• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.5 no.2 s.10
• /
• pp.61-71
• /
• 2006

The main purpose of this study is to search a method for reducing traffic accident at signalized intersections. One of the important factors for this is the Left-turn phase sequence. In 1985, the operational principle of Left-turn phase Sequence was changed from Lagging left-turn to Leading left-turn in Korea. Then there was a resonable motive-no exclusive left turn-lane and narrow intersection. So, it is necessary to evaluate the performance difference between Leading and Lagging left -turn phase Sequence. The process of this study is as follows: $\cdot$ First, all the intersection was divided three parts for analysis the traffic safety: Inside part of an Intersection, Crosswalk, Intersection approach and exit. $\cdot$ Second, a safety analysis was performed by using the concepts of 'Effective interphase Period(EIP)' and 'Conflict method' The Study result is that the benefit of of phase Sequence changes from Leading to Lagging phase were significant. For an example the Accident cost will reduced about 41.8 billion won per year in korea.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.3
• /
• pp.19-26
• /
• 1983

Through traffic utilization of left turn lane constitutes an unique traffic operation at an intersection. Consequently, due to the provision as of current practice, conventional methods which estimate traffic volume and intersection capacity by lane would not be valid for design of signal timings. Through traffic utilization factor of left turn lane is affected by left turn volume and signal timings. The primary purpose of this study is to compare the results from leading left turn green phasing scheme with those from previously studied lagging left turn green phasing scheme in terms of utilization factor and intersection capacity by various left turn volume and signal timings, and thereby optimum signal timing to maximize the capacity at given left turn volume. Leading left turn green phasing increases capacity by 10~15 % as compared with that for current lagging left turn green phasing scheme. The range of optimum cycle length for left turn volume about 150 vph is 180~200 second. This cycle length range and left turn interval are longer than those for the lagging left turn green phasing scheme.

• Journal of Korean Society of Transportation
• /
• v.8 no.1
• /
• pp.25-40
• /
• 1990

This study was undertaken to develop a traffic signal timing method for interconnected and semi-protected-left-turn intersections(the intersections which have left-turn signal but not exclusive left-turn lanes) on four-lane streets for energy saving and to computerize the method for the practical use. For this study, a probability model which could estimate the utilized time of the shared left-turn lane by through traffic during green period was developed based on field studies. The two left-turn treatments, leading and lagging left-turns, were tested for the intersections, and it can be concluded that the leading left-turn was more efficient for the normal urban streets on which through traffic is major traffic. Adopting the leading left-turn macro-models to estimate vehicular average delay and proportions of vehicles stopped at the intersections were developed. Using the two models as well as the idling fuel consumpution rate and the excess fuel consumption per stop-go speed change, a traffic signal timing method for the intersections for energy saving was developed and computerized. The method can be used for more than four-lane streets and for other measures of effectiveness such as minimum delay, minimum stop rates, etc.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.16 no.3
• /
• pp.50-58
• /
• 2017

TPCLT(Twice Per Cycle Left-turn) operation reduces this left-turn 'spill-over' problem on an as needed basis by servicing the protected left-turn movement as a leading and a lagging left-turn. In this study, to evaluate the effectiveness of TPCLT applied to three-legged signalized intersection in Korea, the analysis was carried out using VISSIM and SSAM model analysis. The study was implemented by three cases which are TPCLT operation, non-TPCLT operation and half-cycle operation using VISSIM program. According to the 9-left-turn volume scenario, total delay and travel times of each case was analyzed by VISSIM program. The study result shows more effective applying TPCLT operaion in the present ~ +50% scenario area at the intersection in terms of total delay.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.1D
• /
• pp.1-11
• /
• 2012

The presidential council on national competitiveness and the national police agency have initiated a national project to refresh the road traffic control and operation systems to increase operational efficiency at signalized intersections. It would reduce the number of stops and delay of vehicles at intersections and thus mitigate congestion and emission. Although significant reduction of carbon is expected as a consequential result, such effects has yet been studied since traffic operation was behind of interest in the field of green transportation where planning was mainly involved. This paper delivers the macroscopic effects of carbon reduction of the selected items of the national project: the ones managed by the police agency. The results showed that the studied items yield significant reduction of carbon: pedestrian push button operation, flashing signal operation, progression, lagging left turns, permitted left turn, and actuated left-turn operation would reduce 12.31%, 3.27%, 2.44%, 0.97%, 0.81%, and 0.72% of the total amount of carbon emitted a year in a whole transportation sector, respectively.