Probabilistic Characterization of Life-Cycle Agency and User Costs: Case Study of Minnesota

Abstract

Life-cycle cost analysis (LCCA) is a commonly used approach by pavement engineers to compare the economic efficiency of alternative pavement design and maintenance strategies. Over the past two decades, the pavement community has augmented the LCCA framework used in practice by explicitly accounting for uncertainty in the decision-making process and incorporating life-cycle costs not only to the agency but also to the users of a facility. This study represents another step toward improving the LCCA process by focusing on methods to characterize the cost of relevant pay items for an LCCA as well as integrating costs accrued to users of a facility caused by pavement–vehicle interaction (PVI) and work zone delays. The developed model was implemented in a case study to quantify the potential implication of both of these components on the outcomes of an LCCA. Results from the construction cost analysis suggest that the proposed approaches in this paper lead to high-fidelity estimates that outperform current practice. Furthermore, results from the case study indicate that PVI can be a dominant contributor to total life-cycle costs and, therefore, should be incorporated in future LCCAs.

Probabilistic Life-Cycle Cost Analysis of Pavements Based on Simulation Optimization

“…User cost is related to pavement impacts on fuel consumption through pavement-vehicle interaction (PVI), and traffic delay cost by work zone closures. Total delay cost is quite small compared with PVI cost given a whole analysis period, so at this time the user cost in this model only considered fuel consumption caused by PVI ( 13 ). Future work should expand this to other forms of user cost.…”

“…Equation 8 describes the user cost, which is related to traffic volume and performance condition. Since the analysis focuses on a single segment, user cost can be regarded as a linear function of IRI by coefficient α ( 13 ). Equation 9 describes the relationship between pavement types m t and available treatment actions N t at year t .…”

“…Another important methodological consideration for pavement LCCA is the determination of a treatment schedule, which includes treatment actions and timing. The simplest approach is to use a prescribed schedule ( 2 , 3 , 10 , 13 ). Prescribed schedules are usually based on expert-based decision trees or previous engineering experience ( 14 ).…”

Implementing life cycle cost analysis in road engineering: A critical review on methodological framework choices

“…In contrast with deterministic models, probabilistic LCCA does account for the uncertainty of individual input variables through random sampling and on the basis of a frequency probability distribution [21,81]. The first step in performing a probabilistic LCCA is to identify uncertain input parameters and to develop probability density functions for these parameters [102].…”

“…Others propose an LCCA based on optimizing performance and available funds [14]. Another type of analysis that is proposed, is a new probabilistic simulation-optimization LCCA that takes into account the uncertainty of the input parameters [5,21,22]. Hence, it is important to analyse the parallelism of these models and how they are applied in road projects.…”