Many legal and institutional issues need to be resolved before introducing performance-based contracting methods focusing on performance of roads in maintenance phase into Japanese public procurement, which adopts an input-based payment system. This paper identifies performance-based, performance warranty, comprehension, continuity and long term as the concepts constituting these methods, and examines the multiple effects of these methods and the relations between these effects and concepts from the reviews of contracting practices all over the world. Cost reduction for a road agency and benefit increases for users can be achieved by introducing the concepts into road maintenance management under any implementation. This paper proposes applying the Plan-Do-Check-Act cycle with a review function for business processes, as a road maintenance management cycle. Specific methods for improving business processes are also proposed. These proposals can also be indispensable preparations for introduction of performance-based contracting.

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 The purpose of this study is to clarify the characteristics of the Japanese standard system by comparing it to other nations' systems. A literature search on systems was primary source of material for this study. Interviews on some systems were also conducted. The comparison clarified the characteristics of the Japanese standard system as follows. It does not have strong binding power for a client since it does not clearly set out the obligation to review a design. It does not have strong binding power for a design consultant and a contractor since a client does not verify if they have carried out a rigorous check. It does not give a design consultant and a contractor any incentives to comply with it and does not give a checker any disincentives not to comply with it. Hence it does not ensure that the players review or check.

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 When a deterioration of infrastructures has proceeded, they are repaired in order to recover their states. Regarding infrastructures, enormous records of repair have already accumulated. However, as a matter of fact, there are few research results of the post quantitative evaluation of repair effects. In this paper, targeting RC slabs, the authors (1) carry out the statistical deterioration prediction using visual inspection data, and (2) propose the method of the post evaluation of repair effects based on the deterioration prediction result. The mixed Markov deterioration hazard model and its hierarchical Bayesian estimation are employed as concrete model and estimation method, and the heterogeneity between deterioration processes before and after the repair in each RC slab is evaluated quantitatively. In addition, through the relative evaluation of deterioration rates between before and after repair, the post evaluation of repair effects is conducted. Furthermore, the proposed method is applied to the visual inspection data and the repair data of RC slabs in order to verify its effectiveness empirically.

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