• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.25-32
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• 2010

This study deals with the roundabout by flare of entry and exit. The goal is to analyze the relative effectiveness of roundabout by flare of entry and exit. In pursuing the above, this study gives the particular attentions to comparing the performances using VISSIM software. The main results analyzed are as follows. First, the single and double roundabouts are analyzed to have LOS F in the case of total entering vehicles of 2,400pcph and 4,400pcph Second, the roundabouts by entry flare analyzed to have LOS F in the case of total entering vehicles of 2,800~3,200pcph and the roundabouts by entry and exit flare analyzed to have LOS F in the case of total entering vehicles of 3,200~3,600pcph. Finally, result of comparative analysis of roundabout and roundabout by flare of entry and exit, capacity of roundabout by flare of entry and exit are located between 1-lane roundabout and 2-lane roundabout. therefore it analyzed that roundabout by flare of entry and exit can be added to new type roundabout.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.77-83
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• 2011

This study deals with the effectiveness of roundabout. The goal is to comparatively analyze the operational effectiveness related to the conversion of rotary to roundabout in Korea. In pursuing the above, this study gives particular attentions to investigating the existing 20 rotaries and developing the networks of before-and-after improvement using VISSIM, and comparatively analyzing the effectiveness. The domestic rotaries were analyzed to need many improvements of geometric structure for the effective operation of roundabout. The main results are as follow. First, when the present condition of traffic volume were applied, the operational effect of rotary were evaluated to be better than roundabout, but the difference analyzed to be small. Second, the average delay per vehicle in the rotaries of urban area were analyzed to rapidly increase according to the growth of traffic volume. Finally, the average speed of roundabout were evaluated to be less (about 10km/h) than that of rotary, because the traffic volume of rural area were less than that of urban area.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.79-86
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• 2010

This study deals with the roundabout installed at the diamond interchange. The goal is to analyze the relative effectiveness of roundabout to signalized intersection. In pursuing the above, this study gives the particular attentions to comparing the performances using VISSIM software. The main results analyzed are as follows. First, the single and double roundabouts are analyzed to have the rapid change of delay in the case of total entering vehicles of more than 2,400pcph for directional rate 10:5:5, 2,800pcph for 10:8:2, and 4,400pcph for 10:2:8. Second, the roundabouts are evaluated to be more effective than signalized intersection in the case of total entering vehicles of less than 4,000pcph for directional rate 10:5:5, and 4,400pcph for 10:2:8. In the case of directional rate 10:8:2, double roundabout of total entering vehicles less than 5,600pcph is analyzed to be more effective than signalized intersection. Finally, the performance of double roundabout is analyzed to be very similar to that of single roundabout in the case of total entering vehicles less than 4,400pcph. However, the double roundabout is evaluated to be more effective than single in the case of total entering vehicles more than 4,400pcph.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.63-75
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• 2013

Roundabouts have been operated in Europe, America and Australia since the 1970s, and many relevant researches continually was carried out. Though many studies regarding roundabout have been recently conducted in korea, most of them have focused on its operational safety and efficiency. Moreover, roundabout design guideline did not define a clear criteria related to pedestrian in roundabout, but seldom investigate the influences of pedestrian on crosswalk. In this study, we seek ways to operate the pedestrian crosswalk signal on roundabout maximizing their operational effects in exceptional case such as rush hour or intersection near the special facilities. We proved that roundabout signal operation is effective under certain circumstances in according to the number of pedestrian, and suggested the optimal signal timing plan for signalized roundabouts. For pursuing the above, we conducted the simulation test using the VISSIM model. The results show that the operational effectiveness of signalized roundabout was evaluated to be better than non-signalized roundabout in specific pedestrian volume condition. In addition, those results are confirmed using simulation analysis conducted on the real roundabout.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.1-9
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• 2012

This study deals with the operation effectiveness of roundabout. The objective of this study was to analyze the operational effectiveness of roundabout based on the operation of pedestrian signal. For pursuing the above, VISSIM was as a traffic simulation program. this study gives particular attention to analyzing the 1,680 scenarios by operation of Pedestrian Signal(7 cases), roundabout type(2 cases), pedestrian volume(8 cases) and entering volume(15 cases). The main results analyzed are as follows. First, the operational effectiveness analyzed by 2 type of 4-legged 1-lane roundabout and 6 type of 4-legged 2-lane were evaluated to be better than that by the others type. Second, the average delay time analyzed by operation of pedestrian signal were evaluated to be less than that by unsignalized pedestrian crossing. Finally, the average delay time analyzed by pedestrian crossing were decreased 8.18% than that by staggered pedestrian crossing in 4-legged 1-lane. However, the average delay time analyzed by staggered pedestrian crossing were evaluated to be decreased 36.53% than that by pedestrian crossing in 4-legged 2-lane.

• Journal of Korean Society of Transportation
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• v.31 no.4
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• pp.3-17
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• 2013

The purpose of this study is to develop a traffic assignment model where the variable of signal intersection delay is taken into account in assigning traffic in large-scale network settings. Indeed, despite the fact that the majority of the increase in travel time or cost involving congested urban network or interrupted flow are accounted for by stop delays or congested delays at signal intersections, the existing traffic assignment models did not reflect this. The traffic assignment model considering intersection delays presented in this study was built based on the existing traffic assignment models, which were added to by the analysis technique for the computation of intersection delay provided in Korea Highway Capacity Manual. We can conclude that a multiple variety of simulation tests prove that this model can be applied to real network settings. Accordingly, this model shows the possibility of utilizing a model considering intersection delay for traffic policy decisions through analysis of effects of changes in traffic facilities on large urban areas.

• Proceedings of the KOR-KST Conference
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• 1998.10a
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• pp.105-114
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• 1998

Roundabout의 교통운영 특성에 대한 연구에서는 5거리 도로체계의 올바른 분석과 로타리에서 일어나는 진입로의 교통량, 회전교통량, 속도, 거부gap, 수락gap, 추종간격, 기하구조등을 조사 분석하여 수락간격 모형을 바탕으로 비신호교차로의 용량산정과 지체시간을 산정하기 위한 모형을 구축하는데 있다.

• Journal of Korean Society of Transportation
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• v.20 no.1
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• pp.77-90
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• 2002

Network expansion has been an inevitable method for most traffic equilibrium assignments to consider intersection movements such as intersection delays. The drawback of network expansion is that because it dramatically increases network sizes to emulate possible directional movements as corresponding links, not only is complexities for building network amplified, but computational performance is shrunk. This paper Proposes a new variational inequality formulation for a user-optimal traffic equilibrium assignment model to explicitly consider directional delays without building expanded network structures. In the formulation, directional delay functions are directly embedded into the objective function, thus any modification of networks is not required. By applying a vine-based shortest Path algorithm into the diagonalization algorithm to solve the problem, it is additionally demonstrated that various loop-related movements such as U-Turn, P-Turn, etc., which are frequently witnessed near urban intersections, can also be imitated by blocking some turning movements of intersections. The proposed formulation expects to augment computational performance through reduction of network-building complexities.

• Journal of Korean Society of Transportation
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• v.29 no.5
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• pp.79-89
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• 2011

Though many studies regarding roundabout have been recently conducted, most of them have focused on operational aspect. Moreover, majority of the previous researches analyzes operational effects of single roundabout, but seldom investigate the effects of multi-roundabouts constructed on road networks. In this study, we seek ways to construct multiple roundabouts on road network maximizing their operational effects. The analysis investigate influence of both adjacent signalized and unsignalized intersections as well as influence of the distance from those intersections to roundabouts. The results show that the optimal distance between two adjacent intersections were calculated to be 150m, and any two intersections located within 150m apart influence each other thus imposing operational restrictions on each other. In addition, those results are confirmed using simulation analysis conducted on the real urban network in Nonheon regional area, Incheon City.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.5
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• pp.45-58
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• 2021

It is generally known that a two-lane roundabout has some problems in safety such as increasing conflicts, typically merging and diverging conflicts and conflicts between entering traffic and exiting as well as turning traffic. To solve these problems, a turbo-roundabout had been developed and has successfully brought safer and more efficient operation in other countries. In this study, micro simulations using VISSIM were conducted to investigate the maximum value of service traffic volume. It was found that operation of turbo-roundabouts was influenced by traffic volume for each turning traffic, and the maximum values of traffic volume were values between 2,400 and 2,800 vehicles per hour as rates of traffic volume for each turning traffic. Typically, turbo-roundabouts have limited to operate in conditions with more than 30% for left-turning traffic volume.