• Journal of Korean Society of Transportation
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• v.25 no.3
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• pp.19-28
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• 2007

Korea's national highways, which emphasize a high level of mobility, serve primarily intercity travel and are used as a detour for freeways. However. at the present. the highways do not have consistent geometric features or other characteristics: for example. some highways have full access control and others have uncontrolled access. Generally, geometric and traffic conditions affect Pronouncedly travel speeds in the highway sections. This study focused on the effect of signalized intersection relative factors on the speeds: signalized intersection densities, signal phases, and volume levels. The study shows that signalized intersection density was the strongest variable affecting the travel speeds: the speeds held fairly constant over intersection densities below 0.3 intersections/km, decreased sharply through intersection density of 0.7 intersections/km. and appeared constant at the lowest level over intersection densities above 0.7 intersections/km. The results also indicate that the effect of signal and traffic volume levels on the speeds was similar to that of the signalized intersection density.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.663-669
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• 2011

In this study, the optimal length of left-turn lane in permissive left-turn signal system at the signalized intersection which has a left-turn bay is estimated. It is a simulation analysis using the queueing theory that estimate the length of left-turn lane. Traffic density conform to the standards of operating a permissive left-turn system of the Practical Manual Traffic Safety Facilities. And each of a left-turn arrival rate, a left-turn service rate, left-turn average queueing time, for green time average queueing vehicle, for red time average queueing vehicle and average queueing vehicle cycle is calculated. As a result of this study, we would learn how much the space should be secured at the signalized intersection which has a left-turn bay. The methodology using the queueing theory to work out the optimal length of waiting lane in the permissive left-turn signal system was presented.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.2
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• pp.133-141
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• 2021

The probe vehicle penetration rate is a required parameter in the estimation of entire volume, density, and queue length from probe vehicle data. The previous studies have proposed estimation methods without point detectors, which are based on probability structures for the locations of probe and non-probe vehicles; however, such methods are poorly suited to the case of multi-lane streets. Therefore, this study aimed to estimate the probe vehicle penetration rate at a multi-lane intersection and introduce a probability distribution of the queue length of each lane. Although a gap between estimates and observations was found, the estimates followed the trend of observations; the estimation could be improved by the correction factor hereafter. This study is expected to be used as a basic study for the estimation of entire volume, density, and queue length at multi-lane intersections without point detectors.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.1 no.1
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• pp.58-69
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• 2002

Most of the traffic accidents are a rear-end collision and a clash generated in the signalized intersection on the local roads. So, it is demanded that the high-quality of signal control and dilemma zone control. According to the cases generated by foreign countries, we established the strategies which are composed of Volume-Density Control, strategy of the dilemma zone control using R-detector (microwave detector) In Japan and EC-DC Control. MOEs(Measure of effectiveness) are car numbers in the dilemma zone , max-out probability in the safe side and the average stopping delay in the progress side. We choose a signalized intersection in rural highway to analyze the effect of the strategies and practiced an on-the-spot survey. The result of the survey is applied to the basic data in the simulator. Consequently, strategy of the dilemma zone control using R-detector(microwave detector) in Japan is the best effective in the safe side and EC-DC control is the best in the progress side. Based on the result, we developed the effective strategy of the signal control . This strategy is composed of the strategy of Japan and the detector on the stopping line used in the EC-DC control. On the result of the analysis, new strategy is the best effective in two sides.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.127-135
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• 2009

Most traffic information that drivers receive while driving are stored in their short-term memory and disappear within a few seconds. Contemporary modeling approaches using a dummy variable can't fully explain this phenomenon. As such, this study proposes to use utility functions of real-time in-vehicle traffic safety information (IVTSI), analyzing its safety impacts based on empirical data from an on-site driving experiment at signalized intersection approach with a limited visibility. For this, a driving stability evaluation model is developed based on driver's driving speed choice, applying an ordered probit model. To estimate the specified utility functions, the model simultaneously accounts for various factors, such as traffic operation, geometry, road environment, and driver's characteristics. The results show three significant facts. First, a normal density function (exponential function) is appropriate to explain the utility of IVTSI proposed under study over time. Second, the IVTSI remains in driver's short-term memory for up to nearly 22 second after provision, decreasing over time. Three, IVTSI provision appears more important than the geometry factor but less than the traffic operation factor.