• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5D
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• pp.563-570
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• 2009

This study is aimed to analyze the overall effects of the additional delay caused by the vehicle in front of the queue, at the signal, to the total delay estimation. To estimate the average vehicle delay at the signalized intersection, as survey of the queue length at the intersection and traffic counts were conducted. As a result of this analysis, all of the three delay estimation methods turned out to be similar in that the estimation of the average delay for the test vehicle was less than 60 sec/vehicle. However, the average delay time for the vehicle in front of the queue only, was estimated at 60-70 sec/vehicle which is similar to the average delay of the test vehicle.

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.83-91
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• 2012

This study deals with the operational efficiency of roundabout. The roundabouts generally have such the merits as high capacity, delay reduction, safety improvement, and others. Circular intersection can be divided into the rotary and roundabout according to travelling priority. The objective of this study is to comparatively analyze the operational efficiency of rotary and roundabout by scenario. In pursuing the above, this study gives the particular attentions to developing 256 scenarios according to the directional and entering traffic volume and analyzing the delay using VISSIM. The main results are as follows. First, the average delay of rotary was analyzed to be 1.56-8.74 times of roundabout. Second, the operational efficiencies of rotary and roundabout were analyzed to be better in the case of bigger differences in the traffic volumes between the main and minor roads. Third, the average delay of the 4-legged was evaluated to be 1.77-11.70 times of 3-legged intersection. Finally, 2-lane intersection (3-legged & 4-legged) was analyzed to be 2.02-2.23 times of 1-lane intersection.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.42-52
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• 2017

This was a study on the ultimate effect and characteristics of introducing a roundabout through a review of literature on the subject of roundabout. In order to examine an effect produced when roundabout is substituted for ordinary signal-controlled intersection operated at Daego Five-way Intersection and Seongmo Five-way Intersection located in Junggu, Daejeon Metropolitan City, site to be studied, the produced effect was analyzed through comparison between before and after introducing roundabouts in series at Daego Five-way Intersection and Seongmo Five-way Intersection by using microscopic traffic simulation program VISSIM widely used for analyzing an effect of roundabout based on a survey of geometric structure, traffic volume and signal interval on the site. As mentioned above, when Daego Five-way Intersection and Seongmo Five-way Intersection was changed to roundabout, a positive effect was produced on average speed and delay time in comparison with the existing status. It is possible to expect that roundabout can be more efficiently operated when 2 places on the site are changed to double roundabout than when separately changed to roundabouts.

• Journal of Korea Water Resources Association
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• v.53 no.7
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• pp.533-543
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• 2020

In order to provide information for proper management of groundwater resources, it is necessary to estimate the rise time of groundwater level by calculating the delay time between the time series of precipitation and groundwater level and to understand the characteristics of groundwater level variation. In this study, total delay time (TDT) and cross correlation coefficient between the moving averaged precipitation generated by using the moving average method to take into account the preceding precipitation and the groundwater level were calculated and analyzed for the nine groundwater level monitoring wells in the Pyoseon watershed in the southeast of Jeju Island. As a result, when the moving averaged precipitation was used, the correlation with the groundwater level was higher in all monitoring wells than in the case of using the raw precipitation, so that it was possible to more clearly estimate the delay time between precipitation and groundwater level. When using the moving averaged precipitation, it had cross correlation coefficients of up to 0.57 ~ 0.58 with the time series data of the groundwater level, and had a relatively high correlation when considering the preceding precipitation of about 24 days on average. The TDT was about 32 days on average, and it was confirmed that the consideration of preceding precipitation plays an important role in estimating the TDT because the days of moving averaged precipitation greatly influences the calculation of the TDT. In addition, through the use of moving averaged precipitation, we found an error in estimating the TDT due to the use of raw precipitation. Through the method of estimating the TDT used in this study and the use of the R code for estimating the TDT presented in the appendix of this paper, it will be possible to estimate the TDT for other regions in the future relatively easily.

• Journal of Korean Society of Transportation
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• v.15 no.2
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• pp.105-122
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• 1997

본 연구는 대각선 횡단보도의 정량적 설치기준을 정립하기 위하여 이상적인 조건에서의 교차로 각현시별 임계차선 교통량의 합($\sum_i$ CVi)을 600~1,800대로 변화를 주어 실험적 시뮬레이션 방법을 적용하였다. TRANSTY-7F 모형을 이용한 교차로 평균차량 지체도와 본 연구에서 정립한 보행지체모형을 이용한 교차로 평균 보행지체도와의 관계를 변수로 하여 대각선 횡단보도의 정량적 설치기준을 각 조건별로 산정한 결과 다음과 같은 결론이 도출되었다. 첫째, 동시신호시 교통량과 보행량의 비율이 1:1일 경우 대각횡단비율 20~40%에서는 $\sum_i$ CVi=1,050~1,150대 이하에서 대각선 횡단보도를 설치시 지체도 감소에 대한 편익을 얻을 수 있다. 둘째, 동시신호시 교통량과 보행량의 비율이 1:2일 경우 대각횡단비율 20~40%에서는 $\sum_i$ CVi=1,150~1,200대 이하에서 대각선 횡단보도를 설치시 지체도 감소에 대한 편익을 얻을 수 있다. 셋째, 선행 좌회전신호시 교통량과 보행량의 비율이 1:1일 경우 대각횡단비율 20~40%에서는 $\sum_i$ CVi=600~750대 이하에서 대각선 횡단보도를 설치시 지체도 감소에 대한 편익을 얻을 수 있다. 넷째, 선행 좌회전신호시 교통량과 보행량의 비율이 1:2일 겨우 대각횡단비율 20~40%에서는 $\sum_i$ CVi=750~900대 이하에서 대각선 횡단보도를 설치시 지체도 감소에 대한 편익을 얻을 수 있다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.1
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• pp.83-93
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• 2020

The time delay is used as a major indicator of the level of traffic congestion on traffic crossroads. For this purpose, the Daechi Station intersection where traffic congestion occurs and the Yeongdong 5 Bridge intersection where the traffic condition is relatively good, and the average lag time based on the field survey with the lag time calculated various simulation programs. comparison of the average control delay of the field survey data the signal intersection analysis model the KHCS Dechi intersection 7.7 second / vehicle Young dong 5 bridge intersection 7.9 second / vehiclehe VISSIM showed a difference Dechi intersection 21.1 second / vehicle and Young dong 5 bridge intersection 8.1 second / vehiclehe T7F showed a difference Dechi intersection 3.3 second / vehicle and Young dong 5 bridge intersection 9.3 second / vehicle. Analyzing the same intersection proved that the results differed from one simulation model to another.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.149-159
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• 2002

The performance of two single-barrier three-phase control systems at diamond interchanges was evaluated for various traffic conditions. To emulate the actuated signal control, hardware-in-the-loop system combined with CORSIM simulation program was used. Two performance measures, average delay and total stops, were used for the evaluation process. Results showed that the two three-phase systems gave similar performance in terms of average delay, but not stops. The delay performance of each phasing system was generally dependent on the traffic pattern and ramp spacing. However, there was a distinct movement preference for each phasing system. The total stops decreased as the spacing increased, and it was the most sensitive variable that can differentiate between the two three-phase systems. It was also shown that the hardware-in-the-loop control could be a good method to overcome the limitations of current simulation technology.

• Water for future
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• v.28 no.4
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• pp.155-169
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• 1995

Three types of methods are used to determine the lag time which is an important parameter in estimating the geomorphological instantaneous unit hydrograph (GIUH) and their results are anlyzed hydrologically in this study. The first method uses only the average velocity and second one uses the combination of the stream length and the average velocity. The third method employs the relationship between watershed area and lag time obtained from the empirical coefficients of Boyd and Singh. To verify the applicabilities of such methods to the actual river basin, the obtained lag times were tested by using the observed data. The results showed that the first method was applicable to small watershed area but not to larger area. The several other hydrologic characteristics beside the watershed area should be considered for the third method because the accuracy of the lag time was not good. Finally, the second method gave the most similar simulation results and the best agreements to the observed runoff data than any other method.

• Journal of Korean Society of Transportation
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• v.35 no.5
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• pp.385-395
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• 2017

This study deals with the small-scale roundabout. The purpose of this study is to analyze the average delay of vehicle in roundabout, and suggest the efficient planning and design standard. In pursuing the above, this study gives particular attentions to analyzing the average delay time according to the inscribed circle diameter, speed of circulatory roadway lane and traffic volume. The operational efficiencies of 96 scenarios (3 sizes of inscribed circle diameter ${\times}$ 4 types of circulatory roadway speed ${\times}$ traffic volume) are analyzed using VISSIM (Verkehr In $St{\ddot{a}}dten$-SIMulationsmodell). The main results are as follows. First, the optimal design speed of small-scale roundabout are derived from the above scenario analysis. Second, the traffic volume of LOS D is estimated to be 2,180-2,740pcph. Third, the traffic volume of LOS F that is required to improve is above 2.780pcph. The results might be expected to give some implications to providing the countermeasures for the operational efficiency of roundabout.

• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.75-84
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• 2010

Controlled traffic intersection is critical point in terms of transportation network performance, where the most of traffic congestion arises. One of the most important and favorable measure of effectiveness in the signal controlled intersection is approach delay. Although lots of efforts to develop traffic delay estimation models have been made throughout the years, most of them were focusing on homogeneous traffic flow. The purpose of this research is to develop a traffic delay estimation model for traffic flow mixed with bus based on the horizontal shockwave theory. Traffic simulation is performed to test the adaptation level of the model in generic environment. The result shows that the delay increases with increasing bus traffic. Overall model accuracy comparing simulation result is acceptable, that shows the error range around 10 percent.