• 한국도로학회논문집
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• 제18권4호
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• pp.77-82
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• 2016

PURPOSES : This paper proposes a reliability index for the safety evaluation of freeway sections. It establishes a reliability index as a safety surrogate on freeways considering speeds and speed dispersions. METHODS : We collated values of design elements including radii, curve lengths, vertical slopes (absolute values), superelevations, and vertical slopes from seven freeway sections in Korea. We also collected data about driving speeds, traffic accidents, and their deviations. We established a reliability index using these variables. RESULTS : The average radii, curve lengths, and superelevations are highly correlated with the incidence of traffic accidents. Deviations in radius and curve lengths show an especially high correlation. The reliability index, derived from speed and speed dispersions of the seven freeway sections, also correlated highly with accidents with a correlation index of 0.63. CONCLUSIONS : Since the reliability index obtained from speed and speed dispersions are highly correlated with traffic accidents, we conclude that a reliability index can be a safety surrogate on freeways considering speeds and speed dispersions together in terms of design and operational levels.

• 한국ITS학회 논문지
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• 제23권2호
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• pp.32-49
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• 2024

본 논문에서는 도로교통 여건과 제한속도 변화가 교통소통과 안전에 미치는 영향을 분석하였다. 교통소통지표로 통행속도와 순행속도, 「순행속도-통행속도」, 편차, 대편차비율, 상충횟수 등을 안전지표로 설정하고 도로교통 여건과 제한속도 변화가 이들에 미치는 영향을 분석하였다. 분석 결과에 의하면 제한속도는 소통지표에는 크게 영향을 주지만 안전지표에는 크게 영향을 주지 않는 것으로 분석되었다. 통계적 유의성 검정 결과 제한속도가 증가함에 따라 소통지표는 증가한다는 것이 유의하다고 입증되었다. 그러나 안전지표들은 증가하는 경우가 많지만 통계적으로는 유의성이 입증되지 않았다. 그러므로 다양한 도로여건과 교통량 변화에 따른 교통흐름 상태를 현실적으로 고려해서 제한속도가 설정되고 운영된다면 운전자들이 주행하는 속도에 부합되고 교통소통과 안전이 향상된다고 할 수 있다. 따라서 본 논문에서 제시한 교통소통지표와 안전지표들을 고려하여 제한속도를 산정하고 교통량 변화에 따라 제한속도를 운영할 경우 도로상의 교통 흐름을 안정화시키는 데 기여할 것으로 기대된다.

• 한국안전학회지
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• 제25권2호
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• pp.78-83
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• 2010

An installation of automated speed enforcement system(ASES) was known for traffic safety and accident preventive effects that traffic characteristics transmute by speed distribution stabilizing. This study is verified the variations of average speed, 85% speed, speed distribution and dispersion as traffic characteristics depend on enforcement system influences in the road. We tested selected 5 areas. By and large, it has a little differences depend on road geometric structure and traffic environment but that is not too much. After all, after automated speed enforcement system installed in all of test areas, average speed, 85% accumulated speed, speed distribution and dispersion characteristics were declined and equalized. The speed dispersion was smaller than before installed the ASES. The speed dispersion value of each case that is the limited speed has been 70Km/h, 80Km/h at flat and straight, 80Km/h at downhill and straight or downhill and left-curved area was 77.3%, 65.2%, 68.7% and 54.1%. Each of the data was declined. We could analyze that average speed distributed depletion factor was declined rapidly by 66.3% in test area.

• 한국안전학회지
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• 제31권5호
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• pp.158-170
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• 2016

It has been applied several ways in order to prevent traffic accidents and speed management on the road which is one of very important factors to prevent accidents. In this study, it is analyzed whether the facility such as the flashing and crosswalk, speed cameras and intermittent warning signs affect on a driving deceleration or not. It has been shown that the flashing and crosswalk and speed cameras except intermittent warning signs play a role of reducing the driving speed. The result showed that these traffic safety facilities help to improve the average speed as well as velocity distribution which was derived by the speed deviation even if there were the difference between facilities. Speed limit display does not affect the deceleration of the driver. Therefore, it was founded in this research that there were the driving speed reduction effect due to the facilities on the road. In order to control the driving speed on the road, it is necessary to install facilities with appropriate location and spacing on the road. In addition, place that turns out suppressed speeding through speed management also are required adequate facilities such as speed cameras.

• Wind and Structures
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• 제27권4호
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• pp.255-267
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• 2018

This paper investigated the wind-snow flow around the bogie region of a high-speed train under crosswinds using a coupled numerical method of the unsteady Realizable $k-{\varepsilon}$ turbulence model and discrete phase model (DPM). The flow features around the bogie region were discussed and the influence of bogie fairing height on the snow accumulation on the bogie was also analyzed. Here the high-speed train was running at a speed of 200 km/h in a natural environment with the crosswind speed of 15 m/s. The mesh resolution and methodology for CFD analysis were validated against wind tunnel experiments. The results show that large negative pressure occurs locally on the bottom of wheels, electric motors, gear covers, while the positive pressure occurs locally on those windward surfaces. The airflow travels through the complex bogie and flows towards the rear bogie plate, causing a backflow in the upper space of the bogie region. The snow particles mainly accumulate on the wheels, electric motors, windward sides of gear covers, side fairings and back plate of the bogie. Longer side fairings increase the snow accumulation on the bogie, especially on the back plate, side fairings and brake clamps. However, the fairing height shows little impact on snow accumulation on the upper region of the bogie. Compared to short side fairings, a full length side fairing model contributes to more than two times of snow accumulation on the brake clamps, and more than 20% on the whole bogie.

• International Journal of Internet, Broadcasting and Communication
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• 제6권2호
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• pp.20-24
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• 2014

These days the large-scale car accidents have often been occurred by overspeeding in disregard of sharp curve, foggy and freezing regions. This paper has proposed the algorithm to calculate the safety speed in real time that can protect the car accidents under these weather and road conditions using Fuzzy reasoning theory. Under raining and snowing, drivers have to slow down the traffic safety speed by 1/3 of the traffic safety speed indicated on the existing speed sign plate based on their decision. So it is difficult to calculate and then observe the safety speed. This paper has performed the simulation that provides the deivers with the optimal safety speed considering the road and weather conditions in real time to improve these problems. We have proved this method can improve more 25% than the existing one.

• 한국안전학회지
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• 제25권6호
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• pp.186-196
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• 2010

It has been well known that traffic accidents occur under combined functional contributions of drivers, vehicles and road facilities, and that evaluation of safety levels for a specific road section or point is generally much complicated. Additionally, most of traffic accidents occur randomly implicating it is necessary to be evaluated in terms of probability theory. Thus, the evaluation model which reflects various characteristics and probabilistic distributions of traffic accidents has been necessary. The present paper provides a reliability based model with variables of probabilistic operating speeds and design speeds together which have been individually explaining associated characteristics in traffic accidents. Consequently, the model made it possible for speed management and road improvement projects to be evaluated in a common index. Application studies were performed in three cases. Through the studies, couples of facts were identified that the model successfully considered the probabilistic operating speeds and design speeds together and that then, the model evaluated road safety alternatives relatively which are complicatedly characterized and differently located.

• 한국도로학회논문집
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• 제15권1호
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• pp.111-119
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• 2013

PURPOSES: Though the situation that the roundabouts are actively constructed, researches on the effect of the roundabouts focus mainly on the analysis of the expected effects of using only traffic simulation on the operation. Considering such problems, this study is conducted to analyze the effects of the various aspects based on field observation studies. METHODS: This study evaluated and analyzed the effects from the aspects of traffic operation, traffic safety, and traffic behavior by performing field observation studies with six roundabouts with/without signal controls on the pilot project areas for the roundabouts installed in 2010. RESULTS: Through the study results, it was found that the average travel time decreases by 14.7% and 2.4% on the signalized intersections and unsignalized intersections, respectively. The average travel speed increases by 9.7 and 5.8km/h on the roundabouts with/without signal lights. Regarding traffic safety, the speed deviation among individual vehicles decreases by approximately 18.4 to 32.7km/h, thus confirming the safety effects. As the decrease of the number of conflicts, it might be explained that car crashes and collision with pedestrians decreased by 62.2% and 66.7%. Also the result shows that the lowest point of speed in roundabouts appears near the yield line on the entry area on the roundabouts. When passing through the roundabouts, vehicles enter at a speed of 20-30km/h, which is the design speed of the circulatory lane and drive out the roundabout with a higher speed than the entry speed. CONCLUSIONS: When a roundabout is introduced at the intersections below certain traffic volume there are effects of traffic operation, traffic safety, and traffic behavior.

• 한국응급구조학회지
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• 제4권1호
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• pp.95-100
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• 2000

This is a study to evaluate the effects of the safety of ambulance driving and traffic accidents and to provide statistic information for the various factors to reduce the ambulance traffic accidents. The major instruments of this study were Korean Self-Analysis Driver Opinionnaire. This Questionnaire contains 8 items which measure drivers' opinions or attitudes: driving courtesy, emotion, traffic law, speed, vehicle condition, the use of drugs, high-risk behavior, human factors. The total of 145 divers were investigated ambulance drivers in Taejon City and others(6 City) from 2000. 5. July to 2000. 11. July. The data were analyzed by the path analysis - with SPSS and AMOS package program. The result are as follows : 1. It have suggested that risk factors of ambulance traffic accident much affected with emotion and speed control on safety ambulance driving(Y(Accident) = $0.88{\times}1$(Emotion Control) + $0.92{\times}2$(Speed) - $0.46{\times}3$(Traffic Law)+E). 2. It have suggested that risk factors of ambulance traffic accident much affected with emotion and speed control on safety ambulance driving(Y(Accident) = $0.398{\times}1$(Emotion Control) + $0.500{\times}2$(Speed) - $0.263{\times}3$(Traffic Law)+E) by coefficiecial structural analysis.

• 한국ITS학회 논문지
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• 제5권1호
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• pp.55-63
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• 2006

차량의 과속은 도시부 도로에서 번번하게 일어나는 교통사고의 중요한 원인 중 하나이다. 교통사고의 감소를 위하여 설치하는 교통통제창치의 일종인 과속경보장치(DFS)는 국내에서는 차대사람 교통사고를 예방하기 위하여 점차 다양한 곳에 적용을 확산해나가고 있다. 본 연구에서는 이 교통통제장치의 효과가 어느정도인지를 파악하기 위하여 설치전후로 첨두시간과 비첨두시간대로 나누어 필드 조사를 수행하였고, 수집자료의 분석에는 차량평균속도 및 속도분산을 포함한 여러 가지 종속변수에 대하여 실험결과에 대한 통계적 검증과 함께 논의 되어졌다. 따라서 본 연구에서는 사고감소 및 교통안전도 향상을 위한 교통통제장치로써 과속경보장치(DFS)가 단속에 의한 강제적 방법을 사용하지 않고도 교통류의 속도를 효과적으로 통제하여 보다 안전한 보행환경을 제공하고, 사고율을 낮춤으로써 교통안전도를 향상시키는 것으로 파악되었다.