Below are brief descriptions of products recently published online by the Federal Highway Administration's (FHWA) Office of Research, Development, and Technology. Some of the publications also may be available from the National Technical Information Service (NTIS). In some cases, limited copies are available from the Research and Technology (R&T) Product Distribution Center.

When ordering from NTIS, include the NTIS publication number (PB number) and the publication title. You also may visit the NTIS Web site at www.ntis.gov to order publications online. Call NTIS for current prices. For customers outside the United States, Canada, and Mexico, the cost is usually double the listed price. Address requests to:

Address requests for items available from:

For more information on R&T publications from FHWA, visit FHWA's Web site at www.fhwa.dot.gov, the Turner-Fairbank Highway Research Center's Web site at www.fhwa.dot.gov/research/tfhrc/, the National Transportation Library's Web site at http://ntl.bts.gov, or the OneDOT information network at http://dotlibrary.dot.gov.

Signs are essential to communicating regulatory, warning, and guidance information on roadways. A unique form of reflection known as retroreflectivity gives signs the ability to fulfill this role at night. Sign retroreflectivity, however, degrades over time. In response to a congressional directive aimed at ensuring safety, FHWA established minimum retroreflectivity levels for traffic signs and incorporated that information into the Manual on Uniform Traffic Control Devices (MUTCD).

One of the concerns expressed by transportation agency personnel responsible for conformance with these required minimum levels is the potential increase in tort exposure. Therefore, FHWA developed retroreflectivity maintenance methods that, when implemented as intended, provide agencies with a flexible means of achieving conformance and offer protection from potential tort claims.

This report describes a variety of methods agencies can use to meet and maintain minimum retroreflectivity requirements for signs. Specifically, the report outlines procedures to systematically identify signs that do not meet the minimum levels, initiate activities to upgrade signs as necessary, monitor the retroreflectivity of in-place signs, and update practices and policies for managing the nighttime visibility of signs. Agencies can use this information to help determine which retroreflectivity maintenance method or combination of methods best suits their needs.

The document is available from NTIS under order number PB2008106478.

FHWA's Focus newsletter has a mission to accelerate infrastructure innovations. Toward that end, the March 2008 issue features articles on the following topics: "Implementing an Accelerated Bridge Construction Program in Utah," "A Composite Solution to Repairing Overhead Sign Structures," "All About Steel Bridges," and "New Training on Cost Estimating for Today's Highway Projects." The newsletter also contains the popular highway technology calendar, which lists upcoming events that provide opportunities to learn more about infrastructure-related products and technologies.

The March issue of the newsletter is available at www.fhwa.dot.gov/publications/focus/08mar/index.cfm.

The April 2008 issue of Focus features articles on the following topics: "Green Highways: Partnering to Build More Environmentally Sustainable Roadways," "The Era of Intelligent Compaction Has Arrived," and "Warm-Mix Asphalt Debuts in Yellowstone National Park." This issue spotlights a peer-to-peer approach to improving work zone safety and mobility and FHWA's Pavement and Materials Environmental Stewardship Team. The newsletter also features a calendar of infrastructure-related events.

The April issue is available at www.fhwa.dot.gov/publications/focus/08apr/index.cfm.

The Nation's approximately 600,000 bridges, including those on the National Highway System and those maintained and operated by State and local entities, are essential to mobility. The Structures Laboratory at FHWA's Turner-Fairbank Highway Research Center specializes in developing and testing innovative bridge designs, materials, and construction processes that promise more efficient structures for the Nation's highway system.

The lab supports national bridge design specifications to improve the safety, reliability, and cost effectiveness of bridge construction in the United States. It also provides forensic investigation services to determine the causes of bridge structural failures and develops practices and procedures to help avoid these failures in the future. This fact sheet summarizes the lab's capabilities and equipment, as well as its mission, partners, and accomplishments.

The document is available at www.fhwa.dot.gov/publications/research/infrastructure/structures/07060/index.cfm.

Defining an Advanced Quality System and the Elements That Integrate It

Publication No. FHWA-HRT-07-058

This report summarizes the findings of the Advanced Quality Systems Workshop held in Washington, DC, in November 2006. Sponsored by FHWA, the workshop brought together researchers and practitioners to discuss exactly what constitutes an advanced quality system and how best to advance quality systems at State highway agencies. During the workshop, attendees defined advanced quality systems and noted that advanced quality systems should include quality assurance for both design and construction. The two are part of the same system, and State highway agencies need to be consistent in communicating to the contractor the desired quality and performance of construction. The report concludes that continuous improvement in construction quality occurs best when construction personnel at the State highway agency have a thorough understanding of the design, especially the assumptions regarding quality, and when they provide feedback to the designers on construction quality.

The document is available from NTIS under order number PB2007112617.

Ultra-high performance concrete (UHPC) is a relatively new material that has demonstrated good durability properties, high compressive strength, and usable tensile resistance. Recent studies on material characterization and structural behavior have shown the average compressive strength to be 193,100 kilopascal, kPa (28 kips per square inch, ksi) while a tensile strength of greater than 10,340 kPa (1.5 ksi) can be maintained throughout a tensile strain of approximately 0.010. Researchers conclude that these desirable mechanical properties make UHPC a worthy material for use on the Nation's highly stressed bridge decks.

Because UHPC exhibits a unique flexural behavior, a design methodology must be developed to distinguish it from that of traditional reinforced concrete. This report details UHPC flexural behavior, offers a design methodology, and presents the analysis of a two-way ribbed precast bridge deck. Without having design specifications for UHPC, the researchers used the 2006 American Association of State Highway and Transportation Officials' (AASHTO) load and resistance factor design (LRFD) specifications where appropriate in designing and analyzing the bridge deck. From the proposed design methodology, mechanics of the materials, and strain compatibility, the researchers analyzed the UHPC deck cross section for positive and negative moment capacities. The analysis revealed that the proposed UHPC deck design is capable of resisting the developed design loads. The researchers recommend further verification through physical testing of a full-scale UHPC two-way ribbed deck slab.

The document is available from NTIS under order number PB2007112112.

Researchers reviewed the AASHTO LRFD Bridge Design Specifications and the AASHTO LRFD Bridge Construction Specifications to identify provisions that affect the use of lightweight concrete. They also compiled a synthesis of research relevant to those provisions and proposed research problem statements to generate data to update the specifications in areas where gaps exist for lightweight concrete.

This report corresponds to a TechBrief titled Current Provisions and Needed Research for Lightweight Concrete in Highway Bridges (FHWA-HRT-07-051). Printed copies of the TechBrief are available from FHWA's Product Distribution Center. The report is available from NTIS under order number PB2007110768.

Freight transportation requires distinctly different planning from passenger transport. Existing data provide varying levels of detail, rarely offering a complete picture of a region's freight transportation. In many cases, local data collection efforts can provide more accurate and relevant data to support freight demand analysis and planning.

Understanding the strengths and weaknesses of available data sources can help transportation planners decide what data to use in particular situations. The Quick Response Freight Manual II explains current data sources and techniques for integrating freight data into planning efforts. Because States, metropolitan planning organizations, and other planning organizations possess varying degrees of knowledge and expertise in freight transportation, the manual offers methodologies for collecting and using data in models at the State and local levels.

The manual is an update to an earlier document developed in 1996. Like its predecessor, the new edition provides background on the U.S. freight transportation system and factors affecting demand. The manual can help planners locate available data and develop forecasts for facilities at a variety of geographic levels. Further, it provides simple techniques and transferable parameters for developing trip tables for freight vehicles.

The document is available at www.ops.fhwa.dot.gov/freight/publications/qrfm2/index.htm.