This paper addresses the need for extending the research perspective of infrastructure planning, and claims that “risk analysis” should be incorporated into the system perspective of planning science. Qualifications of “risk analysis” for infrastructure planning are discussed, and three key concepts, “quality of information, ” “quality of planning” and “quality of life” are suggested. By use of the concepts. six papers which constitute this special issue are systematically classified and their values, uniqueness, and limits are examined. The paper concludes by referring to future prospects of risk analysis and the possibilitiy and necessity of applying this approach for challenging a planning paradigm shift are discussed.

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This paper makes a critical review of the state-of-the-art of “risk analysis” It is shown that there have been a variety of approaches that have been developed under the category of what we may call “risk analysis”. An attempt is made to compare a set of approaches based on risk analysis which come from different disciplines such as insurance theory, business administration, reliability engineering, medical science, and economics. Their progresses are discussed, and their natures and characteristics examined. The paper concludes by referring to the need for developing a frame of reference at meta-level to support systems-analysis-based planning. Some prospects are suggested to establish the field of risk analysis.

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This paper addresses the need for bringing in “risk analysis”-based approach to planning and management of infrastructure. Given the status-quo of the infrastructure developed in Japan, a shift needs to be made from quantity to quality management; hence the growing need for controlling stability of service level for infrastructure. It is claimed that the proposed perspective of “risk analysis” meets much of the need. A state of the art survey is conducted to review research related to water resources management and highway planning. The paper concludes by referring to future research to be done within the proposed perspective of “risk analysis.”

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We have developed the intuitive evaluation system for reliability of bridges. In this paper, based on this system we propose a bridge maintenance planning process model and discuss its risk structure. First of all, we assess the credibility of the basic system as planning information system. Secondly we point out two types of risk embedded in this planning process, i. e. risk of rejection of the proposed plan and risk of ineffectiveness of the plan. Fianlly we disscuss several countermeasures and risk chain structure.

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Land space use is planned based on the National Land Use Planning Act but unfortunately it does not include water area. Therefore, planning of coastal areas sometimes causes conflicts among related governments and the interest groups. Conflicts among interest groups often results in the failure of plan. The present paper calls this as ‘the failure risk of plan’. Conflict management, however, has not been considered as the matter of planners or analysts. The present paper proposes a planning model to manage the conflict between the central and the local governments in coastal area zonening based on the 2-level N-person Cooperative Game. Numerical example is presented to demonstrate its feasibility by an application to Osaka Bay Areas.

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Risk Management, or reducing loses resulting from uncertainties, has been becoming a great concern in infrastructure planning. This paper addresses the risk that drivers suffer in connection with travel time variation. Two agencies, a road traffic manager and drivers, are considered to severally react against the risk, and a model of Risk Assignment is proposed, which determines traffic manager's action to minimize total drivers' risk. This paper firstly depicts the general framework of risk management in traffic management and then specifys the Risk Assignment problem. Numerical examples are presented in order to refine the formulation of Risk Assignment problem.

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This paper discusses an evaluation problem of the benefit of reservoir under uncertainty. A reservoir has a function of flow stabilization. Since natural stream flow is uncertain, the available water in stream sometimes becomes shorter than water demands and then a drought happens. Constructing a reservoir makes the stream flow stabilized and probability of drought is reduced. We should consider how to evaluate the benefit of stream flow stabilization or reduction of drought probability. In the field of welfare economics, option priceand expected consumer surplus are proposed for estimation of benefit of a project in a risky world. These measures are formulated and examined. The focus of this paper is to find the appropriate way to measuring the benefit of a reservoir through examination of these measures.

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An automated highway routing system on a personal computer has been developed. Inputting topological data including such control points as location of residential developments, parks, shrines, temples, rivers and ricefields, the system gives automatically several candidate highway routes which satisfy design conditions following given skilled engineer's judgements. The system can give routes shown by either freehand lines following spline curves or lines composed with straight lines and circles. The system also has an evaluation system which follows AHP, concordance analysis and cost-benefit analysis.

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Passenger car equivalents reflect an effect of trucks to a highway capacity. A few studies propose an estimation of the PCE on expressways in Japan. However, effects of any geometric factors are not mentioned in these studies. The purpose of this study is to propose a theory on estimation of PCEs introducing an adjusting coefficient of an effect of some geometric factors existed on a long section of an expressway. Verification of this theory applying to the data collected from many detector stations setup about 47km long section on the Tomei Expressway is also another objective of this study. The steeper the upgrades (>3%) and smaller the radii (<600m) at the detector stations, the larger are the estimated PCE values. These expressway sections have lower free speeds and are also recognized capacity bottlenecks by many researchers.

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Road roughness, specially ruts of pavement surface have much influence on safety for auto drivers, spceially motorcycle riders. However, the present judgement standard for pavement repairs in Japan is measured in term of road life span and serviceability and is not considered from the viewpoint of riding safety.
In this paper we investigate the relationship between the rut depth of pavement surface and safety consciousness by motorcycle riders quantitatively through the riding test on rutted roads and the questionnaire survey on safety consciousness of the riders. In conclusion we propose a new judgement standard for pavement repairs.

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In decision making problems on air quality control linear programming and stochastic programming have often been applied. This study focuses acid rain control in North America and proposes five stochastic programming models which in various ways maximize the probability that the acid deposition rate, under given total reductions of SO₂ emissions, does not exceed the maximum allowable wet deposition rate at each receptor. The optimum solution to each model is compared to find the models most suitable for the decision making on acid rain abatement.

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The purpose of this study is to discuss the design of street signs in order to support creating space which is highly evaluated from a cultural point of view. For that purpose, we estimated some street signs on traditional and modern districts in Kyoto, in the use of psychological data that are aquired in the questionnaire survey.
In that study, the signs to be investigated were selected from four streets in Kyoto. Respondents were requested to answer their impression which they received from that signs. We estimated streets signs and the relation between signs and buildings in the use of aggregation results. Consequently we could find the following concepts of the streets. That is, “The order of traditional districts” on Pont-cho Street
“The subordination to townhouse” on Kamishichiken Street
“The free competition of information” on Kiyamachi Street
“The coexistence between architecture and sign” on Kitayama Street

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It is one of the purposes to select or discard different geographical information and make it multipurpose based on the extraction and recognition of information existing in original maps by geographical information system (GIS). This study describes recognition elements of map symbols which are not affected by scale. Every map symbol is separated into single-image and separated-image to extract recognition elements and also clustering criterion is decided by the necessary recognition elements in the clustering. Therefore, 50 kinds of map symbols can be extracted and recognized with the reocognition elements and clustering criterion proposed in this paper.

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A method of automatic calculation of approximations of parameters of photographs with respect to any model or object coordinate system is discussed. This method realizes the followings: (1) Semi-automatic orientation of photographs…It is very useful for digital-image-based-plotters which require easy manipulation for the people who are not familiar with photogrammetry. 2 Close-range photogrammetry without control points (3) Camera calibration without control points. The procedures are based on relative orientation of independent models by the linear coplanarity condition and unique decomposition of obtained rotation matrices to angular elements. These models are connected to form a global model. The method is validated by two experiments; a relative orientation test of a pair of photographs and a camera calibration test without control points.

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This paper deals with a model system for stochastically represent performance of road infrastructure. This system consists of two submodels which represent 1) deterioration and 2) repair intervention behaviors of a road agency. These are developed based on the concepts of failure time models (FTMs) using repair history, truck traffic volumes, pavement condition and age as explanatory variables. The future road performance is predicted based on the probabilities obtained by these submodels and the cohort survival concepts. Finally, sensitivity of expected pavement condition, reliability and maintenance costs to different budget levels and policy alternatives such as budgeting scenarios and priority criteria is evaluated.

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