U.S. Department of Transportation
Federal Highway Administration
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Washington, DC 20590
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
This magazine is an archived publication and may contain dated technical, contact, and link information.
|Publication Number: FHWA-HRT-12-001 Date: November/December 2011|
Publication Number: FHWA-HRT-12-001
Issue No: Vol. 75 No. 3
Date: November/December 2011
Below are brief descriptions of communications products recently developed by the Federal Highway Administration’s (FHWA) Office of Research, Development, and Technology. All of the reports are or will soon be available from the National Technical Information Service (NTIS). In some cases, limited copies of the communications products are available from FHWA’s Research and Technology (R&T) Product Distribution Center (PDC).
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:
Requests for items available from the R&T Product Distribution Center should be addressed to:
R&T Product Distribution Center
Szanca Solutions/FHWA PDC
13710 Dunnings Highway
Claysburg, PA 16625
For more information on R&T communications products available from FHWA, visit FHWA's Web site at www.fhwa.dot.gov/research/library (or email email@example.com), or the National Transportation Library at ntl.bts.gov (or email firstname.lastname@example.org).
Publication No. FHWA-HRT-11-047
Current bridge coating practices typically involve multilayer coating consisting of a zinc-rich primer over an abrasive blast-cleaned surface and two additional coating layers on top of the primer. This three-coating approach offers improved protection against corrosion of steel bridges, but the overall cost is relatively higher than for its lead-based predecessors. This TechBrief presents details of an FHWA study that looks at the performance characteristics of several commercially available high-performance coating materials that can be applied to steel bridges as one-coat systems.
Researchers evaluated eight one-coat systems and two controls that performed well in the field and in prior FHWA studies. They also analyzed a three-coat system and a two-coat system using accelerated laboratory testing and outdoor exposure conditions. The researchers evaluated performance based on variations in color and gloss, changes in adhesion strength, changes in pencil scratch hardness, the development of surface defects, and rust creepage.
Several of the one-coat systems showed promising performance in accelerated laboratory testing and outdoor exposure conditions. Glass flake-reinforced polyester and high-build waterborne acrylic were among the top performing systems. The two-coat system developed many coating defects in accelerated laboratory testing and showed significant gloss reduction and rust creepage in outdoor exposure conditions, resulting in a low overall ranking. The three-coat system was the best performing system.
The document is available at www.fhwa.dot.gov/publications/research/infrastructure/bridge/11047/index.cfm. Printed copies are available from the PDC.
Publication No. FHWA-HRT-11-044
Poor traffic signal timing accounts for an estimated 10 percent of all traffic delay on major roadways alone, according to a study by the Oak Ridge National Laboratory. The goal of Advanced Traffic Signal Control Algorithms, a project under FHWA's Exploratory Advanced Research (EAR) Program, is to fundamentally rethink traffic signal operations based on the impending widespread availability of traffic probe data. This fact sheet includes information regarding changing signals, control concepts, efficient solutions, and research expectations.
The study looks at three control concepts: mobility, environment, and safety. The first, mobility, discusses strategies to avoid traffic saturation in the middle of a grid network. The aim is to use measurement samples to predict traffic, average travel times, and the proportion of stopped vehicles. The environmental concept examines fuel consumption and emissions results, and how signal phase and timing can be used to save fuel and lower emissions. The final concept, safety, looks at how to take full advantage of connected-vehicle data to analyze intersection geometry and detect approaching and waiting vehicles that may come into conflict. In addition, intersection priority could be given to emergency vehicles, transit vehicles, or individual vehicles under low-traffic conditions, reducing delays and the need to stop.
Research for the Advanced Traffic Signal Control Algorithms project is focused on the concept of vehicle-to-infrastructure cooperation via the Intelligent Transportation Systems program, an effort that could provide real-time information on the movements of vehicles throughout the road network, lead to changes in how traffic is controlled, and address the problem of congestion along arterial routes.
The document is available at www.fhwa.dot.gov/advancedresearch/pubs/11044/index.cfm. Printed copies are available from the PDC.
Publication No. FHWA-HRT-11-033
Driving at night is substantially more dangerous than driving during the day—the fatality rate, based on vehicle miles traveled, is three to four times higher. Development of Methodologies to Evaluate Nighttime Safety Implications of Roadway Visual Scene Under Cognitive Task Loads, an EAR Program study, takes a novel approach to developing greater understanding of how drivers acquire visual information in order to determine how roadway features can improve or detract from the safety of driving at night. This fact sheet discusses building a dynamic model of driver vision, capturing data on looking and lighting, and identifying some likely activities moving forward.
For this study, researchers have been deploying new technology and developing a new framework within which the variables that affect nighttime driving visibility and driver behavior can be measured and analyzed more accurately. Drivers process data through two visual modes—focal and ambient—at the same time. One danger of nighttime driving is that while focal vision is confined to the narrow, short area lit by headlamps and any overhead lighting, ambient vision, which provides information about speed and direction, is relatively unimpaired. The driver's continued sense of competence in guiding the vehicle masks the danger of diminished focal vision. This study is exploring whether various roadway features and driving conditions affect these two ways of viewing the environment differently.
After the project data are analyzed, FHWA and the research team will convene an expert peer-review panel for a real-world demonstration and model review. On the basis of the expert review and additional data collected, the investigators will revise the driver visual model and formulate directions for continuing research.
The document is available at www.fhwa.dot.gov/advancedresearch/pubs/11033/index.cfm. Printed copies are available from the PDC.