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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Public Roads - March/April 2005

March/April 2005
Issue No:
Vol. 68 No. 5
Publication Number:
Table of Contents

Training Update

New NHI Course Helps Maintain Ancillary Roadway Structures

The National Highway Institute (NHI)

The Nation's highways need smooth pavements, secure bridges, and well-designed interchanges to ensure safe and efficient travel. Also important are the ancillary or auxiliary structures, such as traffic signals, overhead highway signs, and high-mast lighting fixtures that help keep highways well-lit, well-marked, and free of congestion. The structural supports for these roadway components, however, increasingly show signs of wind-induced vibration, fatigue, and collapse. The increasing rate of failures is due in part to inadequate design specifications prior to 2001, when the American Association of State Highway and Transportation Officials introduced the fourth edition of Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals (LTS-4-I1).

To inform officials at State and local transportation agencies about updated and improved installation, inspection, and maintenance procedures, the Federal Highway Administration (FHWA) published Guidelines for the Installation, Inspection, Maintenance, and Repair of Structural Supports for Highway Signs, Luminaires, and Traffic Signals. The procedural guidelines described in the document are important for ensuring the adequate performance of older and fatigue-susceptible structures. To help State and local transportation officials establish inspection programs that comply with these guidelines, FHWA's National Highway Institute (NHI) recently introduced a course titled Inspections of Ancillary Highway Structures (#130087).

In one of NHI's newest course offerings, transportation professionals can learn new, nondestructive methods for inspecting ancillary highway structures like these traffic signals and high-mast luminaire (right).

NHI developed the course, which uses the FHWA guidelines as its foundation, for field inspectors, construction supervisors, maintenance and other technical personnel, and structural, material, and traffic engineers. The information also should be helpful to those who work with the design and specification of ancillary structures.

Upon completing the course, participants will be able to recognize appropriate nondestructive testing techniques, such as dye-penetrant, magnetic particle, and ultrasonic testing, that can help them locate and identify various types of internal defects without compromising a structure's surface integrity. Participants also will learn how to identify the factors that lead to corrosion on ancillary structures and determine the most appropriate mitigation methods. In addition, they will be able to identify common visible defects in welds and base-anchor bolt installations. They also will be able to define the severity of any observed defects in accordance with FHWA guidelines.

The course is offered in a classroom environment and includes a variety of teaching tools, such as sample structural photos and materials showing different types of defects. Although private sector firms have provided similar training in the past, the NHI course is a more comprehensive program that reflects an increasing national awareness of the failure of ancillary structures and the need to inspect and maintain them.

For more information on the technical content of the course, contact Doug Edwards, a structural engineer with the FHWA Resource Center in Atlanta, at 404–562–3673 or To schedule a course, contact Danielle Mathis-Lee at 703–235–0528 or