• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.5
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• pp.26-37
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• 2009

This paper suggests a sensor's placement method for detecting the dilemma zone problem when real-time driver's safety service is provided at signalized intersections by multiple pointed traffic sensors using USN environments. For detecting the dangerous situations from vehicles accelerating through yellow intervals, red-light running and stopping abruptly like as dilemma zone problem, VISSIM(microscopic, behavior-based multi-purpose traffic simulation program) is used to perform a real-time multiple detection situation by changing the input data like as various inflow-volume, design speed change, driver perception and response time. As a result, the optimal interval of traffic sensors is 20~27m, and the initialized sensor location from stop-line is different according to road design speed. Moreover, the pattern of detection about dilemma zone is also different according to inflow-volumes. This paper shows that the method is useful to evaluate the sensor's placement problem based on micro-simulation and the results can be used as the basic research for USN services.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.96-109
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• 2019

Roundabouts are actively installed to reduce unnecessary congestion and reduce traffic accidents. However, it is difficult to apply more than 450 cars per, hour. In addition, there is a downside to the concentration of delays in certain directions depending on traffic conditions. To compensate for these shortcomings, signal metering was introduced. Signal metering is a technique that gives red signals to adjacent left traffic flow in the event of a delay in a particular direction. The purpose of this study is comparing the effect of signal metering in conventional and special types (turbo roundabout, flower roundabout) of roundabout. VISSIM API is used for analysis. The analysis result show that only conventional roundabout signal metering algorithm reduce delay time per vehicle. As the result of the turbo roundabout and flower roundabout signal metering algorithm increase delay time per vehicle, signal metering algorithm can be applied in conventional roundabout.

• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.113-124
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• 2009

This paper suggests a new approach for providing information for driver safety at signalized intersections. Particularly dangerous situations at signalized intersections such as red-light violations, accelerating through yellow intervals, red-light running, and stopping abruptly due to the dilemma zone problem are considered in this study. This paper presents the development of a dangerous vehicle determination algorithm by collecting real-time vehicle speeds and times from multiple point detectors when the vehicles are traveling during phase-change. For an evaluation of this algorithm, VISSIM is used to perform a real-time multiple detection situation by changing the input data such as various inflow-volume, design speed change, driver perception, and response time. As a result the correct-classification rate is approximately 98.5% and the prediction rate of the algorithm is approximately 88.5%. This paper shows the sensitivity results by changing the input data. This result showed that the new approach can be used to improve safety for signalized intersections.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.6
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• pp.37-48
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• 2020

Eight colors prescribed by the Enforcement Rules of the Road Traffic Act and the group standard were tested to secure the minimum recursive reflectance performance standards when drying and wetting. The results were calculated to be 260.8 (mcd/㎡·lux) when drying white and 154.6 (mcd/㎡·lux) when wet. Yellow was 67% compared to the white reflective performance when drying. Wet poetry was 79 % and 59 %, respectively. In the case of blue, it was 64% in the case of white versus 72% in the case of white. Wet poetry was 63 % and 72 %, respectively. The range of changes in reflective performance during wetting was higher than when drying, and the absence of glass grains was similar to the previous results. The new colors also have a standard value of more than 50% compared to the white color in red, orange, pink, light green, and green. Based on this, it was estimated that the minimum reflective performance criteria according to the color of the road markings would form the basis for the enforcement rules of the Road Traffic Act.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2485-2492
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• 1997

Nowadays the traffic conditions have been getting worse due to continuous increase in the number of vehicles. So it has become more important to manage traffic signal lights efficiently. Recently fuzzy logic is introduced to control the cycle time of traffic lights adaptively. Conventional fuzzy logic controller adjusts the extension time of current green phase by using the fuzzy input variables such as the number of entering vehicles at the green light and the number of waiting vehicle during the red light. However this scheme is inadequate for an intersection with variable traffic densities. In this paper, a new FLC with asymmetric membership functions that reflects more exactly traffic flows than other FLCs with symmetric ones regardless of few control rules is propsed. The effectiveness of the proposed method was shown through simulation of a single intersection. The experimental results yielded the superior performance of the proposed FLC in terms of the average delay time, the number of passed vehicles, and the degree of saturation.

• Journal of Korean Society of Transportation
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• v.19 no.3
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• pp.7-18
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• 2001

The pedestrian signal systems operating presently could provide more time for the pedestrian to cross the street than the previous system, but it would increase the cycle length and cause longer delays at the signalized intersections. For instance, more than 80% of traffic signals would have to have the cycle length increased by 10sec in Daegu Metropolitan areas. Therefore. the purpose of this study is to propose a pedestrian traffic signal time that not only maintains the safety of the pedestrian but also reduces the traffic cycle length. The proposed pedestrian signal time is set to enable enough time for the elderly to cross and the flashing time is set low enough to deter the ordinary person. This new pedestrian signal time can reduce the traffic cycle length at intersections and prevent the Pedestrian crossing during flashing time. In addition to the flashing green should be changed to flashing red to warn the pedestrian he should not begin crossing as opposed to the flashing green which suggest he could cross. In this study, the speed of 1.1m/sec and 0.85m/sec are applied to the new proposed signal time for normal and elderly person respectively after analyzing data collected at Daegu Metropolitan area.

• 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 the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.296-301
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• 2020

Three types of traffic signal systems are two-color signal systems that flash red and green and are mainly used on crosswalks, next, three-color equalization systems mainly used at T-shaped intersections with red and yellow lights and a green arrow, and third, four-color intersections that generally have red, yellow and green colored lights and a green arrow. In what is known as the "dilemma zone" area, a driver collects information that influences his/her decision whether to stop, speed, tail, interrupt, or violate a traffic light, depending on the intersection width, vehicle speed, cognitive response time and reference yellow signal time. This study examined the impact of changes in the length of the dilemma zone areas based on changes in yellow signal times, the speed of the intersection passages, and signal lamps. Downward adjustments of 50km/h and 60km/h affected yellow signal time. The yellow signal time increased by 0.1 to 2.3[s] due to this effect and the dilemma zone area increased by 1.22 to 26[m]. The driver of the dilemma zone could quickly decide to reduce the time remaining of the straight (3color, 4color) green signal to reduce the potential of a traffic accident at the intersection traffic. Safe entry of red (LED palm) and left-turn signals for entering flashed at the intersection and operated at midnight.

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.91-100
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• 2008

Pedestrians are exposed to accidents as a result of the lack of understanding the meaning of a flashing green signal. This study was to designed to relate changes of pedestrians' crossing characteristics as a functions of flashing green signal timings. A field survey was conducted to collect pedestrian preference and safety and it was examined by signal operation experiment. Two versions of new pedestrian signal timings were compared to the existing pedestrian signal timings. The results indicated that the number of pedestrians who starts to cross during flashing green signals was significantly decreased when flashing green signals started at 1/2 or 2/3 point of crossing. However, the number of pedestrians who remain in the crossing during red signals was significantly increased when flashing green signals started at 2/3 point of crossing. This study concludes that starting flashing green signals at 1/2 point of crossing is the safest. Also, implication and directions for its practical relevance were discussed.

• Journal of Korean Society of Transportation
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• v.21 no.5
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• pp.41-48
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• 2003

Korea Claim Adjustor Association(KCAA) defines the near pedestrian crossing accidents as those accidents that occurred in the area within 25m from pedestrian crossing on the arterial road and within 15m from pedestrian crossing on other classes of road. Accidents between pedestrian crossing and stop line are classified as the accident near pedestrian crossing. Reviewing of current statute and court precedent, three kinds of traffic accidents which are accidents occurred in the pedestrian crossing. near pedestrian crossing and the area between pedestrian crossing and stop line. should be distinguished by different pedestrian contributory negligence. To find out how different they are. we surveyed transportation society members about the contributory negligence of traffic accidents between pedestrian crossing and stop line and the results are as follows : (1) The current two classification of pedestrian crossing accidents and near pedestrian crossing accidents should be changed to three classification of pedestrian crossing accidents that includes accidents on pedestrian crossing, near pedestrian crossing and between pedestrian crossing and the stop line. (2) For the pedestrian's contributory negligence, the least reasonability to pedestrian is accident on the pedestrian crossing. The next one is the accident between pedestrian crossing and stop line and the last is the accident near pedestrian crossing. (3) Pedestrian contributory negligence for accident by space is recommended as 〈table 8〉, 〈table 9〉, 〈table 10〉. (4) Contributory negligence rate of the accident on the pedestrian crossing during red light should be modified to be less than that of near pedestrian crossing.