• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.115-126
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• 1999

Past nears many Studies have been described for present state and forecasted for the future phenomena in various areas. Many theories and methodologies in transportation have been developed and applied by researchers and planners. On the other hand, many theories and methodologies had disappeared caused by their critical limitations. One of this cause that was discovered of the Chaos in traffic flows. The occurrence of Chaos in traffic flows has affected to the traffic volume and decreased significancy of a simulation result of a specific traffic flow. According to this fact, long-term forecast of traffic flow is difficult, moreover a butterfly effect impedes development and establishment of transportation model. A methodology to solve Chaos character in traffic flow can be able to provide more effective transport planning. This study tackles to enhance and revise the existing theories for the traffic flow applying Chaos theory to estimating travel time.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.4
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• pp.107-115
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• 2011

Since 2009 The Korean National Police Agency has been pushed "permissive left-turn" forward in order to making progress in Korean traffic operations system. Preceding researches manuals and guidelines present 6 standards(# of accidents # of lanes, pedestrian volume sight # of permissive left-turn lanes vehicle volume) as installation permissive left-turn. But in practical affairs it is most important that secure enough Gap-time between permissive left-turn vehicle and opposite through lane vehicle to make permissive left-turn vehicle move safer and more efficiently. This study suggests applying gap acceptance theory in microscopic model to permissive left-turn installation standards. Analysis methods of this study are field data survey statistical analysis and microscopic simulation analysis. This study collected field data by using AVI recording and measured permissive left-turn vehicle intersection passing time(T1) and against the opposite through lane vehicle Gap-time(T2). And statistical analysis performed about two values that measured before to predict the functionality between T1 and T2. These studies to overcome the limit of sample size carried out a microscopic simulation(VISSIM) plan and collect more samples to input statistical analysis.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.27-34
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• 2009

The operational effect of traffic signal control improvement was evaluated using the Two-Fluid Model. The parameters engaged in the Two-Fluid Model becomes food indicators to measure the quality of traffic flow due to the improvement of traffic signal operation. A series of experiment were conduced for the 31 signalized intersections in Uijeongbu City. To estimate the parameters in the Two-Fluid Model the trajectory informations of individual vehicles were collected using the CORSIM and Run Time Extension. The test results showed 35 percent decrease of average minimum trip time per unit distance. One of the parameters in the Two-Fluid Model is a measure of the resistance of the network to the degraded operation with the increased demand. The test result showed 28 percent decrease of this parameter. In spite of the simulation results of the arterial flow, it was concluded that the Two-Fluid Model is useful tool to evaluate the improvement of the traffic signal control system from the macroscopic aspect.

• Journal of Korean Society of Transportation
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• v.31 no.6
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• pp.3-11
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• 2013

Under the consumption of bad weather situation affects traffic flows, the study scope is focused on highway capacity and speed variations among other highway traffic flow characteristic changes according to snowfall density. Thus, this study carried out through the data collection and statistical analysis by focusing on capacity and speed changes. Traffic volume, speed and density were selected as factors to explain the property change of a traffic flow for analysis, and 7 basic sections such as 3 highways in Gyeonggi-do and 4 highways near the meteorological observatory were selected as survey points for data collection. Snowfall levels were classified into 3 steps(Light, Medium, Heavy Snow) to analyze the capacity change by snowfall levels. As a result of analysis, the change of capacity depending on snowfall levels decreased 13.2% in case of light snow compared to a good weather, 18.6% in case of medium snow and 32.0% in case of heavy snow, so the capacity reduction rate increased as the snowfall level increased. The worsening weather appeared to have a very big possibility to act as a factor to reduce the operational efficiency of a road, so a road design and operation method considering this should be presented in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3D
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• pp.329-334
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• 2009

The various behaviors of vehicular traffic flow are generated through both car-following and lane-changing behaviors of vehicles. Especially lane-usage varies by lane-changing behaviors. In the area of microscopic vehicle simulation, a lane-changing model connected to a car-following model parallel is essential to generate both various traffic flows relationships and laneusages. In Korea, some studies on car-following models have been reported, but few studies for lane-changing models stay in the beginning stage. In this paper, a two-lane changing model for the simulation modeling of large freeway network is introduced. The lane-changing model is developed based on CA (Cellular Automata) model. The developed model is parallel combined with an existing CA car-following model and tested on a closed link system. The results of simulation show that the developed model generates the various behaviors of lane usage, which existing CA lane-changing models could not generate. The presented model is expected to be used for the simulation of more various freeway traffic flows.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.195-202
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• 2011

The purpose of this study is to estimate the capacity of two-lane freeway work zone blocking one lane using traffic flow models of each vehicle-type. Firstly, three traffic flow models of three different vehicle-types were developed using the data collected from each at the beginning and the ending point of the work zone. For each model, the maximum flow rate of three vehicle-types were calculated respectively. Maximum flow rate at the work zone was recalculated using passenger car equivalent value and percentage of vehicle-type. Secondly, traffic flow model using passenger car equivalent volume data was developed using the data collected from each at the beginning and the ending point of the work zone. Maximum flow rate for the work zone was calculated along. Two values of maximum flow rates through the work zone were compared and evaluated as the capacity of the work zone. This study found that the maximum flow rate of the work zone at the beginning point was less than that at the ending point because of impedance such as lane changing behaviors before entering the work zone. The capacity of two-lane freeway work zone blocking one lane was estimated 1,800pcphpl.

• Journal of Korean Society of Transportation
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• v.23 no.4 s.82
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• pp.57-69
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• 2005

The goal of this paper is to develop freeway Origin-Destination (OD) demand estimation model using real-time traffic data collected from Freeway Traffic Management System (FTMS). In existing research, the micro-simulation models had been used to get a link distribution proportion by time process. Because of hi-level problem between the traffic flow model and the optimal OD solution algorithm, it is difficult for the existing models to be loaded at FTMS. The formulation of methodology proposed in this paper includes traffic flow technique to be able to remove the bi-level problem and optimal solution algorithm using a genetic algorithm. The proposed methodology is evaluated by using the real-time data of SOHAEAN freeway, South Korea.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.170-172
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• 2017

표준형 부표류는 2001년에 개발되어 현재까지 15년동안 해상교통환경 및 해양기상여건이 변화하고 관리자의 운영경험이 축적되었으며 최근 첨단 기술 및 신소재가 개발되어 표준형 부표류의 개선이 필요하다. 표준형 부표류의 구조적 및 관리운영적 측면의 현황과 문제점을 분석하고 해양선진국의 사례를 조사하는 등 표준형 부표류를 개발하고 개선하기 위한 연구 개발이 요구된다.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.149-158
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• 2002

For the purpose of preciously describing real time traffic pattern in urban road network, dynamic network loading(DNL) models able to simulate traffic behavior are required. A number of different methods are available, including macroscopic, microscopic dynamic network models, as well as analytical model. Equivalency minimization problem and Variation inequality problem are the analytical models, which include explicit mathematical travel cost function for describing traffic behaviors on the network. While microscopic simulation models move vehicles according to behavioral car-following and cell-transmission. However, DNL models embedding such travel time function have some limitations ; analytical model has lacking of describing traffic characteristics such as relations between flow and speed, between speed and density Microscopic simulation models are the most detailed and realistic, but they are difficult to calibrate and may not be the most practical tools for large-scale networks. To cope with such problems, this paper develops a new DNL model appropriate for dynamic traffic assignment(DTA), The model is combined with vertical queue model representing vehicles as vertical queues at the end of links. In order to compare and to assess the model, we use a contrived example network. From the numerical results, we found that the DNL model presented in the paper were able to describe traffic characteristics with reasonable amount of computing time. The model also showed good relationship between travel time and traffic flow and expressed the feature of backward turn at near capacity.

• Journal of Korean Society of Transportation
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• v.23 no.7 s.85
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• pp.125-136
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• 2005

The goal of this paper is to develop freeway Origin-Destination (OD) demand estimation model using VDS and AVI data. The formulation of methodology proposed in this paper includes traffic flow technique to be able to remove the bi-level problem and optimal solution algorithm using a kalman filter algorithm. The proposed dynamic OD estimation model use ilk and off-ramp volumes collected from VDS and partial OD collected from AVI data to raise the accuracy of dynamic OD estimation. The proposed model is evaluated by using the real-time data of SOHAEAN freeway, South Korea. The result of the proposed dynamic OD estimation model based on VDS and AVI data is better than that of based on VDS data. The more AVI systems are equipped at on and off-ramp, the more excellent result of estimation accuracy is expected.