• Journal of Korean Society of Transportation
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• v.31 no.6
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• pp.43-52
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• 2013

A roundabout is a form of circular intersection in which traffic travels counterclockwise around a central island and in which entering traffic must yield to circulating traffic. It has been known that a roundabout provides substantially better operational and safety characteristics than other intersections including rotaries. Recently, a roundabout has started to be constructed due to its efficiency, safety, and other advantages of a roundabout comparing other intersections in Korea. However, there has been no guideline to be used to decide appropriate intersection types considering given conditions of the intersections. To solve this problem, the guideline with traffic volume to choose the suitable intersection types was developed based on analysis results using the SIDRA software which is generally used to analyze operational effects of roundabouts. It was found that a roundabout is more efficient than signalized intersection when the traffic volume is between 125 and 450 veh/h on one lane road and roundabout is not recommended when there are more than 30% left turn traffic. The optimal traffic volume provided in this research will be usefully used in planing and designing roundabouts in Korea.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.47-56
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• 2008

Generally, accident exposure at intersections is relatively higher than that at roadway segments due to more possibility of merging, diverging, turning, crossing, and weaving maneuver. Furthermore, the traffic accident rate at intersections has been rapidly increasing since 1990's. Since there is more opportunity of conflict at unsignalized intersection, frequency and severity of traffic accident are more severe than signalized intersections. The purpose of the study is to analyze factors causing vehicle crashes and provide intersection design guidelines to improve intersection safety. For this study, vehicle to vehicle crash data of 116 rural 3 legs unsignalized were collected and field surveys were conducted for traffic and geometric conditions. Ordered probit models were developed to analyze the severity of crashes. It was found that weather, obstacles in minor roadsides, presence of major exclusive right lane, presence of major road crosswalk, difference between posted speed of major road and minor road, land-use around intersections, shoulder width of major road, ADT of major road are significant factors for intersection safety.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.124-136
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• 2019

Autonomous driving at intersections requires assistance by exchanging traffic information between traffic objects due to the intersection of various vehicles and complicated driving environment. For this reason, traffic information exchange between adjacent intersections is required, but the node ID representing the intersection in the Korean standard node link system have limitations in updating intersections and identifying location information of intersections through IDs due to the configuration system including serial numbers. In this paper, we designed a coordinate-based intersection ID configuration system created by processing and merging two-dimensional coordinates of intersections to include location information in the intersection ID. In order to verify the applicability of the proposed intersection ID, we applied a new intersection ID to domestic intersections and confirmed that there are no duplicate values. Coordinate-based intersection ID reduces data size by 60% compared to existing node ID, and enables spatial queries such as searching for nearby intersections and extracting intersections in specific areas in the form of boxes without GIS tools. Therefore, coordinate-based intersection ID is expected to be more scalable and utilized than existing node ID.

• 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.27 no.2
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• pp.107-115
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• 2009

Traffic islands were introduced for drivers and pedestrians to use the road in a safe and orderly way and were also a specified zone between traffic lanes to divide conflicting traffic flows and to provide pedestrian refuge. However, existing research and relevant standards described its purpose and effects only but not a safety standard to decide whether the traffic island warranted. This study was to introduce a parameter which had a high relationship with accidents by analyzing road and traffic conditions and traffic accident data at urban intersections. Based on the relationship between the parameter and the traffic accidents at the intersection, a pedestrian accident probability model was made by using a logit model. In addition, the study reviewed a pedestrian accident probability corresponding to traffic volume and size of the intersection during design of the intersection and then suggested the effectiveness of the traffic island in terms of traffic safety. In conclusion, when a large-scale intersection has significant traffic volumes, a high probability of traffic island-induced pedestrian accidents appears, while in the case of small volumes, the probability is low. Targeted design and operations of a traffic islands is necessary, because its introduction itself does not enhance pedestrian safety in all cases at all intersections. This study can be a useful reference for further development to set up a scheme of the traffic islands in terms of traffic safety.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.8
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• pp.544-554
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• 2014

In this paper, we introduce a cyber-physical intersection systems (CPIS) which intimately interconnects roadside units (RSU) located at intersection, on-board units (OBU) of moving vehicles, and smartphone apps. Based on the architecture of CPIS, we also present a green light optimal speed advisory based on the reference mobility models (GLOSA-RMM) to reduce intersection stopping time (IST) and fuel consumption. Based on several reference mobility models, the GLOSA-RMM determines the appropriate speed advisory by taking into account the current mobility and the intersection traffic light status, and then provides screen/voice GLOSA instructions to minimize the driver's distraction. We show that the GLOSA-RMM can reduce both the IST and the fuel consumption through the numerical results obtained from the prototype of the CPIS consisting of the OBU, the RSU and the smartphone app.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.301-303
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• 2007

본 논문은 RFID를 이용한 효율적인 교통신호 체계를 구축하기 위해서 연구했다. 이 시스템은 4차선의 주차로 와 2차선의 소방로로 이루어진 교차로 에서 주차로의 교통량이 많을 경우, 차로에서는 녹색불이 지속되어 교통의 흐름을 원활하게 해주며, 소방로에서 차량이 일정량 증가하게 되면, 주차로의 선호 등이 적색등으로 바꾸어 소방로의 차량이 소통되도록 하는 지능형 교통체계시스템용 설계하였다. 본 시스템의 구성을 위해서 RFID 태그를 차량에 설치하고, 리더기를 도로에 설치하여 차량의 유무를 판별할 수 있도록 하였다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.839-842
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• 2008

Construction VE is the system introduced in order to reduce the life cycle cost and promote the performance of construction facilities, used in architecture and civil construction since apply to construction over 10 billion from december 2005. But yet it is short of VE specialist and it is not a purpose in maximization of value creation through VE but strong better awareness of tool for budget reduce. This study tries to contribute to qualitative advance of design VE by analyze substantial degree of VE Procedure and VE result by Job Plan used widely in domestic an object design VE competition case to crossroad.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.33-41
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• 2010

It is stated in the highway geometric design guide that expressway interchange types should be selected considering a set of input variables including travel demand, topography, construction cost and interchange spacing. However, this selection method has a problem of providing different interchange types even for the same input variables depending upon different applications of engineers discretion. A procedure that produces consistent results is necessary and this paper presents the development of an efficient and reliable procedure based on the quantification of road user costs and construction costs on interchanges. To develop this procedure, a survey of existing expressway interchange types in South Korea was made and 10 basic interchange types and 52 supplementary interchange types were identified. To relate road user costs and construction costs to these interchange types, this research uses two method. First, interchange types were expressed by a set of ramp configurations. Second, road user benefits and construction costs associated with these different interchange types were formulated based on the current national guide of the expressway economical analysis. As a result, it was proved that an interchange type to provide minimum costs could be selected consistently and this research result should be useful for future expressway geometric designs.

• 한국도로학회:학술대회논문집
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• 2008.10a
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• pp.307-320
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• 2008