implications on the traveling public and economy. Assumptions on future maintenance activities and cycles must be made in all instances. Where or how are these assumptions made? NEW TERM ON THE BLOCK, LCA While LCCA has been used for decades, Life-Cycle Assessment, or LCA, in a transportation infrastructure context is relatively new. Think of LCA as LCCA with an environmental twist. Per the European Environment Agency (www.eea.europa.eu), LCA is: “a process of evaluating the effects that a product has on the environment over the entire period of its life, thereby increasing resource-use efficiency and decreasing liabilities.” So, where LCCA is looking at the initial and long-term costs of constructing, maintaining, and rehabilitating an asset, LCA looks at the environmental components in much the same way. What materials are used to construct an asset such as pavement, and what are their associated environmental impacts? For asphalt pavement construction, the components are raw materials, transportation, production, and paving operations. During the life of the pavement, what materials are used for maintenance and resurfacing, what continues on page 14 △ Unlike buildings, dams, or other civil engineering structures, highway transportation assets can be challenging due to numerous unknowns. Bridges and pavements are designed based on structural performance life. Today, many bridges are designed for a 100-year life. When the interstate system construction began in the 1950s and 1960s, bridges were designed to last 50 years. Many of those bridges are being replaced or substantially rehabilitated. Can engineers take what those 50-year-old bridges have taught us and translate it into today’s 100-year designs? This uncertainty highlights the need for continuous improvement and innovation in our design and construction processes. Like bridges, the early pavements on the interstate system were based on 20-year traffic projections using the common construction materials of the day—asphalt concrete and jointed concrete pavement. By reviewing current records, we can see how many pavements that were constructed early in the interstate system period are still in place. Many asphalt pavement sections around the U.S. and Virginia are still performing. They may not have the original surface, but routine maintenance has restored their functional characteristics and, in some instances, increased their structural capacity. Many miles of pavement have been in service for 50 or 60 years, two and a half or three times longer than ever designed. This longevity and the lessons we can learn from it should be reflected in an LCCA, emphasizing the value of historical data in enhancing our initial designs. COMMON DEFINITION FOR LCCA The Federal Highway Administration (FHWA) has promoted using LCCA on projects for several decades. Per the FHWA website: “FHWA promotes Life-Cycle Cost Analysis (LCCA) as an engineering economic analysis tool that allows transportation officials to quantify the differential costs of alternative investment options for a given project. LCCA can be used to study either new construction projects or to examine preservation strategies for existing transportation assets.” Chapter 3 of the 1993 “Guide for the Design of Pavement Structures” is devoted to economic analysis in project selection. Factors such as initial cost, analysis period, maintenance schedules, salvage value, and discount rate are outlined. In 1998, FHWA issued an interim guidance document on “Life-Cycle Cost Analysis in Pavement Design.” Since then, many probabilistic and deterministic cost analysis tools have been developed. In recent years, tools such as RealCost have been expanded to understand better the impacts of construction duration and maintenance cycles and their Life-Cycle Cost Analysis, or LCCA, is an approach that evaluates various viable options for the most economical solution. This economic analysis approach considers the initial costs associated with a project and the costs during an asset’s life until the end of its usefulness. When looking at various options, LCCA is a tool to aid in determining which option to select. It’s important to remember that if all other factors are equal, then the lowest LCCA for a project may be the determining factor. However, seldom are all factors equivalent. Considering all factors, not just the cost, is crucial when conducting a comprehensive LCCA. The future performance of an asset may be assumed based on past data or future predictions. With some assets, historical data, design approaches, and specified maintenance/rehabilitation schedules and activities aid in predicting future costs. However, with others, the future is much more uncertain. Figure 1: LCA Concept as outlined at the Pavement LCA Conference in Illinois. MORE THAN MEETS THE EYE: UNDERSTANDING LCCA AND LCA VAASPHALT.ORG 13
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