• Journal of Korean Society of Transportation
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• v.31 no.1
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• pp.57-64
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• 2013

Recently, bicycle accidents have increased with the ever-increasing number of cyclists. Bicycle accidents occurred frequently in intersections, and the perpendicular collision between a right-turning car and a crossing bicycle was the most prevalent accident type. In particular, the collision was caused by motorists' carelessness. In other words, the accident-involved motorists did not pay sufficient attention to a bicycle crossing behind them. Another cause was a cyclist's higher speed than pedestrians. This paper evaluated the potential risk of the collision between right-turning cars and crossing bicycles based on simulation experiments, with motorists' speed and carelessness focused on. Consequently, it was found that to reduce the potential risk of the collisions a motorist should slow down and pay more attention to the rear sight by turning his/her head.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.2
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• pp.165-171
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• 2013

WAVE(Wireless Access in Vehicular Environments) is a representative V2V communication protocol and its standards of MAC and PHY parts except for security were published. In order to control traffic flow and ensure driver's safety using V2V communication, various projects are conducting. In particular, safety application has been researched. Therefore, in this paper, we designed the safety application algorithm, which informs a driver of the dangerous status when driver tries to turn left in an intersection and we also implemented the algorithm. Proposed algorithm configures a model for a host vehicle and a vehicle coming in opposite lane and in case that there is collision hazard it provides warning message to driver by using HMI. In order to evaluate the proposed algorithm's performance, we configured the test bed using test vehicles and we tested the algorithm on proving ground with the composed test scenarios. As test results, our system showed excellent performance. If the infrastructures for V2I communications are constructed, we will optimize our system more precisely and stably.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.2
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• pp.90-96
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• 2021

In this study, the method of determining the state of grid points in the adaptable surface particle method based on grid system developed as a free-surface tracing method was improved. The adaptable surface particle method is a method of determining the state of the grid point according to the shape of the free-surface and obtaining the intersection of the given free-surface and grid line where the state of the grid point changes. It is difficult to determine the state of grid points in the event of rapid flow, such as collision or separation of free-surfaces, and this study suggests a method for determining the state of current grid points using the state of surrounding grid points where the state of grid point are known. A grid layer value was assigned sequentially to a grid away from the free-surface, centering on the boundary cell where the free-surface exists, to identify the connection information that the grid was separated from the free-surface, and to determine the state of the grid point sequentially from a grid away from the free-surface to a grid close to the free-surface. To verify the improved method, a numerical analysis was made on the problem of dam break in which a sudden collision of free-surface occurred and the results were compared, and the results were relatively reasonable.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.4
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• pp.14-34
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• 2023

The purpose of this study was to calculate the appropriate yellow-signal time for intersections, to find out the relationship between the approach speed and intersection width when calculating the time, and to secure safety by minimizing conflicts and dilemma sections in intersections that change according to the signal operation. For this purpose, 6,824 data points from 5 intersections were collected and analyzed. The main results of the study are as follows. First, the approach speed of individual vehicles in different lanes was analyzed, and the width of an intersection was defined by considering the conflict in each direction. Second, we developed a multiple regression model based on the approach speed and conflict points, which compensated for the problems of an existing formula. Third, a standard table is presented for applying the appropriate yellow-signal time according to the approach speed and intersection width based on a development formula. A method is also presented to determine the safety of the length of the dilemma according to the change in the yellow-light time by presenting a calculation table that can cross-analyze the yellow-signal time and a dilemma section using the relationship.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.128-141
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• 2018

In this paper, a methodology to analyze the potential safe benefit of six cooperative driver assistance systems via V2V (vehicle-to-vehicle) communications is proposed. Although it is quite necessary to assess social impact with respect to new safety technologies for cooperative vehicles with V2V communications, there are few studies in Korea to predict the quantitative safety benefit analysis. In this study, traffic accident scenarios are classified based on traffic fatality between passenger cars. The sequential collision type is classified for a multiple pile-up with respect to collision direction such as forward, side, head-on collisions. Then movement of surrounding vehicle is considered for the scenario classification. Next, the cooperative driver assistance systems such as forward collision warning, blind spot detection, and intersection movement assistance are related with the corresponding accident scenarios. Finally, it is summarized how much traffic fatality may be reduced potentially due to the V2V communication based safety services.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.563-566
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• 2006

In this paper, we studied about AGVs modeling and material handling automation simulation using a virtual AGV. The proposed virtual AGV model that operates independently each other is based on a real AGV. Continuous straight-line and workstation model using vector drawing method that could easily, rapidly work system modeling are suggested. Centralized traffic control, which could collision avoidance in intersection and should not stop AGV as possible, and algorithm for detour routing which performs when another AGV is working in pre-routed path are proposed. The traffic control and the algorithm have been proved efficiently by simulation.

• Journal of the Ergonomics Society of Korea
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• v.35 no.3
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• pp.135-142
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• 2016

Objective: Objective of this study is to provide characteristics of injury frequency and severity by driving condition in large truck-related traffic collisions. Background: Traffic accidents involving large trucks draw a lot of attention in accident prevention and management policies since they bring about severe human and financial damages. Method: In order to identify the major risk factors of accidents by driving condition, 255 recognized traffic accidents by large truck drivers were analyzed in terms of time of the day, road type, and shape of the road. Results: The driving conditions in the results are represented by the following form of combination, "Road Type (Non-expressway or Express) - Shape of Roads (Straight, Curved, Downhill, or Intersection) - Time of Accidents (Day or Night)". In the analysis of injury frequency, Non-expressway-Straight-Day condition was the most frequent one. Meanwhile, Expressway-Curved-Day, Non-expressway-Curved-Night and Non-expressway-Intersection-Night were evaluated as high level in view of injury severity. Also, Expressway-Straight-Night is the driving condition that is the highest in risk among the conditions that have to be managed as grade "High". Non-expressway-Straight-Night, Non-expressway-Downhill-Day, and Non-expressway-Curved-Day are also categorized as grade "High". Conclusion and Application: Safety managers in the fields require basic information on accident prevention that can be easily understood. The research findings will serve as a practical guideline for establishing preventive measures for traffic accidents.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.11
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• pp.1102-1107
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• 2009

An ultrasonic sensor has been widely used as a range sensor for its low cost and capability of detecting some obstacles, such as glasses and black surfaces, which are not well detected by a laser scanner and an IR sensor. Although low-cost sensors are preferred for practical service robots, they suffer from the inaccurate and insufficient range information. This paper proposes a novel approach to obstacle avoidance using low-cost anisotropic ultrasonic sensors with wide beam angle. In this paper, obstacles can be detected by the proposed sensor configuration which consists of one transmitter and three receivers. Because even wide obstacles are represented by a point, which corresponds to the intersection of range data from each receiver of the anisotropic sensor, a robot cannot avoid wide obstacles successfully. This paper exploits the probabilistic mapping technique to avoid collision with various types of obstacles. The experimental results show that the proposed method can robustly avoid obstacles in most indoor environments.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.499-505
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• 2004

In this paper, we studied about AGVs modeling and material handling automation simulation using a virtual AGV. The proposed virtual AGV model that operates independently each other is based on a real AGV. Continuous straight-line and workstation model using vector drawing method that could easily, rapidly work system modeling are suggested. Centralized traffic control, which could collision avoidance in intersection and should not stop AGV as possible, and algorithm for detour routing which performs when another AGV is working in pre-routed path are proposed. The traffic control and the algorithm have been proved efficience by simulation.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.135-146
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• 2013

PURPOSES : This study aimed to analyze the impact the operation of pre-signals at 4-leg signalized intersections and present primary environmental factors of roads that need to be considered in the installation of pre-signals. METHODS : Shift of proportions safety effectiveness evaluation method which assesses shifts in proportions of target collision types to determine safety effectiveness was applied to analyze traffic crash by types. Also, Empirical Bayes before/after safety effectiveness evaluation method was adapted to analyze the impact pre-signal installation. Negative binomial regression was conducted to determine SPF(safety performance function). RESULTS : Pre-signals are effective in reducing the number of head on, right angle and sideswipe collisions and both the total number of personal injury crashes and severe crashes. Also, it is deemed that each factor used as an independent variable for the SPF model has strong correlation with the total number of personal injury crashes and severe crashes, and impacts general traffic crashes as a whole. CONCLUSIONS: This study suggests the following should be considered in pre-signal installation on intersections. 1) U-turns allowed in the front and rear 2) A high number of roads that connect to the intersection 3) Many right-turn traffic flows 4) Crosswalks installed in the front and rear 5) Insufficient left-turn lanes compared to left-turn traffic flows or no left-turn-only lane.