• 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.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.1-13
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• 2020

When pedestrians cross a pedestrian crossing during a pedestrian signal, there is a problem that pedestrians are exposed to the danger of traffic accidents due to permissive-left turning and right-turning vehicles. In order to solve this problem, there is an increasing demand to improve the traffic signal system to increase pedestrian safety at the signal crossing. This study aims to examine the feasibility of introducing a leading pedestrian interval(LPI) to prevent conflict between unprotected left and right turn vehicles and pedestrians. In this study, the need for LPI was surveyed by experts and the general public. As a result of the survey, many opinions indicated that the introduction of LPI was necessary. In addition, after selecting the non-protected left and right turn pilot operation targets, LPI was installed on two signal intersections. After installation, the speed analysis of the arrival vehicle in the pedestrian crossing and the violation rate of the pedestrian signal were analyzed. As a result of analysis, when the walking signal was equalized, the speed of the arriving vehicle in the pedestrian crossing was reduced, and the violation rate of the walking signal was improved.

• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.17-28
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• 2009

There are many limitations in dealing with rapidly changing traffic demand in urban cities. Thus recently, traffic operation and management skills are more emphasized rather than the expansion of traffic facilities. In particular, in the interrupted flow formed by signalized intersections, it is quite important to give optimal signal timing to each intersection with consideration of progression. However, as fixed signal times per direction can affect passing capacity in signalized intersections, the present four-signal phase including a left-turn signal has many limitations, including reduction of directional road capacity when traffic demand is increases dramatically during peak hours. Because of this problem, lots of studies about internal metering techniques for oversaturated signal control skills have progressed but these techniques are not used widely due to the absence of detectors for queue sensing in real-time signal control systems. In this research, a new methodology called the "restrictive left-turn signal control", which is already used at the intersection above Samsung subway station, is suggested in order to reduce control delay of urban arterial roads. The restrictive left-turn signal control allows a driver to make a U-turn and then a right turn instead of turning left in that intersection. With this change, the restrictive left-turn signal control can contribute to increased intersection capacity by reducing the number of signal phases and maximizing the through phase time. However, road structure and traffic conditions at the target intersections should be considered before the adoption of the proposed signal control.