: In the construction industry, recently many labor accidents occur due to unsafe behavior or human error of workers rather than trouble with machinery or equipment. Recent research has some advances in revealing the factors that cause unsafe behavior at work sites and the effective prevention measures. However, it is also clarified that workers of different ages or positions have different attitudes or perceptions for safety or accident prevention. In order to perform safety measures smoothly at work sites, it is required for all the workers at the site to understand the same safety policy and plan of the site or company.
    In this research, the difference of attitudes and perceptions of workers by position on safety and accident prevention was examined and the effective safety measures were discussed.
    The sets of questionnaires were distributed to the supervisors of work sites and on-site staff of general contractors, foremen and workers of affiliated companies at 21 work sites of 7 general contractors and 558 copies (97.9%) were collected.
    As a result, the difference in response patterns by 4 positions was observed in many question items. Especially large and significant differences were observed between the supervisors of the work sites and workers of affiliated companies.
    Supervisors of work site paid much attention to various matters and thought these matters would cause accidents. And for accident prevention, they thought highly of the safety measures made by general contractor for their own responsibilities and safety attitudes of staffs of both general contractor and affiliated company.
    On the other hand, workers thought little of management issues on safety or attitudes of staff except the supervisors of work sites. Workers appealed against the necessity for the practical safety measures during work, and safety patrols and regulations.
    It is required to find and cancel the gaps among staff of the 4 different positions, the supervisors, on-site personnel, foremen and workers, on safety and accident prevention by active and smooth communication between different positions in the meetings or at work, in order to enforce safety measures effectively and to promote a good safety climate.

Keywords;Construction work, Unsafe behavior, Construction work site, Safety measure, Communication, Management

: In cases of communication of inappropriate information between the original contractor and the subcontractors at construction sites, labor accidents might occur. Therefore, the procedure of communication at construction sites was investigated. Construction site had 5 types of communication. Those were morning assemblies, KY activities, task coordination meetings, instructions for new recruits and conferences on safety & health. These types of communication were classified into two types from the point of informational channel. One type was "Vertical Direction Channel on top-down of Construction", which was a one-way formal communication from the top director of the original contractor to workers of the subcontractors. The other type was "Horizontal Direction Channel within the top-down of Construction", which was mutual communication by workers of the subcontractors. It was possible for "Top-down Channel" to inform many workers. "Horizontal Direction Channel" was capable of asking questions or consultation with workers. The procedures of communication on morning assemblies and instructions for new recruits were the type of "Top-down Channel". KY activities, task coordination meetings and conferences on safety & health were combinations of two types, namely, "Top-down Channel" and "Horizontal Direction Channel".
    The instructions for new recruits were the type of "Top-down Channel". These instructions were not able to ask questions or consultations with new recruits. Therefore it was necessary to use questionnaire to obtain the data about safety instructions. As a result of this investigation, because of not being able to ask questions to workers, it was difficult for new recruits to predict risky behavior in the initial stages at construction sites. This is the main reason for new recruits to sustain injuries. From this investigation, the effective instruction method of prevention labor accidents for new recruits was considered. The new instruction method has two points. One point was to train by classification of new recruits as a small group. The other point was to train at thework site. By the adoption of this new instruction method, it would be easy for new recruits to prevent laboraccidents.

Keywords; Construction site, One-way communication, Mutual communication, Safety information

: A large excavator simulator for research was developed, and the research on the operator's actions was done. On the basis of these experiences, a small PC based simulator was developed for the safety training. This simulator has a front screen with 6 planes, 8 projectors, a driver's seat on a motion base, and PCs that generate CG images and control the system. A set of 4 projectors is used to project 4 images to 6 planes for one-eye, and 2 sets of projectors are used for stereoscopic viewing. The aim of the simulator is to give simulated experiences of excavator accidents. A turnover accident in driving on a slope, in loading to the truck and in running over uneven surfaces can be experienced.
   The performance of the small simulator was evaluated in comparison with the large simulator. Occupied area of the system is considerably reduced. The brightness of screen images is improved and the images can be seen with illumination, which means this system can be used in an ordinary meeting room. There is some defect in uniformity of the brightness of screen images because of the complexity of the projection, that is, projections with 8 projectors to 6 planes. The ratio of the area of the projection image in the visual field is nearly same as that of the large simulator. The degree of freedom of the motion base is reduced from 6 to 2, but the expressive effect is sufficient forthis content.
   The performance of the new characteristics of the small simulator was also evaluated. The simulator has flexibility in the projection system, that is, capability of reduction of projectors. A projection system of 2 images is possible, but the expressive effect will be reduced. The system is portable, because it can be disassembled, but it is difficult.

Keywords; Excavator, Accidents, Simulator, Simulated Experience

: Recently, the imitative experience methods have been adopted in safety education for workers in Japan. Some employ a simulator which is supported by the computational technologies for making virtual danger. Others show the imitative disasters (ex. electrification, falling object, gas explosion, pinched hand, getting caught in rollers, etc.) to workers by using working models or specific devices. Also, there is a way of making workers experience actual (but little) danger by using real machinery under the controlled condition.
    These methods are applied to the safety education and training with the intention of the improvement in risk sensitivity and risk taking behavior of workers. It is said that the workers who have never suffered a real accident would only know the risk of their work just as knowledge, and they tend to ignore the safety performance of their work. The applications of imitative- or virtual-risk experiences emphasize the risk sensitivity of workers. Finally, the risk-experienced workers get the practical knowledge for their work. These imitative experiences are actually effective and used widely, they would be useful for the prevention of the labor accidents in Japan.
    However, these new educational methods have not been established yet. Because, the details of these methods have never been examined and some serious problems remain unsettled. Making too much of unusual and shocking experiences would give a transitory surprise and superficial fright to workers. A mere imitative experience without the consideration about the procedures of accident prevention would never bring substantial improvement to safety attitudes of workers. The most serious issue is "Risk compensation" which tends to be caused by the practical safety training, and it might not only cancel the effects of a safety education and training, but also promote the risk taking behavior of worker. Most instructors who engage the education and training of industrial safety do not have knowledge concerning this serious issue, and have not developed management skills.
    Based on these issues, the importance of making associations of events in real situations with ones in the imitative experiences, how evaluate risk in real situations, and the consequence of the image-training about procedures to prevent accidents in one's mind are discussed in this study. As a procedure to develop safety skills of workers in the long-range, the concept of "Imagination Spiral" is suggested.

Keywords; safety education, risk perception, risk taking, simulator