Preventive maintenance techniques are considered useful in extending the life of a pavement if applied at the right time. Discussed here is a framework for a process that can be used to select the proper maintenance strategies for different distress types in asphalt pavements, depending on traffic level and environment. Maintenance treatments addressed include only crack seals, fog seals, slurry seals, microsurfacings, chip seals, thin asphalt concrete overlays, and other thin surface treatments. Types of distress considered include roughness, rutting, fatigue cracking, longitudinal cracking, raveling, weathering, and bleeding. Decision trees, based on the authors' experiences, are presented to illustrate the process in selecting appropriate maintenance treatments. A framework for evaluating the cost-effectiveness of the various maintenance treatments is presented. Existing methods for evaluating cost-effectiveness of maintenance are discussed together with their strengths and weaknesses. An example of cost-effectiveness for different maintenance treatments is also briefly presented.

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America's highway system is critical to meeting the mobility and economic needs of local communities, regions, and the nation. Developments in research and technology-such as advanced materials, communications technology, new data collection technologies, and human factors science-offer a new opportunity to improve the safety and reliability of this important national resource. Breakthrough resolution of significant transportation problems, however, requires concentrated resources over a short time frame. Reflecting this need, the second Strategic Highway Research Program (SHRP 2) has an intense, large-scale focus, integrates multiple fields of research and technology, and is fundamentally different from the broad, missionoriented, discipline-based research programs that have been the mainstay of the highway research industry for half a century. The need for SHRP 2 was identified in TRB Special Report 260: Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life, published in 2001 and based on a study sponsored by Congress through the Transportation Equity Act for the 21st Century (TEA-21). SHRP 2, modeled after the first Strategic Highway Research Program, is a focused, timeconstrained, management-driven program designed to complement existing highway research programs. SHRP 2 focuses on applied research in four focus areas: Safety, to prevent or reduce the severity of highway crashes by understanding driver behavior; Renewal, to address the aging infrastructure through rapid design and construction methods that cause minimal disruptions and produce lasting facilities; Reliability, to reduce congestion through incident reduction, management, response, and mitigation; and Capacity, to integrate mobility, economic, environmental, and community needs in the planning and designing of new transportation capacity.

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The Second Strategic Highway Research ProgramAmerica's highway system is critical to meeting the mobility and economic needs of local communities, regions, and the nation. Developments in research and technology-such as advanced materials, communications technology, new data collection technologies, and human factors science-offer a new opportunity to improve the safety and reliability of this important national resource. Breakthrough resolution of significant transportation problems, however, requires concentrated resources over a short time frame. Reflecting this need, the second Strategic Highway Research Program (SHRP 2) has an intense, large-scale focus, integrates multiple fields of research and technology, and is fundamentally different from the broad, mission-oriented, discipline-based research programs that have been the mainstay of the highway research industry for half a century.