In this paper, the long-term environmental impact on a waste treatment project in developing countries was evaluated, and several waste treatment scenarios were compared to discover which waste tr eatment would be more effective, both economically and environmentally, in the intermediate treatment and the final treatment process. Specifically, we evaluated the environmental impact for a waste treatment project in the Bangkok Metropolitan area in Thailand, and estimated the long-term treatment cost and environmental load (CO₂ and CH₄ emissions) quantitatively regarding assumed waste treatment scenarios. And by utilizing the monetary value of CO₂ emissions intensity, we incorporated the environmental load as an environmental cost. As a result, as for the treatment cost, the baseline scenario modeling the current waste treatment project was found to be the least expensive, while the scenario constructing incineration plants and facilities with CH₄ was found to be the most expensive. As for the environmental load, on the other hand, the scenario constructing incineration plants and facilities with CH₄ was found to have the least load, while the baseline scenario was found to have the most loads. Also, in the Bangkok Metropolitan area, the scenario constructing facilities with CH₄ was found to be effective in both treatment cost and environmental load from the viewpoints of total cost and the environmental impact index. Furthermore, it was found that uncertainties regarding the amount of waste, monetary value of CO₂ emissions intensity, and the evaluation period greatly influenced the estimation of the treatment and environmental cost in the waste treatment project.

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 The objective of present study was to develop the a nxiety scale for natural disaster, and to examineits reliability. We developed the 14 items for the anxiety scale based on anticipated damage of Nankai earthquake in Ehime prefecture. The subjects consist of 391 people in Yawatahama city, Ehime prefecture. Firstly, we analyzed the latent factors which influenced the anxiety for natural disaster by using the factor analysis method. Secondly, we cal culated Cronbach's coefficient alpha. The result of the factor analysis confirmed the three factors such as "anxiety for lifeline damage", "anxiety for second ary disaster" and "fear for others". Cronbach's coefficient alpha for each factor showed the high interna l consistency reliability. We considered that each factor could prove to be a valuable tool for researc h about the person's anxiety for natural disaster.

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 In our country, many infrastructures built in a highly economic growth period will be creaky. Therefore a need exists for a large amount of expense for maintenance and repair. On this account, application of asset management technique and budget for maintenance depending on an need are extremely important. Differences of consciousness structure of inhabitants that use frequency are high and low related to road maintenance management are analyzed, in case study of a tunnel coned off for four months by some troubles. In analysis results, persons show approval increase of maintenance expense, who feel that "maintenance administrative expense" is low and "satisfaction of administrative service related to road maintenance" is high. Whereas persons damaged by suspension of traffic disapprove expense increase. This result is totally reverse to original expectation and a very important for maintenance management policy.

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 Not only developments of new social capital but also effective management of existing social capital stock is indispensable for sustainable finance of public governments. After constructing public facilities, maintenance procedures of the facilities are started and after-assessment of the project is conducted according to each institution of public works. The paper deals with these two kinds of management from the aspect of improving function of public facilities through case-studies of Dam management in Tochigi prefecture. First, the present conditions and problems in them are reviewed. Second, case-studies of different types of assessment and planning for improving functions of existing dams using stocked management data are represented and compared. Finally, the basic idea of after-assessment for improving functions of existing dams, and some aspects to have to be improved in the present after-assessment system of them are discussed.

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 National land policy should be examined in consideration of diversification of values and life-style today. Therefore, in order to implement infrastructure management with great satisfaction, we carried out a survey and analyses of the values of people who prefer the countryside. The survey was carried out in Ono-machi, Fukushima, Nichinan-cho, Tottori and Tarumizu-shi, Kagoshima.
 The results reveal values of people who moved into the countryside. When they consider the move, they make much of quality of the work and spare time. When they choose where they move into, they consider living environment and local communities in particular. After moving into the countryside, a family, living environment and human relations with neighbors become important to them.
 Therefore, the high-quality workplace in their neighborhood, superior living environment and good human relations with neighbors are important. In addition, providing information on living environment and local communities of towns in the countryside helps people to move into those towns.

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 After revision of the Railway Business Act in 2000, the abolition of the local railway has increased in Japan. However, continuing activities by people living along local line has been focussed in recent years. Moreover, a lot of local railway's business are obtaining the subsidy from the municipality where railway route is located. When the government puts out the grant to the company, it is necessary to have the accountability for the peoples. This research is focused on the value of the local railways for residents are measured, and an economical value of that is estimate by using the Contingent Valuation Method. As for the route for analysis in Nagano, Bessho-line(Ueda), Yashiro-line(Nagano) and Kamikohchi-line(Matsumoto) were chosen. Moreover, policies of each municipality to these routes are evaluated by using these values.

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 In a previous study, we classified the communicatio n errors at construction sites as faulty intention and message pattern, inadequate channel pattern, and faulty comprehension pattern. This study seeks to evaluate the degree of risk of communication errors and to investigate differences among people in various job positions in perception of communication error risk . Questionnaires based on the previous study were a dministered to construction workers (n=811; 149 adminis trators, 208 foremen and 454 workers). Administrators evaluated all patterns of communication error risk equally. However, foremen and workers evaluated communication error risk differently in each pattern. The common contributing factors to all patterns wer e inadequate arrangements before work and inadequate confirmation. Some factors were common among patterns but other factors were particular to a specific pattern. To help prevent future accidents at construction sites, administrators should understand how people in various job positions perceive communication errors and propose human factors measures to prevent such errors.

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 Compared to the late 20^th century, the Japanese construction industry has drastically changed its business methodology, outlook and approach in response to global issues and the incredible advances in technology. Such influences, non-exhaustively include the; WTO Government procurement agreement, updating conditions of tendering and contracting, client demands for cost reduction and the rapid penetration of ICT (Information and Communication Technology) into modern society. These days, the significance of controlling Quality, Cost and Time (the so-called QCT) has been recognized as an eternal-triangle by almost all countries, Government organizations and the private sector. However, as the construction industry is exposed to , and influenced by, more and more internal and external dynamic factors, continued reliance on managing and controlling QCT elements on their own is no longer adequate in meeting the growing demands and expectations, and as such control of additional management elements is now essential to avoid problems, or minimize their potential impacts should they occur.
 This paper utilizes the results of a survey carried out amongst construction managers and consultants in Japan and overseas to develop a spatial network that defines the interaction of management factors as a weighted graphical model. The calculated closeness centrality index of the developed management network model is adopted to identify the initialelement hierarchy, which is then further analyzed using the minimum distance of independent relationships of management elements (Warshall-Floyd algorism methodology), to identify the optimum potential hierarchy for effective construction management. A key result of the analysis is the significance of "Human Resource" in the construction industry management element hierarchy alongside the traditional QCT elements.

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 Recently, an endemic operetion rules for a various bidding-contract system has been tried on local public works in japan. Overall-Evaluaton system expected for improved quality and anti-dumping, however that treading cost is relativery high, and questionable benefit of that system. In this paper an attempt is made to analysis an impact of bidding-contract system for each constructer's management by developing new simulation model, clarified some of characteristic of Overall-Evaluation system.

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 Because of the aging of road facilities and limited budget for the maintenance of them, many local gov ernments in Japan are establishing a maintenance management plan in order for the preventive maintenance. However, such plans mainly focus on each road facility individually. The road network however functions by connecting with other facilities and the maintenance of road facilities should be planned by considering these network effects.
 Based on above background, this study attempts to d evelop an integrated asset management technique for road facilities by simultaneously dealing with pavements, bridges and dangerous slopes. The method to evaluate the imp ortance and necessity of individual road facility by the risk management technique is first developed, and all roa d facilities are unitarily compared based on this method. We further established the method to reduce the risk efficiently by ide ntifying the section which may reduce the total risk of road network by the maintenance. The proposed method is verified by applying to 4 routes in Gifu Prefecture. The result clearly shows that the rationality of the method reducing the risk the whole road network.

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 Public procurement system such as Overall-Evaluation dynamically has been changed on local public works in Japan. However some characteristics of Bidding-Strategy and procurement system have not enough clarified. This paper attempt to analysis for a syatem dynamics and mechanisum of Overall-Evaluation by developing new simulation model focused on Bidding-Strategy, to propose some improvement scenario.

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 To improve the safety and security of driving while coping with today's stagnant economy and frequent natural disasters, road slopes should be appropriately managed. To achieve the goals, road managers should establish project priority evaluation methods for each stage of road slope management by clarifying social losses that would result by drops in service levels. It is important that road managers evaluate a project priority properly to manage the road slope effectively. From this viewpoint, this study proposed "project priority evaluation methods" in road slope disaster prevention, which use available slope information at each stage of road slope management under limited funds. In addition, this study investigated the effect of managing it from the high slope of the priority by evaluating a risk of slope failure. In terms of the amount of available information, staged information provision is needed ranging from macroscopic studies, which involves evaluation of the entire route at each stage of decision making, to semi- and microscopic investigations for evaluating slopes, and microscopic investigations for evaluating individual slopes. With limited funds, additional detailed surveys are difficult to perform. It is effective to use the slope risk assessment system, which was constructed to complement detailed data, to extract sites to perform precise investigations.

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 In recent years, it has been wrestled an investigation and the soil, groundwater contamination measures business (as follows: the environmental restoration project) that purify it and take measures against about pollution of the soil and groundwater led by a private enterprise. Japan has accumulated rich in restoration projects on the environment. The measures requires a hefty cost, it is clear that variety risks, management techniques are required to establish an efficient environmental restoration projects.
 In this paper, comparative study of the generation construction and environmentalrestoration projects, said the basic features of environmental restoration projects and trouble cases residents have been there. The types of features of the project for environmental restoration CM and demonstrated the business. To organize a variety of business risks and illustrates the concept of risk management. In addition, the figure of a management system based on its severity and the relationship between each elements and the business.

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 Within today's infrastructure management, Asset Management systems are becoming a mainstream feature. For region where the risk is low, it is necessary to create a "cooperative road facilities management system". This research both examined and suggested what kind of cooperative road facilities management system should be promoted by the regional society.
 Concretely, this study defines the operational realities of a previous case. It discusses the problem of the road facilities management as a governance. Furthermore, its realization depends on "the cooperation between municipalities", "the private-sector initiative", and "residents participation" .Also, it discusses the problem of human resources for governance. Its realization depends on "the engineers' promotion", and "creation of a voluntary activity of the resident" as a human resources. Moreover, it defines that the intermediary is important because the human resources tied to the governance.
 As a result, the prospect of the road facilities management is shown by the role of the player and the relation among player.

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 It is essential to establish efficient management strategies for existing infrastructure in order to ensure their structural performance during design service lives. In particular, appropriate preventive maintenance should be implemented based on the life cycle cost minimization. Maintenance work for infrastructures has been carried out to assess the present conditions of structure and to quantify the structural performance. As for the appropriate life cycle management and minimization of lifecycle cost, it is important to evaluate reliability for predicting the future progress of performance degradation. The objectives of this study are 1) to evaluate distribution forms of the deterioration rates based on the Kolmogorov-Smirnov test; 2) calculate the predicted lifetime by using the Monte Carlo simulation; and 3) to predict the deterioration progress and evaluate the influence of deterioration degree on the results of deterioration prediction with the Markov model. As the results, the following conclusions were drawn: 1) distribution forms of predicted lifetime for each facility were confirmed; 2) the differences between the mode and minimum values of the predicted lifetime were guantified; and 3) calculation formulas based on the transition rates were proposed and the relation ship between errors of lifetime predictions based on different deterioration grades.

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 In mountain tunnel construction project, ground condition expected in a preliminary survey and a real condition cause often large deviations. As the result, the large increase of construction cost occurs after the start of excavation. One of the causes of such deviations is the uncertainty of ground information in a preliminary survey. Then, we have studied on the evaluation technique for the uncertainty of ground information and the risk in tunnel digging cost fluctuation caused by the uncertainty (the following, geological risk). In the past study, we paid our attention to the quantity of deviations with an expected digging cost considering the uncertainty and a real cost. However, in geological risk management, it is important to consider the situation that occurs a significant loss when actualized, too. Therefore, conducting a case study in a tunnel that carried out an addition al survey because a bad ground condition which was not foreseen in a preliminary survey appear ed, we studied the geological risk in the preliminary and the additional survey, and compared with construction cost and geological risk. We expected that the probability that the real cost appeared on the risk curve in the additional survey would be higher than the one in the preliminary survey. However, the probability in the additional survey became lower than the one in the preliminary survey when the ground information was added without evaluating uncertainty of ground information appropriately. As the result, we found that it was important to add geological information which is evaluated appropriately, instead of simply adding geological information.

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 It is required that infrastructure should satisfy performance requirement through their service life based on an appropriate life cycle management strategy. Now adays, to determine the maintenance strategy and to consider the appropriate timing and method of intervention, the life-cycle cost (LCC) has been widely used as one of the decision-making indices. However, many factors influence on the estimation of LCC and they have not been adequately investigated. In this paper, the authors have made analytical investigation to quantify the influence of important factors on the results of LCC estimation. Four kinds of mooring facilities are focused; two of them are open-type wharves and the other two are sheet pile type quay walls having different design water depths. Prediction of deterioration progress and performance degradation is made by using the Markov models. The influences of structural sizes, transition probability in the Markov model, design service life, periodic inspection and methods of intervention on LCC were investigated. The influence of those factors has been discussed based on the calculated results of LCC by creating the maintenance scenarios for model mooring facilities.

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 In Japan, various approaches have been taken to ensure the quality of public works or to support the procurement regime of the governmental agencies, as a means to utilize external resources, which include the procurement support service or the construction management (CM) method. Although discussions on these measures to utilize external resources (hereinafter referred to as external support measure) have been going on, as well as the follow-up surveys showing the positive effects of such measures have been conducted, the surveys only deal with the matters concerning the overall effects of the external support measure on the whole, meaning that the effect of each item of the tasks have not been addressed, and that the extent it dealt with the expectations of the client is unknown. However, the effective use of the external support measure in future cannot be achieved without knowing what was the purpose to introduce the external support measure, and what effect was expected on each task item, and what extent the expectation fulfilled. Furthermore, it is important to clarify not only the effect as compared to the client's expectation (performance), but also the public benefit of this measure (value improvement). From this point of view, there is not an established method to figure out the effect of the client's measure to utilize external resources. In view of this background, this study takes the CM method as an example of the external support measure, and proposes a method to measure and evaluate the effect by each task item, and suggests the future issues and possible responses, in the aim of contributing the promotion, improvement, and proper implementation of the external support measures in future.

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 In Japan, the construction management (CM) method has been introduced as a measure to support the governmental agencies, in developing and maintaining local infrastructures, or in executing public works projects in an appropriate manner, etc. The scope of work of the Construction Manager (CMR) of the CM method is specified as work items, in the special specification document for CM services contained in the contract documents, as a reflection of the client's expectations towards the performance of CMR. However, the CM services has been conducted as required on a case-by-case basis, because it is not possible to anticipate the actual construction status in advance, and thus the special specification document does not provide full detail of the scope of work of CMR. In such case, there may be a difference in the way the scope of work in the special specification document is recognized between the client and the CMR, which could make the CM method less effective. Moreover, there is a case in which the role sharing between the client and the CMR is not clearly defined, and both parties may engage in the same task in such case, causing an obstacle for smooth project implementation. For this reason, it is required to prepare the special specification document which clearly defines the scope of work of CMR, by examining the status of application of the CM method in actual project cases, and to improve the practices of the CM method as necessary. In view of this background, this study looks in to the actual project cases using the CM method, for the purpose of clarifying the actual scope of work of CMR for each task item defined in the special specification document, and the role sharing between the client and CMR, in the aim of contributing the promotion of the use and the effective application of the CM method.

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 In this paper, we tried to discuss about the appropriate level of national fund for public works and the appropriate way of raising fund for them that accounts for their macro economic influences. It was then discussed that we have to adopt "austere fiscal policy" during inflation period in order to mitigate the inflation and have to raise fund through tax rather than public bond, and we have to adopt "positive fiscal policy" during deflation period in order to mitigate deflation, and have to raise fund through inland public bond rather than tax increase.

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 The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has adopted the quality-and cost-based selection (QCBS) method in bidding of its public works since 1998. In fiscal year 2009, approximately 99% of MLIT's works were conducted through the QCBS method.
 Since the QCBS method enables the client to contract with both superior cost and quality compared to the traditional cost-based selection, the issue has been how to evaluate the technical capacity of the bidder in individual works.
 In this paper, we have first analyzed the contents and the weight of the quality evaluation criteria for each QCBS types among public works contracted out by MLIT, and identified issues for technical proposals. Next, we have proposed improvements such as setting appropria te score differences based on precise indicators, and introducing methods that evaluates the company's construction capability of public works.

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 Recently, several issues are pointed out, such as dangou and extremely low bidding price that may cause the insufficient quality of infrastructures. First, counter measures taken by MLIT(Ministry of Land, Infrastructures, Transport and Tourism) were analyzed. Then, supposing that the minimum bid price will be taken as winner, bidding model was constructed to find out the influence of number of bidders to bid rate in public works. The model was calibrated and validated using the tender data of Kanto Regional Development Bureau, MLIT. Using the model, it was applied to the analysis of the influence of Standard MinimumPrice for Investigation. The constructed model shows good performance.

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 About 70% of local governments in Japan, endeavored to introduce overall evaluation bidding method for their public works in 2011 and each authority ordered one or some projects in according to the new bidding process.
 That is, their enforcement was an only trial level and they say that the reason why is long-term procedure and heavily administrative load of the system.
 The author think that such burden has relationship of human affairs of local govern ments, practical problems on kinds and price of constructions and the officers' experience on the new bidding method.
 The aim of this study is to analyze such problems among the officers' profession, posts and experience of administrative matter by statistical data, questionnaire and hearing to the officers.
 The result could indicate that a group of small local governments uses the method appropriately and that another group of medium-sized rejects to increase more contracts in according to the new bidding system because of unbalance between the stuffs' ability and order quantity of public works.

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 In view of the necessity for efficient implementation of public works projects, it is expected to utilize advanced technical skills of private firms, for the purpose of reducing project costs, improving performance and functions of construction objects, and reducing work periods, etc.
 The design-build system is a method to order design and construction as a single contract, including design of structural forms and main specifications of the construction object. This is a system in which high techniques of private firms can be utilized, as a means to ensure qualities of design and construction, rational design, and efficiency of the project.
 The objective of this study is to examine the use of a method to form a consortium of civil engineering consultants and construction companies, as it is an issue related to the implementation of the design-build method. Furthermore, by studying various forms of consortiums to be introduced in future, it proposes procedural items required to utilize this method, during the bid and after signing a contract, such as the estimate submission from the civil engineering consultants etc.

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 FIDIC conditions of contract are used in many cases as general conditions for public works funded by Japanese yen loan, but there are cases where the particular conditions are written as to add some special clauses or change some clauses of FIDIC general conditions based on their own current contract conditions and customs, which will lead to restriction of rights and duties of the Engineer and Contractor. This paper focuses on yen loan projects in Philippine and Vietnam, and describes the actual contract management of FIDIC conditions of contract from the viewpoints such as: a) relationship between Client, Contractor and the Engineer b) claim for rights and contract managements. Based on interviews to parties concerned and literature reviews of public works concerned, contractor's rights are granted relatively wider in yen loan projects compared with locally-funded projects. However, it is also observed that the Engineer's rights are restricted by particular conditions, which is written in line with their own public procurement policies of both countries. Some discussions are added how these local procurement policies affect the implementation of FIDIC conditions of contract, and clarified what are the differences of contract management between both countries.

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 Contractor evaluation methods in Japan's public works procurement, beginning with construction business licensure, going through biennial preliminary firm rating, up to project-by-project prequalification and comprehensive point rating, were developed during the period when public works were mostly procured through designated competitive bidding. It is essential to focus attention on contractor evaluation methods for introducing different types of procurement procedures which enhance the use of technological capabilities held by private businesses. An overall review of contractor evaluation procedures should be conducted in view of the present situation, where the open competitive bidding has become mainly used in combination with comprehensive evaluation, as well as to allow for further diversification of procurement methods. In Western countries, improvements have been made for the past several years in contractor evaluation procedures with more emphasis on "Value for Money." Advanced efforts made by these countries will be useful as a reference for overhauling Japan's contractor evaluation system.
 This study conducts a comparative review of contractor evaluation procedures for public procurement in Western countries such as the United States, the United Kingdom and France by identifying similarities and differences between those of Japan and the above mentioned countries. This reveals that a contractor's technical or professional ability is looked at separately from its economic and financial standing in those countries studied, and there is no case like Japan in which those two factors are integrated into one for evaluation.

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 The aim of this study is to analyze the variation factors of successful bid rate in public works tender using data on MLIT (Ministry of Land, Infrastructure, Transport and Tourism), Kanto Regional Development Bureau. It was revealed that number of bidder and level of minimum price affect variation of successful bid rate based on multiple linear regression analysis.

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 In the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), various approaches have been taken for efficient implementation of public works projects, one of which is the ongoing use of the design-build method on a trial basis, as a means to utilize the technical skills and knowledge of private companies. In 2005, MLIT further introduced the a dvanced technical proposal type, a kind of the comprehensive evaluation method, as part of its efforts to improve tendering and contracting systems. Meanwhile, although the positive effect of the design build method has been reported, it has not been widely published, which may be one of the reasons that the number of MLIT projects using the design-build method is declining year by year.
 In this context, this paper discusses the result and review of the study concerning the extent of flexibility allowed for the process and design (proposal) of public work projects, and the follow-up surveys of the actual test case projects, conducted as basic researches to examine the measure to expand and promote the use of the design-build method. The study objects were selected from the tunnel construction projects using the shield tunneling method for developing the common utility duct, and the bridge construction projects ordering construction of supers tructure work and substructure work in a single contract. In providing the result and review of the studies, the structures and the temporary installations were separately examined, and effectiveness and adaptability of the design-build method was discussed for each, respectively.

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 Japanese PFI Law was enacted in Japan in 1999. In these eleven years almost all PFI projects were for buildings, while the infrastructure projects were only about 5% in total. Regarding to the road projects that have been managed by the government, there are various bottlenecks for the implementation of PFI. The purposes of this paper are firstly to investigate the time series trend of the PPP projects in the wor ld, secondly to make international comparative study of the PPP-related institutions, and thirdly to propose the desirable improvements of the Japanese institution in many countries. The key issues of the proposal are the support systems for the risk management by the government which squares the rationale and transparence and the deregulation. Finally introduction of PFI scheme into the toll roads which managed by the public corporations of local governments are proposed as a first step in Japan.

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 The most characteristic trend on bidding and pricing behavior distinction in recent years is the increasing number of bidders just above the criteria for low-price bidding investigations. The contractor's markup is the difference between the bidding price and the execution price. Therefore, the contractor's markup is the difference between criteria for low-price bidding investigations price and the execution price in the public works bid in Japan. Virtually, bidder's strategies and behavior have been controlled by public engineer's budgets. Estimation and bid are inseparably linked in the Japanese public works procurement system.
 The trial of the unit price-type estimation method begins in 2004. On another front, accumulated estimation method is one of the general methods in public works. So, there are two types of standard estimation methods in Japan. In this study, we did a statistical analysis on the bid information of civil engineering works for the Ministry of Land, Infrastructure, and Transportation in 2008. It presents several issues that bidding and pricing behavior is related to an estimation method (several estimation methods) for public works bid in Japan. The two types of standard estimation methods produce different results that number of bidders (decide on bid-no bid strategy) and distribution of bid price (decide on mark-up strategy).The comparison on the distribution of bid prices showed that the percentage of the bid concentrated on the criteria for low-price bidding investigations have had a tendency to get higher in the large-sized public works by the unit price-type estimation method, comparing with the accumulated estimation method. On one hand, the number of bidders who bids for public works estimated unit-price tends to increase significantly Public works estimated unit-price is likely to have been one of the factors for the construction companies to decide if they participate in the biddings.

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 A nationwide micro-econometric model was established to estimate changes in the national gross product based on road-related investment amounts. And by considering the supply-demand balance during inflationary and deflationary times and the price adjustment mechanism, this model was then used to examine issues with the current micro-econometric model in light of the present economic circumstances. The results showed that during deflationary times issuing government bonds is less likely to have a crowding-out effect and public investments tend to be more effective than during inflationary times.

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 The purpose of this study is to clarify an impact of increase or decrease in population on demand for concrete in terms of consumption of cement in each prefecture in Japan during recent ten years. The amount of consumption of cement was employed as the index for the demand for construction. The increasing rate of concrete was employed as the index for the demand for construction this study, in which the ratio of the consumption of cement in a year to the accumulation up to the previous year. A hypothesis was set up in which the increasing rate of concrete is equal to the sum of the increasing rate of concrete per person and the increasing rate of population on condition that the amount of concrete structures has become enough. The error of the real increasing rate of concrete in each prefecture to the theoretical value was obtained for each year in 1980 to 2009 and each prefecture. The average error was almost 10 to 30% of the theoretical value and around 10% in 1990 to 2004. That can lead to that the population increasing rate should have been becoming a main factor for a regional difference in the demand for construction until 2004.

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 When constructing and renovating parks in Shinagawa city, we collect various needs from local citizens by briefing, workshop and public comment. However, only adult people usually come to workshop. And there are few expression by children who are main users of parks.
 Then we made plan of a new park with children who play major roles in their future as part of town development. This plan is shown in Shinagawa city basics design which instituted in April 2008. And during construction of it we held observation tour with children to get more familiar to their parks.
 After finishing construction, we are going to maintain together with them by planting flowers etc.
 In this way, we cultivate mind that adults and children conduct town development together by system in which children can continuously take part in each step of making parks.

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 By the enactment of the Bill for Ensuring the Quality of Public Works in 2005, which requires due consideration for the use of technical proposals, or iginality, and ingenuity of the private companies, as well as allows to cap estimates based on the results of evaluations of proposals involving advanced technologies, it becomes easier to request the technical proposals including the design of the structure.
 With this institutional arrangement, the Ministry of Land, Infrastructure, Transport and the Tourism (MLIT) tries the design-build method etc., in the aim of further utilizing the technical proposals of private companies. Although the design-build method allows a wider range of flexibility in proposals, there is a certain risk associated with this method, as it requires the tender price to be decided when the site condition is unclear. The risk was taken by the contractors when the design-build method was used on a trial basis, for the purpose of ensuring fair competitiveness. However, it was decided that the client shares the risk to some extent, after it was found that such risk assignment was not appropriate in some cases.
 In view of this background, this study examines the actual risk associated with the examples of public works projects, in the aim of providing basic information used in future discussions, as to how fair competitiveness shall be ensured, while the client shares some risk.

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