• Proceedings of the KOR-KST Conference
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• 1996.02a
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• pp.59-86
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• 1996

Current methods for evaluating unsignalized intersections, and estimating level-of-service (LOS) is determined from efficiency-based criteria such as little or no delay to very long delays. At present, similar procedures to evaluate intersections using safety-based criteria do not exist. The improvement of sight distances at intersections is the most effective way of improving intersection safety. However, a set of procedures is necessary to account for the limitations in current methodology. Such an approach would build upon such methods, but also account for: deficiencies in the current deterministic solution for the determination of intersection sight distances; opportunity for an accident and severity of an accident; and cost-effectiveness of attaining various levels of sight distances. In this research, a model that estimates the degree of safety at two-way stop-controlled intersections is described. Only crossing maneuvers are considered in this study because accidents caused by the crossing maneuvers are the dominate type among intersection accidents. Monte Carlo methods are used to estimate the hazard at an intersection as a function of roadway features and traffic conditions. Driver`s minimum gap acceptance in the crossing vehicles and headway distribution on the major road are used in the crossing vehicles and headway distribution on the major road are used in the model to simulate the real intersectional maneuvers. Other random variables addressed in the model are: traffic speeds; preception-reaction times of both drivers in the crossing vehicles and drivers in oncoming vehicles on the major road; and vehicles on the major roads. The developed model produces the total number of conflicts per year per vehicle and total potential kinetic energy per year per vehicle dissipated during conflicts as measurements of safety at intersections. Based on the results from the developed simulation model, desirable sight distances for various speeds were determined as 350 feet, 450 feet and 550 feet for 40 mph, 50 mph and 60 mph prevailing speed on the major road, respectively. These values are seven to eight percent less than those values recommended by AASHTO. A safety based level-of-service (LOS) is also developed using the results of the simulation model. When the total number of conflicts per vehicle is less than 0.05 at an intersection, the LOS of the intersection is `A' and when the total number of conflicts per vehicle is larger than 0.25 at an intersection, the LOS is `F'. Similarly, when the total hazard per vehicle is less than 350, 000 1b-ft2/sec2, the LOS is `F'. Once evaluation of the current safety at the intersection is complete, a sensitivity analysis can be done by changing one or more input parameters. This will estimate the benefit in terms of time and budget of hazard reduction based upon improving geometric and traffic characteristics at the intersection. This method will also enable traffic engineers in local governments to generate a priority list of intersection improvement projects.

• 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 the Korean Association of Geographic Information Studies
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• v.12 no.3
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• pp.45-55
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• 2009

This study was intended to increase efficiency of traffic flow management on intersection. The result suggested to establish a left-turn at own risk lane to increase efficiency of traffic flow on intersection. The scope of the research was to investigate the geometric structure of a signal-controlled intersection, traffic volume(density) with respect to directions and traffic signal display, and to select a signalling intersection into which a car waiting for a traffic signal enters by adjusting the display sequence of traffic signal. The delay with respect to directions and for the whole intersection was compared for the current situation and an improvement plan. Using TSIS, a traffic analysis package, the traffic situation on an intersection was investigated. Based on the simulation result for Seok-Jeon intersection in Ma-San selected from the field investigation of intersections to which an improvement plans would be applicable, the waiting time in the direction without a entering traffic signal was decreased to be 78.6 seconds per car and that of the direction expecting the increase of waiting time was increased by 4 seconds per car only. It was confirmed that the waiting time for the whole intersection was improved.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.11
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• pp.1344-1352
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• 1999

본 논문에서는 두 단순 다각형의 교차 영역을 구하는 문제를 재구성메쉬(RMESH) 상에서 상수 시간에 해결하는 두 개의 알고리즘을 제시한다. 먼저, 두 다각형이 모두 볼록 다각형일 때, N$\times$N RMESH에서 상수 시간에 교차 영역을 구하는 알고리즘을 제시한다, 여기서 N은 두 다각형의 정점의 개수의 합이다. 그리고, 두 일반적인 단순 다각형의 교차 영역을 구하는 문제에 대해서 (N+T)$\times$(N+T)2 RMESH에서 수행되는 상수 시간 알고리즘을 제시한다, 여기서 T는 최악의 경우 두 다각형의 경계선 상의 교차점의 개수로서 두 다각형의 정점의 개수가 각각 n과 m일 때 n.m에 해당한다. 두 다각형 중 하나가 볼록 다각형인 경우는 T = 2.max{n, m}이다. 이 알고리즘은 두 다각형의 모든 교차 영역 조각들을 구한 후 RMESH의 0번째 열에 차례로 배치해 준다. Abstract In this paper, we consider two constant time algorithms for polygon intersection problems on a reconfigurable mesh(in short, RMESH). First, we present a constant time algorithm for computing the intersection of two convex polygons on an N$\times$N RMESH, where N is the total number of vertices in both polygons. Second, we present a constant time algorithm for computing the intersection of two simple polygons on an (N+T)$\times$(N+T)2 RMESH, where T is the worstcase number of intersection points between the boundaries of them. T = n m, where n and m are the numbers of vertices of two polygons respectively. If either of them is convex, then T = 2 max{n,m}. The algorithm computes the intersection of them, and then arranges each intersection component onto the 0-th column of the mesh.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.27-35
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• 2009

The roundabout was developed in the United Kingdom to rectify problems associated with these traffic circles. In 1966, the United Kingdom adopted a mandatory "give-way" rule at alt circular intersections, which required entering traffic to give way, or yield, to circulating traffic. However, the roundabout used in United States or Europe do not common use in Korea. The purposes of the study is to comparatively analyze the effectiveness of roundabout. In pursuing the above, this study designs the scenarios which can reflect the directional traffic volumes, and analyzes the average control delay of roundabout and 4-leg signalized intersection by SIDRA. The main study results are as follows. First, when the entering traffic volume are less than 2,000pcph, the single-lane roundabout is analyzed to be more effective than 4-leg signalized intersection. Second, when the entering traffic volume are less than 3,200pcph, the double-lane roundabout is evaluated to be more effective than 4-leg signalized intersection. Third, which is installed left and right turn lane at intersection, area for the roundabout is analyzed to be less than that for general intersection area.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.91-98
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• 2015

PURPOSES : Although signalized intersections have been considered the best way to control traffic volume in urban areas for several decades, roundabouts are currently being discussed as an alternative way to control traffic volume, especially when traffic is light. Because a roundabout's efficiency depends on the load geometry as well as the traffic volume, design guidelines for roundabouts are recommended only if the incoming traffic volume is very low. It is rare to substitute a roundabout for an existing signalized intersection in urban areas. This study aims to estimate the benefits from the transformation of an existing signalized intersection into a roundabout in an urban area. When there is a more moderate volume of traffic, roundabouts can be effectively used by optimizing signals located at an approaching roadway. METHODS : The methodologies of this paper are as follows: First, a signalized intersection was analyzed to determine the traffic characteristics. Second, the signalized intersection was transformed into a roundabout using VISSIM microscopic traffic simulation. Then, we estimated and analyzed the effects and the performance of the roundabout. In addition, we adjusted a method to improve the benefits of the transformation via the optimization of signals located at an approaching road to control the incoming traffic volume. RESULTS : The results of this research are as follows: The signal-optimized roundabout improved delays compared with the signalized intersection during the morning peak hour, non-peak hour, and evening peak hour by 1.78%, 12.45%, and 12.72%, respectively. CONCLUSIONS : According to the simulation results of each scenarios, the signal-optimized roundabout had less delay time than the signalized intersection. If optimized signal control algorithms are installed in roundabouts in the future, this will lead to more efficient traffic management.

• Journal of KIISE
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• v.43 no.4
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• pp.404-410
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• 2016

Automated road map generation poses significant research challenges since GPS-based navigation systems prevail in most general vehicles. This paper proposes an automated detecting method for intersection points using GPS vehicle trajectory data without any background digital map information. The proposed method exploits the fact that the trajectories are generally split into several branches at an intersection point. One problem in previous work on this intersection detecting is that those approaches require stopping points and direction changes for every testing vehicle. However our approach does not require such complex auxiliary information for intersection detecting. Our method is based on partial trajectory matching among trajectories since a set of incoming trajectories split other trajectory cluster branches at the intersection point. We tested our method on a real GPS data set with 1266 vehicles in Gangnam District, Seoul. Our experiment showed that the proposed method works well at some bigger intersection points in Gangnam. Our system scored 75% sensitivity and 78% specificity according to the test data. We believe that more GPS trajectory data would make our system more reliable and applicable in a practice.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.213-220
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• 2011

Objective: The aim of this study was to investigate middle-aged drivers' driving performance and heart-rate as the behavior and physiological changes due to intersection types in left-turn situation. Background: In Korea, the drivers were aged 40~50s are most plentiful. In addition, the intersection traffic accidents are increasing every year. However, the researches for middle-aged drivers and intersection environments have been little. Method: In this study, three kinds of left-turning intersection types(T1, T2, T3) was used as the within-subject independent variables, three age groups(young, middle-aged, elderly) was used as the between-subject independent variables. Also, passing time, approaching velocity, speed and steering variations and heart-rate were used as dependent variables. Results: Overall, middle-aged drivers' driving behaviors were similar to those of the younger drivers. At the T2 intersection type, however, the approaching velocity of middle-aged drivers was similar to younger drivers, whereas the passing time of middle-aged drivers was similar to elderly drivers. Conclusion: These results could be interpreted that a transition driving behavior of middle-aged drivers in terms of age would be appeared on the T2 intersection type. Application: The results might help to understand the characteristics of driving behavior for middle-aged drivers.

• 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.

• 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.