, drainage, soil erosion, embankment material quality, and construction. The complexity of the problem is evidence that bridge approach roughness may be due to various conditions happening simultaneously, with a solution achievable by design engineers, geotechnical engineers, field engineers, and contractors working together.

Over the past 30 years SDDOT has used various methods—including various embankment geometries, various backfill materials, addition and removal of geotextile fabric, different drainage configurations, and different joint details at sleeper slabs—to build and maintain smooth bridge approaches. However, the bump is still a major complaint for road users, still expensive to repair, and still a potential safety hazard.

The objectives of this project are to: (1) Analyze and compare the performance of SDDOT’s current and past design, construction, and maintenance practices to resolve integral abutment bridge approach slab roughness; (2) Investigate the design, construction, and maintenance practices of other United States and European highway agencies to reduce approach slab roughness on integral abutment bridges; (3) 	Recommend feasible new designs and changes to SDDOT’s current design, construction, and maintenance practices to reduce approach slab roughness on integral abutment bridges; and (4) Recommend a strategy for future monitoring and evaluation of roughness at integral abutment bridge approaches. 
]]></description>
      <pubDate>Fri, 26 Mar 2021 16:14:55 GMT</pubDate>
      <guid>https://rip.trb.org/View/1843615</guid>
    </item>
    <item>
      <title>LTPP Data Analysis: Guidelines to Improve Use of FWD and Longitudinal Profile Measurements</title>
      <link>https://rip.trb.org/View/1841151</link>
      <description><![CDATA[Pavement deflections obtained from falling weight deflectometer (FWD) measurements and roughness obtained from longitudinal profile measurements are used together with other measurements to assess pavement condition and performance. These measurements are influenced by the temporal and/or diurnal variations; their consideration is necessary for accurate assessment of pavement condition.

The Long-Term Pavement Performance Program (LTPP) Seasonal Monitoring Program (SMP) was initiated to obtain data on the influence of temporal variations on pavement deflection and roughness. However, the temporal and diurnal data contained in the LTPP database (see Special Note A) have not been applied to improve the practices of measuring deflection and roughness, and their use has not been demonstrated. Also, recent work completed under NCHRP Project 20-50(22), “LTPP Data Analysis: Feasibility of Using LTPP data to improve Use of FWD and Longitudinal Profile Measurements” identified some of the issues related to the use of FWD and longitudinal profile measurements and proposed a preliminary research plan for addressing these issues (see Special Note B). However, additional research was needed to further define and address the issues associated with the effects of temporal and diurnal variations on FWD and longitudinal profile measurements, and to develop guidelines to improve these measurements and their use in evaluating pavement condition.
 
The objective of this research was to develop guidelines for improved use of FWD and longitudinal profile measurements data in evaluating pavement condition by considering the effects of temporal and/or diurnal variations. The research was to address both asphalt and concrete pavements and focus on using the data available in LTPP database (including those for SMP test sections).
 ]]></description>
      <pubDate>Mon, 15 Mar 2021 21:16:22 GMT</pubDate>
      <guid>https://rip.trb.org/View/1841151</guid>
    </item>
    <item>
      <title>Development of a Smartphone-Based Road Performance Data Collection Tool</title>
      <link>https://rip.trb.org/View/1722359</link>
      <description><![CDATA[The objectives of this research is listed as follows:
(1) The first objective of this research would be to develop a smartphone-based (mobile application) pavement roughness measurement system for collecting roughness data at an appropriate frequency required for pavement management and maintenance planning.
(2) The second objective is to identify and evaluate the potential capacities of a smartphone-based tool for detecting and measuring other road surface distress types including cracking, rutting, faulting, and so on.
(3) The third objective is to develop a standardized nonproprietary data collection tool that can be used to collect roughness data required for pavement management and would also have the capabilities of providing the location and optional sensor data necessary for automatic vehicle location (AVL) systems.
(4) The fourth objective would be to test and calibrate the standardized nonproprietary collection tool for the various selected brands and types of popular Android smartphones in comparison to Class 1 profilometer specified by ASTM E 950 (e.g., high speed inertial profilometer unit, if available) with known high accuracy of international roughness index (IRI)wirel and global positioning system (GPS) values to allow for field implementation being used in different types of vehicles.
(5) The fifth objective is to evaluate effective options to provide wireless communication links to deliver data between the smartphone or nonproprietary collection tool and the ICEA Service Bureau.]]></description>
      <pubDate>Wed, 15 Jul 2020 17:08:14 GMT</pubDate>
      <guid>https://rip.trb.org/View/1722359</guid>
    </item>
    <item>
      <title>Synthesis of Information Related to Highway Practices. Topic 52-03. Practices for Ensuring Bridge Surface Smoothness</title>
      <link>https://rip.trb.org/View/1707233</link>
      <description><![CDATA[Rough bridge surfaces can increase user costs by accumulative wear and tear on vehicles, increase freight costs resulting from damage to goods or packaging, add to potential safety concerns with nonuniform tire loads, decrease the life of a structure by increasing dynamic loads, and reduce user satisfaction. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 580: Practices for Ensuring the Smoothness of Concrete Bridge Decks documents state departments of transportation (DOTs) practices used to evaluate the smoothness of concrete bridge decks when constructed, procedures used to keep track of the roughness of concrete bridge decks over time, and practices used to maintain the smoothness of concrete bridge decks through the life cycle of the structure.]]></description>
      <pubDate>Tue, 19 May 2020 11:46:05 GMT</pubDate>
      <guid>https://rip.trb.org/View/1707233</guid>
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