• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.589-599
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• 2021

Purpose: A reliable indicator of congested traffic speed is essential in providing the information of traffic flow states about motorway sections. The aim of this study is to propose an adaptive indicator of congested speed which is employed for deciding the traffic flow states for individual motorway sections using disaggregated section-based speed data. Method: Typically, the state of traffic flow is categorized into the three: uncongested, mixed, congested states. A method, presented in this study, was developed for identifying boundary speed values of road sections through categorizing the three traffic flow states with individual vehicular speed values. The boundary speed state of each road segment is determined using the speed distributions of mixed and congested traffic states. Result: Analysis results revealed that boundary speed values between mixed and congested states for road sections were similar to those of US and EU criteria (i.e., 48.28~66.0 kph). This indicates that boundary speed values could be different according to road sections. Conclusion: It is expected that the method and indicator, proposed in this study, could be efficaciously used for providing ad-hoc real-time traffic states and computing traffic congestion costs for motorway sections in the era of big data.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.121-132
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• 2018

Weather is an important factor affecting roadway transportation in many aspects such as traffic flow, driver 's driving patterns, and crashes. This study focuses on the relationship between weather and road surface condition and develops a model to estimate the road surface condition using machine learning. A road surface sensor was attached to the probe vehicle to collect road surface condition classified into three categories as 'dry', 'moist' and 'wet'. Road geometry information (curvature, gradient), traffic information (link speed), weather information (rainfall, humidity, temperature, wind speed) are utilized as variables to estimate the road surface condition. A variety of machine learning algorithms examined for predicting the road surface condition, and a two - stage classification model based on 'Random forest' which has the highest accuracy was constructed. 14 days of data were used to train the model and 2 days of data were used to test the accuracy of the model. As a result, a road surface state prediction model with 81.74% accuracy was constructed. The result of this study shows the possibility of estimating the road surface condition using the existing weather and traffic information without installing new equipment or sensors.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.113-116
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• 2009

보다 바람직한 운전 경험을 제공하기 위하여, 운전자의 감성에 영향을 미치는 요인에 대한 관심이 높아져 가고 있다. 본 연구에서는 운전자의 운전 시의 기분 혹은 감정상태에 영향을 미치는 외부요인으로 도로 소통 상황, 계절, 날씨, 운전 시각, 운전 지역을 추출하였으며 운전자 개인의 감정상태를 결정짓는 주관적이고 심리적인 요인은 배제하였다. 운전 경력 3 년 이상의 운전자를 대상으로 감성 상태는 긍정/부정, 흥분/안정의 2 가지 축으로 나뉘어 측정하였다. 운전자의 무드는 중립을 기준으로 양 극단보다는 중립에 가까운 상태에 주로 분포하였는데 긍정/부정에는 각각 고루 분포한 반면, 흥분/안정에서는 안정 쪽에 더 많이 분포한 것을 알 수 있었다. 또한 다섯 가지 외부 요인들이 모두 운전자의 무드에 영향을 미쳤으며 도로 소통 상황이 긍정/부정과 흥분/안정 모두에서 유의미한 차이를 보였다. 감성의 긍정/부정 축에서는 계절, 날씨, 소통 상황, 그리고 운전 지역이 유의미하였으며, 감성의 흥분/안정 축에서는 운전시간과 소통 상황이 유의미하였다. 본 연구의 결과를 확장시켜 운전자의 감성에 영향을 미치는 외부 요인들을 데이터베이스화하여 운전자를 위한 다양한 제품 및 서비스 개발에 활용될 수 있을 것으로 기대한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.116-125
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• 2014

Road conditions can provide important information for driving safety in driving assistance systems. The input images usually include unnecessary information and they need to be analyzed only in a region of interest (ROI) to reduce the amount of computation. In this paper, a vision-based road ROI determination algorithm is proposed to detect the road region using the positional information of a vanishing point and line segments. The line segments are detected using Canny's edge detection and Hough transform. The vanishing point is traced by a Kalman filter to reduce the false detection due to noises. The road ROI can be determined automatically and adaptively in every frame after initialization. The proposed method is implemented using C++ and the OpenCV library, and the road ROIs are obtained from various video images of black boxes. The results show that the proposed algorithm is robust.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.3
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• pp.279-292
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• 2022

Unexpected anomalies in the geotechnical investigation at design stage may cause problems during tunnel excavation. Therefore, it is important to predict the ground condition ahead of a tunnel face during tunnel excavation in order to prevent tunnel collapse. Despite the fulfillment of an electrical resistivity survey at the tunnel face, the existing electrical resistivity survey program can produce distorted results by the limitation of tunnel modelling. In this background, this study develops a modelling program for an electrical resistivity survey considering the tunnel shape. Numerical simulation and inverse calculation were performed for the electrical resistivity survey in the tunnel using the developed program. As a result, it was proved that the developed program could predict accurately the anomalous object's location and condition ahead of the tunnel face.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4D
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• pp.291-303
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• 2012

In order to lead safe driving, it is better to provide dynamic and detailed information on how the driver using the relevant road should behave as concerning movements of individual car rather than providing monotone and static information of reducing of speed to unspecified drivers. Assuming road and communication of highway where real-time collection and transfer of information on vehicles and road traffic status is possible, the purpose of this study was to provide real-time safe distance by considering road traffic condition such as road condition and driving condition, travel speed and distance between preceding/following vehicles. We intended to provide basic information about dangerous situation by defining different values of condition based column ($C_{condition}$) in accordance with the road surface condition, based on which Real-time Safety Distance Index(RSDI) is to be calculated comprehensively reflecting speed of preceding and following vehicles, distance between vehicles, vertical alignment and road surface condition on the scope of expression column ($C_n$). We intended to enable the driver to secure safety by providing the calculated Real-time Safety Distance Index (RSDI) so that the driver can intuitively sense and sufficiently cope with a dangerous situation where collision of vehicles may occur. The calculated RSDI value is comprised of 30 unit columns and will be provided to the driver being divided into risk evaluation grades of 3 predetermined steps, 'warning', 'dangerous' and 'normal'.

• 한국지형공간정보학회:학술대회논문집
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• 2003.09a
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• pp.163-168
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• 2003

급속한 도시화와 교통 수요의 증가로 인해 각종 도로 정보가 빠르게 변화하고 있어 이에 대한 정보들의 추출, 수정 또는 보완의 중요성이 커지고 있다. 도로 정보 및 도로 파손 상태 정보를 이용하면 도로를 효율적이고 경제적으로 유자 관리할 수 있고, 수치지도 및 GIS 분석의 입력자료로서 사용될 수 있다. 본 연구에서는 분당지역의 항공사진을 이용하여 반자동으로 도로를 추출하였다. 항공사진에 탑햇 필터(top-hat filter)를 적용하고 적절한 임계값을 설정하여 후보 개체를 선택하고 모양 유사성을 고려하여 차로분리선만을 선택함으로써 효율적으로 차로분리선을 추출하였다. 추출된 차로분리선을 연결하고 중심선을 구함으로써 도심지역의 도로를 추출할 수 있었다.

• Journal of Korean Society of Transportation
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• v.30 no.1
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• pp.75-83
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• 2012

This study is to find a shortcoming embedded in the current Korean Highway Capacity Manual (KHCM) on reflecting a heavy vehicle effect to the highway capacity. The KHCM suggests to handle the percent heavy vehicle to deal with its effect to a capacity regardless of density levels. Authors hypothesized in this study that the effect of heavy vehicles would vary at different levels of traffic density - the effect would be comparably insignificant when a density is low and it becomes comparably significant when it becomes high. Field data from a freeways located in Seoul were collected for 360 hours (15 days) and categorized them into a set of operation conditions grouped by 15 minutes and by the LOS density levels. Comparison between the field measured and the estimated by the KHCM method showed that the KHCM method overestimated the effect of heavy vehicles in LOS B and C but underestimated in LOS E. The results suggested that there be a difference pattern from the one the KHCM expected and brought discussion on further studies.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.157-163
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• 2010

It is well known that weather conditions are closely related with the number and severity of traffic accidents. At present, installation of safety countermeasures including systems is common approach to reduce the damage of traffic accidents at expressways. In this study, the differences of causation factors to influence traffic accidents considering road alignment characteristics and weather conditions. In order to identify the relationship between road and weather conditions, discriminant analysis has been performed with 500 traffic accident data at expressways. Weather conditions are divided into several categories such as snow, sunny, rain, fog, and cloud. Also, road conditions such as types of pavements, grades are analyzed. As the results, major impacting road conditions to traffic accidents are concrete pavement and 3% or more down grades. In these road conditions, visible distance will be reduced and actual braking distances will be increased. This study shows that the expressway sections under concrete pavement and down grades should be more cautious than other sections. It also shows that fog condition is the mose dangerous situation in terms of traffic accidents.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.119-128
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• 2008

On the many highways, severe traffic congestions happen chronically and make traffic problems like reduction of mobility because of rapid increase of vehicles though road construction has been last. In order to solve these traffic problems, it is needed to find the trend and the symptom of traffic congestion and to analyze the cause of congestion and the(spatial) range affected by congestion. To develop the traffic condition monitoring index prior to doing all those things is most important. With this reason, many countries including U.S. had been developed the congestion criteria and indices. In this paper, applicability and characteristics of existing traffic congestion indices were considered and the direction for development of a new traffic condition index was suggested to achieve an effective traffic management.