• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.57-71
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• 2009

Due to increasing interest in dispersion of traffic flows through providing traffic information, there has been much research of driver behavior and effectiveness of diversion. In this paper the authors intend to analyze how a diversion was determined and its effects through correlation analysis between diversion rates estimated by actual surveys and the traffic conditions. Through speed-flow analysis, the diversion mechanism was found. When travel speed decreased, detour volume increased. Then when the traffic volume was decreased through an increase of diversion and traffic conditions got better, the detour volume decreased again. In addition, the authors found negative correlation between the diversion rate and travel speed through correlation analysis. It shows that there were various relationships between diversion rates and traffic conditions according to congestion level and direction of traffic. Finally, it is suggested that the regression equation for calculating the diversion rate with the traffic flows, travel speed, and travel time as variables has a coefficient of determination of 38.5%. It means that traffic conditions on expressways take about 40% of driver's decision-making for diversion.

• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.79-88
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• 2008

VMS based dispersion of traffic flows enables to decrease delay and congestion. Such being the case, there has been growing interests in VMS operation strategy. The strategy is based on driver's behavior or diversion rate. However, it was not easy to obtain each in practice. The diversion rate, thus far, was investigated by stated preference analysis or simulators. As an alternative, in this paper, a new method to obtain diversion flow rate was suggested using the toll collection system and freeway traffic management system data. A large gap of diversion rate between stated preference analysis and field survey was observed. Out of surveyed 8 tollgate data, the diversion rate was about 7% and was quite lower compared with that of 21%${\sim}$87% from stated preference analysis or simulators. With this at hand, a more careful information provision strategy should be devised and employed to correctly account this kind of differences.

• Journal of Korean Society of Transportation
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• v.18 no.4
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• pp.41-50
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• 2000

신호교차로에서 맨 우측차로의 대부분이 우회전 공용차로로 사용되는데 도로용량편람에서 우회전이 불가능한 보행자 횡단시간 비율$(f_c)$은 공용차로의 용량을 결정하는 우회전보정계수$(f_{RT})$의 산정시 중요한 요소가 된다. 그러나 이에 대한 국내의 연구는 미미하여 연구의 필요성이 있다고 생각된다. 본 연구는 유입부의 직진신호시간을 위주로 교차방향 횡단보도 내의 보행자수와 우회전차량의 통과여부를 촬영하여 분석하는 방법으로 진행되었으며, 우회전 차량이 교차도로의 보행자 횡단시간에 보행자와의 상충으로 우회전하지 못하는 시간 비율을 산정함에 있어서 횡단보도의 보행자수에 따라 우회전 차량의 통과율을 구하고 이로부터 횡단보도 보행신호시간동안에 우회전이 불가능한 시간비율을 산정했다. 연구결과는 우회전이 불가능한 시간비율이 시간당 보행자수(양방향)가 500인/시~1,500인/시로 변할 때 0.78에서 0.94사이의 값을 가지며 한국도로용량편람에서 제시한 값 0.3에서 0.9보다는 대체로 큰 것으로 나타났다. 따라서 한국용량편람에서 얻은 우회전차로의 용량은 과대 평가되는 경향이 있다.

• Journal of Korean Society of Transportation
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• v.19 no.4
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• pp.73-84
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• 2001

Korean Highway Capacity Manual applies 7 adjustment factors to estimate saturation flows at signalized intersections. Among the adjustment factors, the right-turn adjustment factor uses equation hard to understand and requires complicated computing process comparing other adjustment factors. Thus. this study was conducted in order to suggest a new technique of estimating the right-turn adjustment factor which is easy to understand and simple to computer by having reasonable degree of accuracy. In this study the right-turn saturation flow ratios which are important in estimating the factor are suggested and the equation to estimate the volume of right-turn on red signal(RTOR) is developed based on observed data. The right-turn saturation flow rates can be estimated according to turning radius and number of lanes of crossing road dividing right-turn lanes into canalized and uncanalized lanes. The RTOR volume is estimated using the proportion of the time during which RTOR is possible to the whole time of red signal according to the through traffic volume per lane of the approach at signalized intersections. The technique of estimating the right-turn adjustment factor suggested in this study, which follows the HCM2000 of U.S. in principal, first judges the right-turn lane to be used exclusively for right-turn or not by employing the RTOR factor and the judging equation developed in this study. Next, if the right-turn lane is not exclusive right-turn lane, the shared right-turn lane is classified into single lane approach or multi lane approach. Thus, a total of three methods of estimating the right-turn adjustment factor to the three cases are suggested in this study.

• Journal of Korean Society of Transportation
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• v.35 no.1
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• pp.79-89
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• 2017

The purpose of this study is to analyze the current right-turn operation at signalized intersections and suggest appropriate right-turn operation strategy. From field investigation, right-turn signals have not only operated various type and shape, lacking of consistency, but also there was no clear regulations or standards. It could increase drivers' confusion and cause vehicle-to-pedestrian accidents. In order to improve pedestrian safety, there is urgent need to study the regulations and standards regarding to right-turn traffic control. This study suggests appropriate right-turn signal operation strategy. In case of permissive right-turn operation, it should be stated on regulations that red light means right-turn vehicles must stop temporarily at the stop line and then turn right. Necessary conditions for installing right-turn signal for protected operation are that there should have one or more exclusive right-turn lanes and right-turn signal face should contain the lenses with three-color arrow indication. In addition, we assort right-turn operation types as permissive, protected and protected/permissive right-turn and suggest specific signal operation strategy by the types.

• Journal of Korean Society of Transportation
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• v.17 no.1
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• pp.91-102
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• 1999

The objective of this study is to evaluate traffic management strategies using Variable Message Signs(MCS) on urban freeways. It is well known that real-time information on traffic conditions increases driver's comfort, and reduces the risks of accidents if drivers are aware of the traffic situation in advance, they decide whether to divert from the freeway or continue on the planned route. The experimental data collected on the Olympic highway we have shown the following results : 1. when the information on both the congested freeway and uncontested diversion route is displayed on the variable message sign. an additional 1.7 percent of traffic diverted, which results in a 3.7 percent reduction in total travel time. 2 Compared with one Proposed VMS message of 'reduce the speed', the other Proposed VMS message of 'keep speed 70km/h' is found to be much more effective in reducing mean speed.

• Journal of Korean Society of Transportation
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• v.21 no.2
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• pp.17-31
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• 2003

This study is about throughput analysis of the shared right turn lane at signalized intersection with lane width change. It is expected that the increased width of the right turn shared lane causes to increase the volume of right turn on red(RTOR) In this study, the throughput computation is designed to take into account the lost time which is caused by the blocked right turn due to the stop of through traffic. The saturation flow rate of right turn using the rest of lane after through traffic stops is included as well. Results show that the different RTOR volume levels due to the various shared lane width leads to a difference in throughput. For the shared right turn lanes. throughput capacity for various lane widths is bigger than that of the KHCM as much as from 1.1 to 2.1 times.

• 한국ITS학회:학술대회논문집
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• v.2007 no.10
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• pp.156-161
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• 2007

• Journal of Korean Society of Transportation
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• v.33 no.5
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• pp.441-448
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• 2015

This study aims to suggest a reasonable signal operation method for right-turn traffic management. It was found that the right-turn vehicle supplementary signal is currently operated without clear regulations or criteria. It was also analyzed that right-turn supplementary signals are used without consistency, there is a risk of traffic accidents due to the discordance between supplementary signals and traffic signals of forward vehicles, there is a lack of basis for prohibition of a right turn when right-turn vehicle's supplementary signal is red and the flashing red signal is used in a different sense from the law. In order to see the effect of the installed right-turn vehicle supplementary signals on traffic signal violation, a field investigation was conducted. As the result, there was a high proportion of signal violation on the approach lane with right-turn supplementary signals and this means that right-turn supplementary signals hardly influenced the reduction in proportion of signal violation during a right turn. Additionally, a survey was carried out to see if there were differences in driver's interpretation of traffic signals depending on the installation of right-turn supplementary signals. As the result of the survey, there were no differences in interpretation of traffic signals depending on the installation of right-turn supplementary signals or the types of right-turn supplementary signals. A right turn when the signal was red did not lead to serious traffic accidents, so it is thought that there should be a careful consideration of a total ban on a right turn when the signal is red, in order to prevent driver's confusion due to the change of the signal system. Unless there is a disturbance to cars and pedestrians after a temporary stop when the signal is red, there is a need to specify that vehicles must stop temporarily in the Road Traffic Act to facilitate a right turn. What this study finally suggested is to use tri-colored arrow signals for right-turn car supplementary signals to convey a signal to a driver clearly.

• Journal of Korean Society of Transportation
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• v.33 no.3
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• pp.304-314
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• 2015

Detour of metro (subway) in metropolitan area has been regarded as one of inherent elements that make entire metro system less competitive than passenger cars. However, factors affecting detour of metro line is not specified clearly when a new subway system is planned or an existing system is improved. Previous detour-related studies was reviewed for developing 'distance efficeincy evaluation model' for metro as well as its counterpart (i.e. road). Metro line 3 (orange line) of Seoul metropolitan area was applied as a case study. As a results, the most detoured OD segment is Daechi - Apgujeong and its detour factor is 1.93 which means that the distance of the metro is 1.93 times longer distance compared to the distance of the road. The metro line 3 has averagely 20% longer distance compared to road for the identical O/D pairs.