• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.1 s.2
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• pp.53-62
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• 2003

This paper demonstrates the in-vehicle dilemma zone warning system (DZWS) project developed as a part of the Driver Advisory and Collision Warning System in Automated Vehicle and Highway System (AVHS). The DZWS project, one of the Korea national ITS projects in 2000 develops the in-vehicle warning device to support drivers' decision making on whether to stop or to proceed to clear the intersection prior to the onset of yellow signal for avoiding the high risk of collision at signalized intersections through the dedicated short range communication (DSRC). This paper explores the design of optimal communication systems between roadway and vehicles, the operational and functional concepts of dilemma zone warning system based on appropriate approach speeds, and the system integration for field test at two sites of signalized intersections. Findings from the system integration indicated that the system would be implemented in eliminating the dilemma zone relative to approach speeds and in reducing red light violations and intersection collisions through the in-vehicle warning device at signalized intersection.

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.301-308
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• 2008

• Proceedings of the KOR-KST Conference
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• 2007.11a
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• pp.477-484
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• 2007

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1279-1287
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• 2014

The purpose of this study is to develop the U-turn accident model at signalized intersections in urban areas. The characteristics of the accidents which are associated with U-turn operation at 3 and 4-legged signalized intersections was analyzed and the U-turn accident model was developed by regression analysis in Changwon city. First, in order to analyze the effectiveness on traffic accidents by U-turn installation, the difference of mean of traffic accident number are measured between two groups which are composed by whether or not U-turn installation the groups by Mann-Whitney U test. The result of significance test showed that intergroup comparison on mean by accident types made difference except rear-end accident type and by accident locations exit section only showed difference in significance level at 4-legged intersections, so the accident number have more where the U-turn is permitted than not. Response measures about the number of accidents were classified by whether accidents occurred and accident model were constructed using binomial logistic regression analysis method. The developed models show that the variables of conflict traffic, number of opposing lane are adopted as independent variable for both intersections. The variables of longitudinal grade for 3-legged signalized intersection and number of crosswalk for 4-legged signalized intersection at which the U-turn is permitted is adopted as independent variable only. These study results suggest that U-turn would be permitted at the intersection where the number of opposing lane is more than 3.5 each, the longitudinal grade of opposing road is upward flow and there is need to establish the U-turn traffic sign at signalized intersections.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.471-478
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• 2003

In the Signalized Intersection, the capacity analysis is conducted with a large amount of input data such as road way, traffic and signal condition. but the level of service(LOS) is determined by delay estimated as a measure of effectiveness (MOE) based on this procedure. However, It is under the circumstances which are not considered for the errors caused by the uncertainty of input data in the field(the turing volumes, lane geometry, signal timing, grade of approach lane, percentage heavy vehicles, peak hour factor and arrival type etc.) as become the bases in the determination of the capacity and LOS. It includes the problem of reliability which is not verified for the capacity and LOS estimated. So, this study is to suggest the minimization of their influences by examining whether the uncertainty of input data such as the traffic volume, percentage of heavy vehicles and roadway geometry on the approach lane in the intersection under the study affects the capacity analysis and LOS determination.

• Journal of Korean Society of Transportation
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• v.21 no.3
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• pp.59-69
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• 2003

Signalized intersections are widely used in urban street network. However, it was reported that a roundabout is better than a signalized intersection in terms of delay when the approaching traffic volume for each bound is low. The objective of this study is to develop entry capacity models of roundabout and establish the warrant for signalized intersection based on the delay. The entry capacity of a roundabout is determined by the circulating traffic volume and the geometric design of the roundabout such as the diameter of central island, entry lane widths, and the circulating roadway width. The traffic and geometric characteristics of four roundabouts were collected and analyzed. The study reveals that; i)among the geometric features, the diameter of central island and the circulating roadway width influence the entry capacity, and ii)even though it is difficult to compare the models of each country due to different geometric features considered in the models, the models developed in this study show higher capacity than the models from Israel or Germany. These seem to be attributed to the facts that; i)the outside diameters of the roundabouts selected in this study are larger than in the other studies, and ii)the acceptable gap in Korea is smaller than that in the other countries. In order to compare the performances of round- about and signalized intersection, the performance of roundabouts was evaluated with the SIDRA. The simulation was conducted only for the roundabouts composed of single lane. According to the result of the analysis, it may be concluded that when the approaching traffic volume for each bound is lower than 600pcph, a roundabout is better than a signalized intersection in terms of its operational performance.

• Journal of Korean Society of Transportation
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• v.20 no.4
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• pp.73-82
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• 2002

The influence of bus stops near signalized intersections is one of the important factors which cannot be negligible in the analysis of the capacity of signalized intersections. Absence of consideration of bus bay can reduce capacity and increase the time that the stop of buses block other traveling vehicles. This influence is reflected by the bus blockage adjustment factor in KHCM, but the factor does not consider the course of each bus passing the intersection. Particularly, left turn buses have more influence on the capacity than the other buses and require the minimum length of the road for lane changes. All the existing criteria can apply only to arterial roads on which mostly traffic flows are continuous. And the criteria. which can determine the optimum location and the minimum distance between a signalized intersection and a bus bay, is not prepared and the related study is insufficient. Therefore, a theoretical formula is derived in this study being based on the theories which are avaliable to apply to the situation of signalized intersections.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.87-100
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• 1999

This study was focused on analyzing the headway of various types of trailer in Pusan city with the high heavy vehicle rate. Then Passenger Car Equivalent(PCE) was calibrated in order to identify the impact of trailers in the traffic flow at the signalized intersections. To fulfill this goal types of trailer were classified into five categories such as full trailer semi-trailer unloaded semi-trailer semi-trailer loaded with 20ft container and semi-trailer loaded with 40ft container and Passenger Car Equivalents were identified. the Results are as follows: 1) The PCE’s were 2.64, 1.51, 2.09, 2.16 and 2.23 respectively. 2) The saturation flow rate on the signalized intersection was lower than that on the multi-lane highway in the big city of Korea. 3) The start-up delay on the thru lane was similar to the average value in our country but the start-up delay on the left-turn lane was longer than the average value in our country by the impact of container Vehicles.

• International Journal of Highway Engineering
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• v.15 no.3
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• pp.159-167
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• 2013

PURPOSES: The purpose of this study is to develop an effectiveness analysis method of exclusive median bus lanes, which is necessary in order to improve operation efficiency of exclusive median bus lanes. METHODS : The operation characteristics of "signalized intersection including exclusive median bus lanes" and "normal signalized intersection" were investigated and the existing capacity analysis method was also reviewed to analyze the effectiveness of exclusive median bus lanes. Delay reduction of passengers using exclusive median bus lanes which can be considered as the benefit of exclusive median bus lanes and the number of people in buses were included in the proposed effectiveness analysis method. RESULTS : It was found that the proposed method expresses properly the effectiveness of exclusive median bus lanes through performing sensitivity analysis and analyzing with the real data of the number of people in buses and passenger cars. It was also found that the proposed method demonstrates the effectiveness that measure of effectiveness of signalized intersections is changed to "sec/person". CONCLUSIONS : It was concluded that the method is a proper effectiveness analysis method because it can reflect the benefit of passengers in buses.

• Journal of Korean Society of Transportation
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• v.9 no.2
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• pp.27-40
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• 1991

Delay is an widely-used tool for evaluating the operation of signalized intersections. This paper presents two mathematical models: a model converting stop delay into approach delay : and a model estimating delay at isolated signalized intersection. To develop the delay-conversion model, actual stop delay and approach delay experienced by individual vehicles were measured and then their relationship was formulated using ma-thematical procedure. the formula expressing the approach-delay to stop-delay ratio was a monotonously decreasing function of effective red time. New delay model was developed based on the following criteria; the fitness to measured delay for undersaturated traffic condition and the convergence to the deterministic overflow delay for oversaturated traffic condition. Performance of this model was better than those of other existing models based on the comparison study.