• 한국ITS학회:학술대회논문집
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• v.2006 no.10
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• pp.18-24
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• 2006

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

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.1 s.9
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• pp.21-30
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• 2006

For urban highway network, traffic control strategy paradigm has been shifted from the private auto-oriented to the public transit-oriented. Introduction of exclusive median bus lanes (EMBL) in Seoul, Korea, has especially accelerated such changes in transportation policy and thus highway environment. Left-turning movement treatment at signalized intersections where EMBL pass through has been emerged as one of the rising problems associated with a current signal head with 4-signal lens, the Korea standard. This study proposes a new signal phase operation scheme for signal operation at an isolated intersection where EMBL pass through. The authors propose to use of an exclusive bus signal head indicating right-of-way of transits on EMBL only. Based on it, three different phase operation scheme were developed for left-turn treatments for traffic control with (1) traffic responsive control mode and (2) time-of-day traffic control mode. In addition, methodologies to design and develop signal maps for the proposed signal phase schemes are also developed. The proposed operation can only be possible when additional uses of signal state relay boards are allowed.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.105-115
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• 2002

For many rears, traffic accident statistics are the most direct measure of safety for a signalized intersection. However it takes more than 2 or 3 yearn to collect certain accident data for adequate sample sizes. And the accident data itself is unreliable because of the difference between accident data recorded and accident that is actually occurred. Therefore, it is rather difficult to evaluate safety for a intersection by using accident data. For these reasons, traffic conflict technique(TCT) was developed as a buick and accurate counter-measure of safety for a intersection. However, the collected conflict data is not always reliable because there is absence of clear criteria for conflict. This study developed objective and accurate conflict criteria, which is shown below based on traffic engineering theory. Frist, the rear-end conflict is regarded, when the following vehicle takes evasive maneuver against the first vehicle within a certain distance, according to car-following theory. Second, lane-change conflict is regarded when the following vehicle takes evasive maneuver against first vehicle which is changing its lane within the minimum stopping distance of the following vehicle. Third, cross and opposing-left turn conflicts are regarded when the vehicle which receives green sign takes evasive maneuver against the vehicle which lost its right-of-way crossing a intersection. As a result of correlation analysis between conflict and accident, it is verified that the suggested conflict criteria in this study ave applicable. And it is proven that estimating safety evaluation for a intersection with conflict data is possible, according to the regression analysis preformed between accident and conflict, EPDO accident and conflict. Adopting the conflict criteria suggested in this study would be both quick and accurate method for diagnosing safety and operational deficiencies and for evaluation improvements at intersections. Further research is required to refine the suggested conflict criteria to extend its application. In addition, it is necessary to develope other types of conflict criteria, not included in this study, in later study.