Survey Of Accidents Research Articles

Orhtophoto Accuracy Assessment of Ultra-light Fixed Wing UAV Photogrammetry Techniques

본 연구는 최근 국내외에서 문화재 보존, 사고현황조사, 군 정찰업무, 재난관리 등 다양한 분야에서 활용되고 있는 초경량 고정익무인항공기 사진측량의 성능평가를 다루고자 한다. 항공삼각측량 결과, 위치(X, Y)에서 RMSE 값은 약 10 cm로 나타났으며, UAV 사진측량의 정사영상에 대한 시각판독법(on-screen digitizing) 기법과 지상측량에 의한 필계점 좌표 차의 RMSE 는 X 방향 약 0.174~0.205 m, Y방향 약 0.294~0.298 m의 편위형 오차가 도출되었다. 그리고 실험대상지역의 임의의 1 필지를 대상으로 지적 공부대장면적과 UAV 사진측량의 정사영상으로 취득한 필지 면적을 비교한 결과 차이는 0.118 <TEX>$m^2$</TEX>이다. 본 연구는 초경량 고정익무인항공기 사진측량의 정사영상 정확도 평가에 대한 하나의 연구 사례를 제시하였으며, 향후 항공삼각측량(AT), 직접 기하보정(direct-georeferencing), 비행계획, 그리고 실용적 응용분야 개발 등에 대한 연구가 지속되어야 할 것으로 판단된다. The main purpose of this study is to carry out the performance evaluation of Ultra-light Fixed Wing UAV(Unmanned Aerial Vehicle) photogrammetry which is being, currently, applied for various fields such as cultural assets, accident survey, military reconnaissance work, and disaster management at home and abroad. Firstly, RMSE estimation of Aerial Triangulation (AT) are within approximately 0.10 cm in position (X, Y). And through the comparison of parcel's boundary points coordinates by terrestrial surveying and by UAV photogrammetry, the analysis shows that RMSE are shifted approximately 0.174~0.205 m in X-direction, 0.294~0.298 m in Y-direction respectively. Lastly, parcel's area by orthophoto of UAV photogrammetry and by that of cadastre register has been shown the difference by 0.118 m2. The results presented in this study is just one case study of orthophoto accuracy assessment of Ultra-light fixed wing UAV photogrammetry, hereafter various researches such as AT, direct-georeferencing, flight planning, practical applications, etc. should be necessary continuously.

Potential Benefits of Underride Guards in Large Truck Side Crashes

Objective: To evaluate the maximum potential for side underride guards (SUGs) to reduce passenger vehicle occupant fatalities and injuries in crashes with large trucks in the United States. Methods: Examination of the Large Truck Crash Causation Study (LTCCS) identified 206 crash events involving a passenger vehicle impact with the side of a large truck. Each case was evaluated to determine whether the most severe injury sustained by a passenger vehicle occupant was a result of the impact with the side of the truck and whether an SUG could have reduced the injury severity. Data from the 2006–2008 Fatality Analysis Reporting System (FARS) and Trucks Involved in Fatal Accidents (TIFA) survey were used to compare the types of trucks involved in all fatal side impacts with passenger vehicles with the truck types in the LTCCS cases that were studied. FARS and TIFA data also were used to estimate the total annual number of passenger vehicle occupants killed in truck side impacts. Results: In 143 of the 206 cases, the truck side impact produced the most severe injury sustained by a passenger vehicle occupant. In the other cases, no passenger vehicle occupant was injured or the most severe injury was due to an event preceding or following the truck side impact. Forty-nine of these occupants sustained injuries coded as level 3 or higher on the abbreviated injury scale (AIS) or were killed. SUGs could have reduced injury severity in 76 of the 143 cases, including 38 of the 49 cases with an AIS ≥ 3 coded injury or fatality. Semi-trailers were the most common type of impacted truck unit, both overall and when considering only cases where an SUG could have mitigated injury severity. Crashes where the front of the passenger vehicle struck the side of the semi-trailer perpendicularly or obliquely from the oncoming direction were less common overall than side-to-side and oblique/same direction crashes but more often produced an AIS ≥ 3 injury or fatality. The distribution of truck types in the LTCCS sample was similar to that in the FARS and TIFA data. Overall, around 1600 passenger vehicle occupants were killed in 2-vehicle truck side impact crashes during 2006–2008, or 22 percent of all passenger vehicle occupants who died in 2-vehicle crashes with large trucks. Conclusions: Structural incompatibility was a common factor in LTCCS crashes between passenger vehicles and the sides of large trucks. SUGs could have reduced injury risk in around three fourths of the crashes that produced an AIS ≥ 3 injury or fatality. Most of these crashes involved semi-trailers. However, the necessary strength and location of these SUGs present technical challenges that need to be addressed.

Thoracic Injury Assessment for Improved Vehicle Safety

Thoracic injuries are one of the dominant causes of fatalities and severe injuries in car crashes today. The tools available today for studying these injuries are not up to par with the latest implementation of restraint systems and airbags. THORAX is a collaborative medium scale project under the Seventh Framework, Theme 7 Transport which focusses on reduction and prevention of thoracic injuries through:•Understanding the thoracic injury mechanisms•Implementation of this understanding in numerical computer models and•Implementation of an updated thorax design in a crash test dummyThe models and dummy will enable the design and evaluation of advanced restraint systems for a wide variety (gender, age and size) of car occupants. The THORAX project started in February 2009. This paper presents results achieved during the first two years of the project including outcomes of accident surveys, human body modelling activities and hardware dummy developments.

Design, Manufacture and Maintenance of Pressure Equipment Based on Accidents Survey

Most of the important units of pressure equipment have been manufactured successfully in China related to the national key construction projects,such as 10 million tons/year oil refinery,million tons/year ethylene,large coal chemical,etc.However,some of them failed to operate shortly after their putting into service.Some suffered severe damage even during the previous period of manufacture and installation.In this paper,cases of accident survey and failure analysis are given for some typical pressure vessels.It is found that many accidents are related to insufficient consideration of the design and manufacture of the equipment.These accidents occur fundamentally because of the Chinese design standards codes for pressure equipment without risk or life concepts and the support from a database for potential risk existing in their dynamic service.Most designers and manufacturers are unable to make correct design,materials selection and manufacturing process all due to a lack of engineering experience.In order to avoid the repetition of the accidents and improve the safety,reliability and economy of pressure equipment,a platform is suggested for design,manufacture and maintenance of pressure equipment in China based on accidents survey.In other words,some effective precautionary measures are taken at the design and manufacture stage,and the design methodology has to be based on service life requirement and desirable risk level.At the service stage some reasonable inspection/monitoring approaches should be utilized to control risks and ensure the equipment operating safely until its desired lifespan.Finally,the basic scheme and some key technologies are briefly given for the platform construction.The concept of risk and life based design,manufacture and maintenance proposed herein has important significance for improving and perfecting the codes and standards for design,manufacture and maintenance of Chinese pressure-bearing equipment,enhancing the life and reliability of Chinese pressure-bearing equipment and promoting the development of in-service maintenance technology that combines safety and economy.

Development of Coordinate-machine of the Scene of Road Traffic Accident based on Binocular Stereo Omni-Directional Vision Sensors

On the basis of analyzing flaws of the traditional means of traffic accident scene survey and inadequate of the existing photogrammetry technique, this paper presents a panoramic stereo photogrammetry technology applying to traffic accident survey. By employing the result of photogrammetry, the drawing module can automatically draw traffic accident scene diagrams for the accident analysis and reconstruction, so as to quickly achieve the purpose of measurement and drawing.Experiments show that the presented accident scene coordinate-machine can measure the distance and the azimuth of all the relevant objects on the accidental scene, and enjoys the advantages of high precision in measurement, convenience in operation and carry, no necessity in calibration,etc. So it can meet the traffic police's needs of the measurement and drawing of the traffic accident scene.

고령화 사회의 근골격계질환관련 대응전략

The purpose of this study was to show the occurrences of musculoskeletal disease in aging society and basic information on developments of a systematic prevention program and proposed management measures needed to prevent the disease. The Korea Occupational Safety & Health Agency has analyzed cases of industrial accidents that cause musculoskeletal disease, from 1998 to 2007. They found 30,439 people suffering from the disease during those ten years. This information is from the Ministry of Labor's industrial accident analysis and the industrial accident survey from the Korea Occupational Safety & Health Agency. The data was analyzed by age and industrial classification. In Korea, according to the studies on aging society, the occurrence of musculoskeletal disease in elderly employee's have increased, so prevention programs are needed. Psychological, mental and cognitive programs are needed, as well as other prevention programs to ensure health in old age. In this study, we were able to see the state of musculoskeletal disease in aging society and the countermeasures to prevent the disease, such as a universal design, guarantees, and recuperation services. Later, we found that studying the various elderly patients would be of great help to us.

Failure analysis of the brittle fracture of a thick-walled 20 steel pipe in an ammonia synthesis unit

In this paper, the analysis of a brittle fracture explosion accident of a thick-walled 20 steel pipe, which connects the outlet of an ammonia separator and the inlet of a cold exchanger in an ammonia synthesis unit of a chemical fertilizer plant, is presented in detail. The causes and mechanism of the material degradation are investigated by analyzing chemical compositions (especially the elements of nitrogen, hydrogen), testing mechanical properties, observing microstructures and defects, and strain aging sensitivity, and analyzing annealing behavior of the pipe. Furthermore, the mechanism of crack initiation and propagation are analyzed carefully through macro- and micro-crack observations by means of Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The research results not only support the conclusions given by the accident survey group, but also clarify the uncertainty in the report of the survey at that time. The further research makes it clear that the decrease of material toughness due to strain aging embrittlement (SAB), and the crack initiation and propagation is caused by SAB and its lowering effect on the threshold value of hydrogen-induced cracking (HIC). The research work described in the paper has a significant meaning to recognize or eliminate SAB occurred in quite ductile plain carbon steels very commonly used in industry, such as 20 steel in China.

Laser Scanner-based End-effector Tracking and Joint Variable Extraction for Heavy Machinery

A survey of mining accidents has revealed that over 30% of all truck loading accidents can be addressed by providing dipper positioning feedback to the shovel operator. In this paper, a novel approach is presented for estimating a mining shovel’s dipper pose to obtain its arm geometry in real-time utilizing a two-dimensional laser scanner. The low spatial resolution of laser scanners and the need for accurate initialization challenge the reliability and accuracy of most laser-scanner-based object tracking methods. This work addresses these issues by using the shovel dipper’s kinematics model and position history, in conjunction with the dipper geometrical model, to track the dipper in space. The proposed method uses a bootstrap particle filter with a distance transformation in order to perform a global search in the workspace. The particle filter’s result is then used as the initial pose for an Iterative Closest Point algorithm that increases the accuracy of the pose estimate. The proposed method can be applied to other laser scanner-based object tracking applications in outdoor environments. Experiments performed on a mining shovel demonstrate the reliability, accuracy, and computational efficiency of the proposed approach. Moreover, using a single proximal sensor can simplify mounting, reduce maintenance costs and machine down time, and enhance tracking reliability.

Development of a Kilometer-Based Rewards System to Encourage Safer Driving Practices

Interest is growing in the use of kilometer-based financial mechanisms to encourage safer driving practices and reduce accident claims. The rationale behind such an approach is that, in addition to driver characteristics such as age and gender, crash risk is intrinsically a function of both the kilometers driven and the circumstances under which those kilometers are driven (e.g., time of day, day of week, road type, speed). Using recent accident data and travel survey data collected in the Sydney, Australia, greater metropolitan area, options were explored to design a kilometer-based reward scheme that incentivized drivers to reduce their kilometers traveled, nighttime driving, and speeding. Results show that young drivers (17 to 30 years old) would be hardest hit by the proposed scheme, and middle-aged drivers (31 to 65) would fare best. The impacts of the rewards system were assessed hypothetically by using evidence from 125 motorists who completed 5 weeks of driving in which their kilometers traveled, nighttime driving, and speeds were monitored with the latest Global Positioning System technology. Various charging scenarios and hypothesized behavioral changes were implemented to assess both their incentive for change and the overall financial impact of the project. These results were used in conjunction with the theoretical and empirical justification outlined in this paper to set the final charging regime rates on the basis of the overall study budget.

A joint modeling of injury severity and collision type for examining influential factors of traffic accidents occurring at intersections of national highways in Japan

This paper aim to provide additional insights of using a bivariate ordered probit model to simultaneously examine influential factors that affect injury severity (IS) and collision type (CT) of traffic accidents occurring on intersections of national highways in Japan. The effectiveness of the bivariate model is re-confirmed using large-scaled traffic accident data. The corrections between error terms of IS and CT are statistically significant, implying that there are some unobserved factors that simultaneously affect IS and CT, but are not well captured in traditional accident surveys. Six types of collisions are dealt with and their influential factors are examined with respect to both primary and secondary parties. A complicated structure of influential factors is clarified, and it is expected that such complexity cannot be properly captured based on the widely applied cross-aggregation method in practice.

Occupational injuries and fatalities in copper mining in Zambia

The metal mining industry employs approximately 15% of formally employed workers in Zambia, but there is little information about the magnitude of occupational injuries among the miners. To determine the frequency rates of occupational injuries and fatalities among copper miners in Zambia. A retrospective study of occupational injuries and fatalities at one of the largest copper mining companies in Zambia was undertaken for the period January 2005 to May 2007. Information on injuries and fatalities was obtained from the electronic accident survey database of the company. Analysis was restricted to fatalities and those injuries that had prompted medical attention and at least 1 day of absence from work. Annual injury and fatality frequency rates (injuries per 1000 employee years and fatalities per 100 000 employee years, respectively) were calculated. In the selected period, 165 injuries and 20 fatalities were recorded. The underground department had the highest frequency rates of fatalities (111/100 000 employee years) and injuries (5.5/1000 employee years). The most common cause of fatal injuries was fall of rock in the underground mines. The most frequent mechanism of injury was handling of tools and materials, and the most commonly injured body parts were the hands and fingers. The fatality rate is high compared to reported values from the metalliferous mining industry in developed countries, strongly suggesting that measures should be taken to reduce risks, particularly at underground sites.

Survey of domestic accidents in the elderly in the Province of Genoa (northern Italy).

Accidents in the home are a major public health issue in most industrialised countries, as they are a frequent cause of injury and death. Moreover, since a considerable portion of such accidents involve elderly people, it is important to assess their social impact in this population. In Italy, the available data indicate that well over 3 million people per year suffer accidents in the home, and that this number is rising. The aim of the present study was to evaluate the number, characteristics and causes of domestic accidents among the elderly. The study population was made up of subjects of both sexes aged between 65 and 92 years admitted to first aid units and emergency departments of hospitals in Genoa. The investigation was conducted by means of an ad hoc questionnaire designed to record the circumstances of the accident, the functional capacity of the subject involved, any risky behaviour enacted and the safety profile of the subject's home. The study enrolled 111 voluntary participants: 62 women and 49 men. At the time of the accident, subjects were engaged in the following activities: housework (36.9%) "rest" (14.5%), ablutions (10%), gardening (9%), leisure activities (8.1%), eating and drinking (2.7%). The most common injuries were bruises (39.6%), followed by fractures (23.4%) and cuts (23.4%); the frequency of other, some time more severe injures (burns, poisoning, asphyxia, crush injuries, etc.) was,fortunately, very low. Anyway, taking into account their consequences, their surveillance and prevention is very important. Most subjects were deemed to be in good health and, in 76% of cases, the safety profile of their houses proved to be satisfactory. The data collected during this survey are in line with those yielded by national and international studies. They show that the elderly are very vulnerable to domestic accidents and that, even in the event of only slight injury, the management of elderly victims requires a strong organisational commitment on the part of relatives and considerable financial resources for healthcare services. Falling proved to be the main cause of injury. Clearly, efforts to reduce the cost of accidents in the home should aim to implement preventive intervention among elderly people, since the elderly population is destined to grow as a result of increasing life expectancy. In particular, preventive action should focus on reducing the incidence of falls by eliminating risk-related structural features in domestic settings as far as possible and by raising public awareness of the problem through health education campaigns.

Incident and Accident Survey of Geriatric Dental Practice

Incident and Accident Survey of Geriatric Dental Practice

Operational and accident survey of Russian nuclear submarines for risk assessments using statistical models for reliability growth

In this study, 165 safety related events involving Russian nuclear submarines from 1959 to 2007 are surveyed with respect to vessel generation, reactor type, various types of initiating event (loss-of-coolant accident (LOCA), transients, common cause initiators (CCI)), safety significance and the release of radioactivity. The survey of vessel operations shows that the accumulated number of vessel operating years (VOY)/reactor operating years (ROY) from 1959 to 2007 is 4991/9335. With respect to the survey of safety related events, out of the 165 events registered, there have been identified 17 accidents, 133 incidents and 15 deviations. As to event characteristics, 14 LOCA and 7 criticality events have been identified. The accident rates for each of the vessel generations exhibit the usual characteristics of a technological system under development, gradually going from a high accident rate to a stable lower level – however, with clear differences between reactor technologies (PWR versus LMC) and vessel generations. The mean-time between failures (MTBF) for various types of safety related events for the Russian nuclear submarines has been calculated for various events using the non-homogeneous Poisson process (NHPP) power-law model. When applied to the complete set of events, this model fails due to a cluster of safety related events that occurred between 1984 and 1987. With respect to releases of radioactivity, the MTBF has been calculated to 893 ± 138 VOY. All safety related events identified as part of this study are given in Appendix 1.

A community based survey of cognitive functioning, highway‐code performance and traffic accidents in a cohort of older drivers

The DVLA allows driving in early dementia contingent on regular medical assessment. GPs and psychiatrists require validated and accessible assessments. Some studies have suggested that cognitive testing has utility in the assessment of driving capacity in elderly drivers. One study raises the possibility of using a highway-code questionnaire as an adjunct to these tests. Two hundred drivers over the age of 65 were randomly selected from two GP surgeries. Baseline assessment comprised completion of a Highway Code questionnaire (DPHC-98), the Mini Mental State Examination (MMSE) and an abbreviated version of the Alzheimer's Disease Assessment Scale Cognitive Subsection (EURO-ADAS). A history of road traffic accidents (RTAs) over the preceding 5 years was obtained. At 12-month follow-up interview driving status of the subject and occurrence of RTAs were recorded. Predictive power of DPHC-98 and cognitive testing with regards RTAs were examined through logistic regression analysis. Performance on the Highway Code questionnaire was identified as the only significant regression factor in the prediction of prospective RTAs. However, none of the logistic regression models were able to identify any drivers involved in RTAs either retrospectively or prospectively. Cognitive tests are not linked with risk of driving accidents in older adults in any useful way.

Chain Breakers—A Survey of Fatal Ship Accidents With the Event-Chain Method

The ship research project DESSO (Design for Survival Onboard) aims at improving the safety of RO/RO (roll-on/roll-off) ferries. The project was organized in the autumn of 2003 in order to use the research and development resources existing in Sweden, combined with international expertise, for a radical RO/RO concept with a focus on safety. One part in the early stages of this project was to identify chain breakers from previous accidents, that is, something that would have prevented, stopped, or reduced the conse-quences of the incident event, in order to obtain a realistic basis of "working on the right problem." A systematic and in-depth analysis of a few selected significant and well-documented disasters was made using the event-chain method. The identified chain breakers were further categorized and analyzed to find ideas and concepts that would prevent these events from occurring. These efforts were further developed into a method where the graphics of event chains with chain breakers are used in workshops with experts in two stages. In general, it was found that "Management" in most cases was the initial cause of the events. Often, "Management" was also the reason for the continuing or worsening of the events. As such, education/training and stricter routines were found to be the most effective methods for reducing accidents and are at the same time an inexpensive measure to take. This, together with online stability calculations and decision-support systems, would have prevented most of the accidents analyzed in this work.

A NURSE PRACTITIONER-LED FARMERS‘ HEALTH SERVICE: SETTING UP AND EVALUATING A UK PROJECT

ABSTRACT: The farming community in the UK have significant unmet health-care needs that have traditionally remained invisible. The project that is the subject of this paper is an attempt to improve access to health care for farmers and make their needs visible. It is based in an upland area of England and involves two nurse practitioners (NPs) and two support workers who provide health care for the farming community. The main targets of the project are farm accidents, mental health and occupational diseases. The NPs visit farms, on request, for consultations and also attend auction marts, agricultural shows and other farmers' meetings. Evaluation is by a telephone follow-up interview with a sample of clients seen by the N P, who will be compared with a group from a similar area who do not receive the service. A farm accident survey is underway, case notes are being audited and the NPs are keeping a reflective diary as further sources of data.

The role of surgical audit in improving patient management; nasal haemorrhage: an audit study

BackgroundNasal bleeding remains one of the most common Head & Neck Surgical (Ear Nose and Throat [ENT]/Oral & Maxillofacial Surgery [OMFS]) emergencies resulting in hospital admission. In the majority of cases, no other intervention is required other than nasal packing, and it was felt many cases could ideally be managed at home, without further medical interference. A limited but national telephone survey of accident and emergency departments revealed that early discharge practice was identified in some rural areas and urban departments (where adverse socio-demographic factors resulted in poor patient compliance to admission or follow up), with little adverse patient sequelae. A simple nasal packing protocol was also identified.The aim of this audit was to determine if routine nasal haemorrhage (epistaxis) can be managed at home with simple nasal packing; a retrospective and prospective audit.Ethical committee approval was obtained. Similar practice was identified in other UK accident and emergency centres. Literature was reviewed and best practice identified. Regional consultation and feedback with regard to prospective changes and local applicability of areas of improved practice mutually agreed upon with involved providers of care.MethodsRetrospective: The Epistaxis admissions for the previous four years during the same seven months (September to March).Prospective: 60consecutive patients referred with a diagnosis of Nasal bleeding over a seven month time course (September to March). All patients were over 16, not pregnant and gave fully informed counselled consent.New Guidelines for the management of nosebleeds, nasal packing protocols (with Netcel®) and discharge policy were developed at the Hospital. Training of accident and emergency and emergency ENT staff was provided together with access to adequate examination and treatment resources. Detailed patient information leaflets were piloted and developed for use.ResultsPreviously all patients requiring nasal packing were admitted. The type of nasal packing included Gauge impregnated Bismuth Iodoform Paraffin Paste, Nasal Tampon, and Vaseline gauge. Over the previous four year period (September to March) a mean of 28 patients were admitted per month, with a mean duration of in patient stay of 2.67 days.In the prospective audit the total number of admissions was significantly reduced, by over 70%, (χ2 = 25.05, df = 6, P < 0.0001), despite no significant change in the number of monthly epistaxis referrals (χ2 = 4.99, df = 6, P < 0.0001). There was also a significant increase in the mean age of admitted patients with epistaxis (χ2 = 22.71, df = 5, P < 0.0001), the admitted patients had a mean length of stay of 2.53 days. This policy results is an estimated saved 201.39 bed days per annum resulting in an estimated annual speciality saving of over £50,000, allowing resource re-allocation to other areas of need. Furthermore, bed usage could be optimised for other emergency or elective work.ConclusionExclusion criteria have now been expanded to exclude traumatic nasal haemorrhage. New adjunctive therapies now include direct endoscopic bipolar diathermy of bleeding points, and the judicious use of topical pro-coagulant agents applied via the nasal tampon. Expansion of the audit protocols for use in general practice.This original audit informed clinical practice and had potential benefits for patients, clinicians, and provision of service. Systematic replication of this project, possibly on a regional and general practice basis, could result in further financial savings, which would allow development of improved patient services and delivery of care.

Baumunfälle im Straßenverkehr - Unfallmechanismus und Verletzungsmuster

In Germany, the county of Mecklenburg-Vorpommern has got the highest frequency of traffic accidents. 42 % of all deadly injured car accident victims in Mecklenburg-Vorpommern sustained a tree collision. Aim of this study was to analyze tree collisions regarding typical pattern and severity of injury. During an on-going prospective, non-interventional accident survey within a defined area of the county of Mecklenburg-Vorpommern tree collisions with minimum one victim sustaining a Maximum Abbreviated Injury Scale of 1-6 injury were analyzed. In between January 2001 and June 2004 287 accidents were documented. 19 % (54) were tree collisions. 81 % of drivers were male. 36 of 54 tree collisions (67 %) occurred on straight roadways. The mean ISS was 31.3 (SD +/- 29.8), 30 % (23) of the passengers died. 70 of 78 individuals sustained more than one injury. With that, the combination of head- and chest trauma was most frequent and associated with the highest injury severity. Especially tree collisions lead to severe trauma. Interestingly, most accidents did occur on straight roadways.

Risk factors for traffic accidents in patients with obstructive sleep apnea syndrome

A survey of traffic accidents incurred by 440 patients with obstructive sleep apnea syndrome determined the prevalence of traffic accidents in this group. The study also determined the independent risk factors for accidents in these patients with obstructive sleep apnea syndrome before and after the initiation of continuous positive airway pressure therapy. Before continuous positive airway pressure therapy, 43.4% of the patients had had traffic accidents. The independent risk factors for accidents were higher body mass index, excessive daytime sleepiness, frequent driving and long-distance driving. Accidents occurred most frequently under circumstances of driving at a low speed, as in a traffic jam. The accident rate after continuous positive airway pressure therapy was 5.7%, and significant risk factors were higher age, presence of residual excessive daytime sleepiness, and higher body mass index. We conclude that it would be beneficial to establish a system for detecting unrecognized obstructive sleep apnea syndrome with a view to treatment, in order to reduce the prevalence of traffic accidents. Additionally, it is necessary to check for residual sleepiness after treatment with continuous positive airway pressure, and advice to lose weight is essential.