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Highway maintenance and rehabilitation (M&R) planning is a multifaceted decision-making process that requires the consideration of multiple but often conflicting objectives. Traditionally, state highway agencies (SHAs) have focused on maximizing the condition of a pavement network or minimizing agency costs needed to keep the network at an acceptable physical and functional level of service. However, other objectives like minimizing the road user costs and greenhouse gas (GHG) emissions are seldom factored into the M&R decision-making process. In this paper, a mixed integer program that accounts for these three objectives is presented. The proposed model is then implemented on a subset network in Texas consisting of 100 pavement sections. The results demonstrate the Pareto-optimal relationships that exist between the road condition improvements, road user costs, and GHG emissions. Notably, there is a positive relationship between condition score improvements and the observed marginal GHG emissions from the case network implementation. Furthermore, this network's results indicate that GHG emissions from materials and construction contribute to the most significant proportion of the total estimated GHG emissions. The results of the sensitivity analysis confirm the observed trends in the network case examined and provide valuable insights concerning the impact of variability in the budget size. The principal contribution of this study is in providing an approach for highway decision-makers to perform trade-offs in road condition improvements, road user costs, and GHG emissions of alternate pavement M&R programs or policies. [ABSTRACT FROM AUTHOR]

Current materials and construction specifications for pavement preservation treatments are predominantly prescriptive and rarely correlate the initial quality of the treatment to its future performance. As a result, it is difficult for highway agencies to account for the performance lost or gained due to differences between the as-designed treatment and as-constructed treatment. Also, these specifications may not incentivize contractors to focus on factors that affect the treatment's long-term performance. To account for these limitations, this paper provides a simulation-based performance-related specification (PRS) methodology for pavement preservation treatments, with application to thin hot-mix asphalt (HMA) overlays. Through performance prediction models and lifecycle cost analysis, this methodology determines pay factors based on the probability distributions of the total lifecycle costs of the as-designed and as-constructed treatments and the unit bid price. The developed PRS methodology was applied to four Long-Term Pavement Performance sections in Texas, Idaho, Florida, and New Jersey that received thin HMA overlay treatments. These case studies demonstrated the applicability of the developed methodology and provided insights into the relationships between the initial quality of thin HMA overlays and expected pay factors. [ABSTRACT FROM AUTHOR]

With an increasing emphasis on sustainable planning, highway decision makers need to shift their focus from developing a cost-effective highway program to developing a more comprehensive sustainable highway program. It includes incorporating the three components of sustainability, namely economics, the environment, and social equity. Studies in the literature have primarily focused on economic and environmental objectives. However, there are limited studies incorporating social equity in highway maintenance and rehabilitation (M&R) programming. Additionally, a review of the existing literature indicated that although studies have focused on single or dual objectives of sustainability, the existing literature failed to address all the three components of sustainability simultaneously. Accordingly, this study aimed to address this issue by proposing an M&R budget allocation model for developing a sustainable highway asset management plan that concurrently focuses on all the three objectives of sustainability. The proposed model assists decision makers with a range of potential decision alternatives that address multiple sustainability objectives. The proposed model was applied to a case-study example on a road network in Texas. The findings from the case study indicated that decision makers can implement sustainable M&R programs that can efficiently achieve social equity objectives without specifically compromising the environmental and economic objectives. [ABSTRACT FROM AUTHOR]