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3 1.1 Background Highway assets play a major role in the transportation of goods and public mobility. High- ways are essential to our nationâs economic and social growth; however, the condition of the highway infrastructure in the United States is being compromised because of its age and limita- tions on the funds available for preservation. To provide the highest level of service possible and retard deterioration of highway infrastructure, proactive and cost-effective maintenance strate- gies are needed, so that the right treatment is applied to the right asset at the right time. Budget constraints and other factors often delay maintenance treatments, and the consequences of delayed maintenance often are not fully considered in the funding allocation process. In part, this occurs because of the lack of a practical method to objectively quantify the consequences of delaying maintenance. In this study, delayed maintenance was defined as work needed to preserve the highway sys- tem but postponed in the agency-defined maintenance program. When striving to establish the value of timely maintenance, highway agencies frequently are called upon to answer questions such as: 1. How do maintenance strategies affect asset performance and service life? 2. How can the consequences of delayed maintenance on highway assets be quantified? 3. How are the effects of delayed maintenance best communicated? Establishing the short-term and long-term effects of differing maintenance strategies on asset performance can be challenging, particularly when analyzing a single asset group in a single high- way agency. The task becomes even more challenging when the assessment must generate compa- rable results across various asset groups and heterogeneous managing agencies. Some generalities can, however, offer a starting point. Factors to consider when establishing a connection between maintenance and asset performance include: â¢ Current asset condition; â¢ Timing of maintenance activities; â¢ Changes in asset condition created by the maintenance activity; â¢ Asset design features (e.g., materials, functionality, reliability); â¢ Performance measures; â¢ Communication needs (e.g., with funding entities); â¢ Expected levels of service; â¢ Mechanisms of deterioration over time; â¢ Expected asset service life; and â¢ Factors affecting the remaining asset service life (e.g., traffic volumes and loads, environmental conditions). C H A P T E R 1 Introduction
4 Consequences of Delayed Maintenance of Highway Assets 1.2 Objective and Scope The objective of this project was to provide a set of procedures to quantify the consequences of delaying maintenance of the highway infrastructure. The proposed procedures describe pro- cesses, methods, and analytical tools to quantify the consequences of delaying maintenance for specific highway asset groups (i.e., pavements, bridges, culverts, guardrails, lighting, pavement markings, and signs). The goal of creating these procedures is to provide a practical approach with an adaptable framework that highway agencies can use to support better maintenance funding decisions concerning highway asset groups and to communicate that information to decision makers. It is recognized that each highway asset group has unique characteristics in terms of maintenance policies, condition assessment, deterioration rates, service lives, and life- cycle costs. The procedures consider the highway agencyâs preservation policy, performance measures, available asset condition, maintenance records, performance models, and timing of maintenance activities. The framework takes into account the strengths of pavement and bridge management sys- tems as useful analytical tools, but recognizes the data limitations of the other groups of assets. Procedures are developed for each highway asset group with the intent that they can be adapted to an agencyâs specific policies and practices. Each highway agency will need to adapt and apply the procedures by using the methods and tools that best fit the agencyâs preservation policies, resources, and performance standards. 1.3 Research Approach The research for NCHRP Project 14-20A builds on previous research work and uses avail- able methods to assess the effects of preservation programs for various maintenance scenarios. The research study was divided into two phases. In Phase I, procedures were developed for pavements and bridges. In Phase II, procedures were prepared for culverts, guardrails, lighting, pavement markings, and signs. The researchers conducted an information review and online surveys to collect informa- tion relevant to the current state of practice. Previous research conducted under NCHRP Project 14-20 also was reviewed. The information review was useful in the development of the online survey. The research team then conducted focused phone interviews with selected state highway agencies based on the findings from the information review and the online survey responses. The specific objectives of the phone interviews were: â¢ To identify reports and other documents relevant to the project that were not available through the regular literature review and sources; â¢ To identify whether state highway agencies can provide data usable in preparing realistic examples to illustrate the application of the procedures; and â¢ To gather practical recommendations related to the ease of implementing the procedures including data, performance models, and analytical tools. Merging insights from the telephone interviews with information from the literature reviews, the research team developed frameworks for the individual asset groups (i.e., pave- ments, bridges, culverts, lighting, guardrails, pavement markings, and signs). Next, the team developed and analyzed a series of delayed maintenance scenarios using feedback from the prior work. Decision-support and analytical tools (e.g., a pavement management system [PMS], bridge management system [BMS], and the National Bridge Inventory Analysis System [NBIAS]) were used to perform the delayed maintenance scenario analyses described in this report.
Introduction 5 1.4 Organization of this Report NCHRP Research Report 859 is organized into four chapters. This introductory chapter pro- vides background information, presenting the research objectives, scope, and approach, and the organization of the report. Chapter 2 describes the conceptual approach and explains the general framework recommended by the research team to quantify the consequences of delayed mainte- nance. Chapter 3 describes the procedures developed for pavements, bridges, culverts, guardrails, lighting, pavement markings, and signs. Chapter 4 provides a summary and recommendations for future research. Appendix material not printed with the report provides additional information on the research project. The information initially contained in Appendices A and B has been incorporated in the report, and these appendices have, therefore, been deleted. Appendices C through I, which pro- vide detailed procedures and examples for the highway asset groups described in Chapter 3, can be downloaded from links on the report webpage, available at www.trb.org by searching âNCHRP Research Report 859â.