• Journal of Navigation and Port Research
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• v.37 no.5
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• pp.535-541
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• 2013

Expressways are built to provide for high levels of safety and efficiency in the movement of large traffic volumes at high speeds. However, Gyeongbu and Namhae expressways in the country which are often suffering from the transportation problems with increased import and exoprt cargo trucks including the container vehicles are the major expressways having the Busan Port as the origin and destination regions, and are required to study the expressway traffic characteristics for reducing the transportation problems. We therefore attempted to suggest the expressway density predictive model through the correlation analysis between lane occupancy and mean density at the 8-lane basic segments of the above major expressways in the country.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.73-81
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• 2007

The purpose of this paper is to perform a basic study on the interaction between lanes, which can be achieved through analyzing traffic breakdown at the microscopic level. Using aerial photographic data for the microscopic analysis, this study analyzed the characteristics of traffic flow at a merging area. This research produced aggregated traffic data such as flows, speeds, and densities in 30 second intervals by lane for the macroscopic analysis and individual headway data by lane for the microscopic analysis. The paper contains an analysis of lane characteristics through flows, speeds, densities, and headway variations and also investigates the influence of ramp flows on mainline flows with space-time diagrams. Firstly, the merging area in this study is divided into three sections: before-merging, during-merging, and after-merging. The transition process was analyzed at each lane. Secondly, the breakdown was observed in detail with data divided in 50-foot units. The breakdown was checked through the relationships between ramp and freeway mainline flows, various techniques were proposed to analyze the breakdown, and the formation of breakdown was introduced as three stages in this study. In the near future, the findings of this study could contribute to determining the dynamic capacity on freeways by easily understanding changeable traffic breakdown patterns over time and space.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.10B
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• pp.1436-1443
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• 2001

본 연구는 고속도로에 설치된 CCTV 카메라에서 교통량, 속도, 점유율 등의 교통정보를 수집하기 위하여 검지영역을 자동으로 설치하는 알고리즘을 제안한다. 이를 위하여 교통정보센터에 설치된 콘트롤러에서 CCTV 카메라의 Pan, Tilt, Zoom 요소값을 보내면 이 값만큼 CCTV 카메라가 panning, tilting이 되고, 이에 따른 변화된 영상이 교통정보센터로 전송이 된다. 기존의 연구로는 영상 내에서 도로를 추출하기 위하여 차 영상(difference image)에 의한 도로추출방법과 윤곽선 추출방법에 의한 도로추출 방법이 있으나, 전자는 도로를 추출하는데 있어서 시간이 많이 소요된다는 문제점이 있으며, 후자는 정확한 도로를 추출하지 못한다는 문제점이 있다. 이러한 문제를 해결하기 위하여 본 연구에서는 우선 각 차로 상의 직선의 방정식을 구하고, 이 직선의 방정식에서 CCTV 카메라가 Panning, Tilting하는 중심점을 찾은 다음 CCTV 카메라의 Pan, Tilt 값에 의하여 3차원상의 원근비율에 따라 각 차로 별 좌표변환방법을 이용한다. 본 연구를 위한 실험은 고속도로 기흥IC에 15m 높이로 설치된 CCTV 카메라에서 영상을 캡쳐하였으며, 차후 교통량, 속도, 점유율 등 교통정보를 산출하는데 처리 속도를 고려하여 영상의 해상도는 640480픽셀과 256명암값에서 계산되었다.

• Journal of Korean Society of Transportation
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• v.17 no.1
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• pp.29-39
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• 1999

An earlier study of the effect of rain found that the capacity of freeway systems was reduced, but did not address the effects of rain on the nature of traffic flows. Indeed, the substantial variation due to the intensity of adverse weather conditions is entirely rational so that its effects must be considered in freeway facility design. However, all of the data in Highway Capacity Manual(HCM) have come from ideal conditions. The primary objective of this study is to investigate the effect of rain on urban freeway traffic flows in Seoul. To do so, the relations between three key traffic variables(flow rates, speed, occupancy), their threshold values between congested and uncontested traffic flow regimes, and speed distribution were investigated. The traffic data from Olympic Expressway in Seoul were obtained from Imagine Detection System (Autoscope) with 30 seconds and 1 minute time periods. The slope of the regression line relating flow to occupancy in the uncongested regime decreases when it is raining. In essence, this result indicates that the average service flow rate (it may be interpreted as a capacity of freeway) is reduced as weather conditions deteriorate. The reduction is in the range between 10 and 20%, which agrees with the range proposed by 1994 US HCM. It is noteworthy that the service flow rates of inner lanes are relatively higher than those of other lanes. The average speed is also reduced in rainy day, but the flow-speed relationship and the threshold values of speed and occupancy (these are called critical speed and critical occupancy) are not very sensitive to the weather conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.623-631
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• 2011

In this study, a new method which can detect incidents in interrupted traffic flow was suggested. The applied method of detecting the incident is the Latin Square Analysis Method by using traffic traits. In the Latin Square Analysis, unlike other previously tried methods, the traffic situation was analyzed, this time considering the changes in traffic traits for each lane and for each time period. The data used in this study were the data observed in the actual field with fine weather. The traffic volumes, the vehicle speed and the occupancy rate were collected on the interrupted flow road. The data were collected in normal and incident situations. The incidents occurred on the second lane, the time of persistent incidents was set to 10 minutes. The Latin Square Analyses were performed using the collected data with the traffic volume, with the vehicle speed or with the occupancy rate. As a result in this study, in case of detecting the traffic situations with Latin Square Analysis, it will be more successful to apply traffic volume to detect the traffic situations than to apply other factors.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.38-51
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• 2020

A bottleneck and congestion occur when a freeway is closed due to maintenance and construction activities on the freeway. Although various traffic managements have been developed to improve the traffic efficiency at freeway work zones, such as merge control, there is a limit to those controls with human drivers. On the other hand, the wireless communication of connected and automated vehicles (CAVs) enables the operation of advanced traffic management. This study developed a traffic control strategy that integrates Dynamic Merge Control (DMC) and Lane Change Control (LCC) in a CAV environment. DMC operates as an either early or late merge based on the occupancy rate of upstream of the work zone. The LCC algorithm determines the number of vehicles that need to change their lane to balance the traffic volume on open lanes. The simulation results showed that integrated control improves the cumulative vehicle count, average speed upstream, and average network travel time.

• Journal of Korean Society of Transportation
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• v.21 no.2
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• pp.45-60
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• 2003

A median is a safety feature most commonly used to separate opposing traffic on a divided highway. In designing highways, the selection and installation of a median can be a critical part from a safety viewpoint because road crossing accidents are definitely more serious than other accidents. In regard to the important function of the median. the proper countermeasure ought to have been provided and thorough study should have been carried out. In this paper, traffic accident data are analyzed to examine the accident reduction effect of the median, which are gathered from all over 4-lane national roads in Korea. The traffic accident data were categorized into two groups by the existence of a median. For more effective analysis, the data have been classified by accident type, severity. and occurrence time. To compare the effectiveness of median installation, not only the accident frequency but also the accident severity, EPDO. and the occupancy rate of specific accidents have been used as a mode of effectiveness. The analysis of the effectiveness of medians shows that both the accident frequency and the accident severity could decrease by providing a median. Also the section where a median was supplied showed the improvement of overall safety through fewer serious and fatal crashes as well as fewer head-on crashes. Therefore, conclusions can be drawn from results of this study that the median installation is an important means to increase the safety of over 4-lane national roads. This study is expected to provide the reasonability of the median installation by identifying the reduction of traffic accident after the median installation and to play a major role in selecting sections where the median is to be offered.