Different choices in the budget assigned to road preservation and repair should be considered to find the optimal contribution of the road network to greenhouse gas (GHG) emissions mitigation and to meet targets set in the Paris Agreement on climate change. "Potential Contribution of Deflection-Induced Fuel Consumption to U.S. Greenhouse Gas Emissions,"  by Hassam Azarijafari, Jeremy Grego...

The TRB Centennial Book is available for purchase in ebook or print format. In The Transportation Research Board, 1920–2020: Everyone Interested Is Invited , author Sarah Jo Peterson tells the story of how people and institutions created and have continued to shape TRB. In a compelling narrative accompanied by more than 150 images exploring the history of transportation and research, she argues...

Performance testing of asphalt mixtures is becoming more widespread for a variety of reasons and with a variety of testing devices. The tests results are sensitive to the procedures used in preparation of the specimens. Guidelines exist for conducting the tests; however, they do not all provide uniform or comprehensive direction for fabricating test specimens. The TRB National Cooperative Highw...

Issue Number 326 of TR News magazine is available in full to subscribers. Here is a sample from the issue: a 14-page photo collage of the 99th Transportation Research Board Annual Meeting from January 12–16, 2020 in Washington, D.C. Do you see yourself in any of the photos?

The March-April 2020 issue of TR News (#326) - including a cover feature on TRB's "century of progress and foundation for the future" of transportation research - is available in hard copy and digital copy for subscribers. For those who are not subscribers, the table of contents is available. Other feature articles in the issue include ones on whether research processes can keep up, accessible ...

Topics in the November–December 2019 issue of TR News include an analysis of the #TRBAM Annual Meeting Twitter hashtag to understand communication dynamics; climate change, a critical transportation issue; assessing, marking, and coding highway structures in emergencies; and more. This issue also kicks off the magazine’s yearlong celebration of the 100th anniversary of TRB, which will include t...

Satisfactory pavement performance can only be assured with an appropriate process control to ensure compacted materials meet proper density and stiffness requirements. The pre-publication draft of the TRB National Cooperative Highway Research Program's NCHRP Research Report 933: Evaluating Mechanical Properties of Earth Material During Intelligent Compaction details the development of procedure...

One of the most time-honored of the technical activities that TRB performs, state visits revealed lots of interesting issues in 2019, including a lot around the important role state Departments of Transportation increasingly have around data needs. The TRB staff summary of the visits, each of which last one or two days and typically consist of meetings with various levels of DOT management; dis...

The transportation industry faces a wide range of plausible future drivers and scenarios that could affect standard practices over the next 30 to 50 years. Because the range of plausible futures over such a long-term period is very broad, making a focused prediction of the implications for highway infrastructure preservation, maintenance, and renewal (PMR) is quite challenging. The TRB National...

Issue 323 of TRB's magazine complements our recent short video Your Future in Transportation . The September-October 2019 issue  has several features on the workforce topic, including ones called " People, Organizations, Jobs, and Businesses for Tomorrow’s Transportation, "The Future Multimodal Workforce," "How to Win the War for Talent," and "Building a Business Case for Increasing Divers...

In determining what is effective in preventing or slowing ice formation and growth on roadways and bridges, it was found that biomimetic antifreeze molecules (BAMs) would not effectively melt ice once it has formed nor provide additional synergistic benefit to using the molecules in tandem with traditional deicers. Contrastingly, BAMs did prevent freeze-thaw damage in cement paste and concrete....

The January-February 2020 issue of TR News - including a cover feature on the "radical" transportation logistics of the Burning Man festival - is available in hard copy and digital copy for subscribers. For those who are not subscribers, the table of contents is available. Other feature articles in the issue include ones on data's critical role in transportation decisions, the transportation ne...

A new prestressing system, named Adaptive Prestressing System, has been proven in this study to be an innovative technique that holds great promise as a transformative, more efficient, and safer prestressing method for concrete crossties in railway systems. The TRB IDEA (Innovations Deserving Exploratory Analysis) Program's Rail Safety IDEA Final Report 33: Adaptive Prestressing System for Conc...

The past few years have seen some significant advances in concrete technology. For example, newer concrete incorporating advances in admixtures and cementitious materials has emerged. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 544: Concrete Technology for Transportation Applications documents how state departments of transportation select and deploy concrete technol...

The Wisconsin DOT issues both single- and multi-trip permits for Oversize–Overweight (OSOW) vehicles. As the number of OSOW vehicle permits issued in Wisconsin have increased in recent years, the management and analysis of OSOW permit data has become more labor-intensive and time-consuming. This "Research Pays Off" feature in  TR News edition 324 (November-December 2019), by Hani Titi, Nic...

The majority of instances of explicit consideration of service life design has been limited to signature bridges and other projects where extended service lives (in other words, greater than 100 years) are specified by the owner. Many state departments of transportation and other transportation agencies have recognized the importance of implementing service life design for typical highway bridg...

This article is adapted from The Transportation Research Board, 1920–2020: Everyone Interested Is Invited , to be published by the National Academies Press in January 2020. TRB can be best understood as an infrastructure—one that people purposely designed, carefully constructed, and devotedly maintained to share and strengthen knowledge about transportation. The core missions and structures tha...

There are several best management practices that are good at removing particulate-bound pollutants by settling, filtering, and, in the case of wetlands, settling, uptake, and incorporation of pollutants into biological matter (e.g., natural organic matter). However, a longstanding goal of stormwater treatment is the removal of the stormwater pollutant fraction that cannot be readily settled or ...

The November-December 2019 issue of TR News —with a focus on climate change resilience—is available in hard copy and digital copy for subscribers. For those who are not subscribers, the table of contents is available. Other feature articles in the issue include ones on the history of both TRB and transportation in general and a preview of the TRB Annual Meeting slated for January in Washington ...

Concrete is a porous material that allows materials to move through it. The number of pores connected in the concrete, also known as the permeability, influences the ability of fluids to penetration the concrete. And this permeability parameter is an important transport mechanism for freeze-thaw damage, corrosion, alkali silica reaction, and sulfate attack. The TRB Innovations Deserving Explora...

Load testing of bridges to assess bridge performance has been in practice since at least 1891 in Switzerland. In times when engineering models were not as accurate and available as today, a critical step in the construction of a bridge was to load test prior to opening or during the opening ceremony of the bridge. Several bridges, including ones in Serbia, Switzerland, and France, collapsed dur...

Expansive soils, also known as swell-shrink soils, have been a problem for civil infrastructure such as roads and foundations since ancient times. These soils swell and shrink with changes in moisture content, causing buildings and pavements to crack. The reason for this behavior is the presence of the heaving/swelling mineral that expands when exposed to water. These soils are present in the m...

Concrete is the most widely used synthetic material on earth. In the U.S., more than 75 percent of bridges and more than 60 percent of interstate highways are made of concrete. There is no other bulk material on the horizon that could replace concrete as the backbone for our increasing demands in infrastructures. Despite several decades of studies, concrete bridges, highways and infrastructures...

Information exchanged during the 97th Annual Meeting of the Transportation Research Board in a session titled "Relationship Between Laboratory Cracking Tests and Field Performance of Asphalt Mixtures" is captured in Transportation Research Circular E-C251: Relationship Between Laboratory Cracking Tests and Field Performance of Asphalt Mixtures . The document explores a significant amount of wor...

Traditionally, pavement management decision-making has relied on surface cracking as an indicator of structural condition. However, with early-intervention preservation activities to extend the life of pavements, surface cracks no longer are a reliable indicator of structural condition. In the past 15 years, traffic speed deflection devices (TSDDs) have been developed to measure pavement struct...

More than 90 percent of highways and roads in the United States are built using hot-mix asphalt (HMA) or warm-mix asphalt mixtures, and these mixtures now recycle more than 99 percent of some 76.2 million tons of reclaimed asphalt pavement (RAP) and about 1 million tons of recycled asphalt shingles (RAS). According to the National Asphalt Pavement Association, cost savings in 2017 totaled appro...

Global business and tourism depend heavily on the efficient operation of airports and movement of passengers, baggage, and cargo across many areas. With increasing demand and connectivity requirements for airports comes the need for more sophisticated simulation and modeling tools to validate design assumptions. Furthermore, airport design and planning decisions have significant impacts on poli...

The performance of flexible and rigid pavements is known to be closely related to properties of the base, subbase, and/or subgrade. However, some recent research studies indicate that the performance predicted by this methodology shows a low sensitivity to the properties of underlying layers and does not always reflect the extent of the anticipated effect, so the procedures contained in the Ame...

“Pavement condition data” are essential inputs to the process of managing airport pavements and ensuring safe operations. The technology available today to collect pavement condition data is considerably different from that available even 20 years ago, and new technologies are being developed and introduced into practice at a rapid pace. ACRP Research Report 203: Guidelines for Collecting, Appl...

Pavement smoothness (or roughness) is used by state highway agencies for monitoring network condition and other purposes such as assessing construction quality and optimizing investments in preservation, rehabilitation, and reconstruction. States are also required to report the International Roughness Index (IRI) as an element of the federal Highway Performance Monitoring System (HPMS). Because...