• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.42-60
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• 2024

This study analyzed the characteristics of mixed traffic flows with autonomous vehicles on highway weaving sections and assessed the safety of vehicle-following pairs based on surrogate safety indicators. The intelligent driver model (IDM) was utilized to emulate the driving behavior of autonomous vehicles, and the weaving sections were divided into lengths of 300 and 600 meters for analysis within a micro-traffic simulation (VISSIM). Although significant differences were found in the average speed, density, and headway between the two sections through t-test results, no significant differences were observed when comparing the number of conflicts per indicator and the vehicle-following pair. Four safety indicators were selected for the mixed traffic evaluation based on their ability to represent risk levels similar to those perceived by drivers. The safety analysis, based on the selected four indicators, determined that autonomous vehicles following other autonomous vehicles were the safest pairing. Future research should focus on integrating these indicators into a single comprehensive index for analysis.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.2
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• pp.45-56
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• 2021

In platoon driving, several autonomous vehicles communicate to exchange information with each other and drive in a single cluster. The platooning technology has various advantages such as increasing road traffic, reducing energy consumption and pollutant emission by driving in short distance between vehicles. However, the short distance makes it more difficult to cope with an emergency accident, and accordingly, it is difficult to ensure the safety of platoon driving, which must be secured. In particular, the unexpected situation, i.e., variability that may appear during driving can adversely affect the safety of platoon driving. Because such variability is difficult to predict and reproduce, preparing safety guards to prevent risks arising from variability is a challenging work. In this paper, we studied a simulation method to avoid the risk due to the variability that may occur while platoon driving. In order to simulate safe platoon driving, we develop diverse scenarios considering the variability, design and apply safety guards to handle the variability, and extends the detail functions of VENTOS, an open source platooning simulator. Based on the simulation results, we have confirmed that the risks caused form the variability can be removed, and safe platoon driving is possible. We believe that our simulation approach will contribute to research and development to ensure safety in platoon driving.

• Information and Communications Magazine
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• v.34 no.5
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• pp.10-18
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• 2017

본고에서는 자율주행 완성차와 자율주행 융합 부품 관련 기술과 국내외의 자율주행자동차 산업정책과 기술 개발 동향을 살펴본다. 자율주행 차량은 고안전, 고편의, 친환경, 신생태계의 자동차 산업에서의 4가지 미래 키워드를 만족시키는 기술로서 국가차원의 전략적 양성이 필요하다. 자율주행자동차 산업은 자동차 산업 생산기반 및 우리나라의 IT, 반도체 등의 기술 활용이 가능하며, 아직 상용화 되지 않은 분야로서 자율주행 분야의 상용화 기술 조기 확보 시 세계시장을 선점 할 수 있다. 따라서 자율주행 완성차 및 부품업체 등의 복수 수요기관이 참여하여 중소, 중견 부품업체 수요처 다각화 및 생태계 체질 개선, 자율주행 핵심부품 및 제어를 위한 SW 등 원천기술 확보 및 수입대체, 자율주행 기술과 관련 센서 선도기술 개발 및 글로벌 중견기업 육성을 기대 할 수 있다. 또한 빠르게 자율주행자동차 관련 기술개발이 진행되고 전장 부품이 자동차에서 차지하는 비중이 커짐에 따라 서로 연결되어 동작하는 전기전자 시스템의 기능안전 확보의 필요성이 대두되고 있다. 이미 해외에서는 자동차 전자제어 시스템 의무 장착을 강화시키는 추세이며 차량 안전 확보를 위해 전자제어장치의 기능 안정성의 중요성과 기술 표준의 필요성을 기반으로 자동차 기능 안전선 국제 표준을 규격화하고 있다. 따라서 본고에서는 국내외의 자율주행차량 분야의 산업 현황과 기술 동향을 살펴봄으로써 시장의 현황을 파악하고 자동차 기능 안전성 국제 표준에 관하여 알아본다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.1
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• pp.91-102
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• 2019

Autonomous vehicles can be exposed to severe danger when failure occurs in any of its components. For this reason many countries are making efforts on the legislative issue how to objectively evaluate failure safety of an autonomous vehicle when such a vehicle is commercially available to a customer in the near future. In level-3 automation, a driver must take over the control of his vehicle when failure occurs, and the driver's controllability must be secured for escape from the imminent danger. In this paper, quantitative methods have been developed for evaluating failure safety of the level-3 autonomous vehicle, and they were validated by simulation. And also, we confirmed that the proposed evaluation method can quantitatively evaluate the failure safety.

• Journal of Korean Society of Transportation
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• v.36 no.1
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• pp.38-50
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• 2018

Emerging automated driving environments will lead to a mixed traffic flow depending on the interaction between automated vehicles (AVs) and manually driven vehicles (MVs) because the market penetration rate (MPR) of AVs will gradually increase over time. Understanding the characteristics of mixed traffic conditions, and developing a method to control both AV and MV maneuverings smoothly is a backbone of the traffic management in the era of automated driving. To facilitate smooth vehicle interactions, the maneuvering of AVs should be properly determined by various traffic and road conditions, which motivates this study. This study investigated whether the aggressiveness of AV maneuvering, defined as automated driving aggressiveness (ADA), affect the performance of mixed traffic flow. VISSIM microscopic simulation experiments were conducted to derive proper ADAs for satisfying both the traffic safety and the operational efficiency. Traffic conflict rates and average travel speeds were used as indicators for the performance of safety and operations. While conducting simulations, level of service(LOS) and market penetration rate(MPR) of AVs were also taken into considerations. Results implies that an effective guideline to manage the ADA under various traffic and road conditions needs to be developed from the perspective of traffic operations to optimize traffic performances.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.30-42
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• 2023

Various studies have been conducted using microtraffic simulation (VISSIM) to analyze the safety of traffic flow when introducing autonomous vehicles. However, no studies have analyzed traffic safety in mixed traffic while considering the driving behavior of general vehicles as a parameter in VISSIM. Therefore, the aim of this study was to optimize the input variables of VISSIM for non-autonomous vehicles through genetic algorithms to obtain realistic behavior. A traffic safety analysis was then performed according to the penetration rate of autonomous vehicles. In a 640 meter section of US highway I-101, the number of conflicts was analyzed when the trailing vehicle was a non-autonomous vehicle. The total number of conflicts increased until the proportion of autonomous vehicles exceeded 20%, and the number of conflicts decreased continuously after exceeding 20%. The number of conflicts between non-autonomous vehicles and autonomous vehicles increased with proportions of autonomous vehicles of up to 60%. However, there was a limitation in that the driving behavior of autonomous vehicles was based on the results of the literature and did not represent actual driving behavior. Therefore, for a more accurate analysis, future studies should reflect the actual driving behavior of autonomous vehicles.

• International Journal of Highway Engineering
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• v.10 no.2
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• pp.135-143
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• 2008

According to the present highway design criteria, there are minimum standards which re ade from special design speeds. If some highways are satisfied the standards, it regards he highway as safety. In reality, however, most drivers drive a car at different speed compared with design speed. It is very dangerous for drivers especially at transition sections between curve and horizontal curve sections. Hence, this study calculated the rate of changing and horizontal acceleration at each section. Moreover, this study evaluated thesafety of design at curve transition sections and then calculated lateral acceleration and curve radii. This study found the minimum standards which are using as basic safety standards are not appropriate for measuring driver's safety.

• Journal of Korean Society of Transportation
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• v.36 no.2
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• pp.67-85
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• 2018

Vehicle platooning through wireless communication and automated driving technology has become realized. Platooning is a technique in which several vehicles travel at regular intervals while maintaining a minimum safety distance. Truck platooning is of keen interest because it contributes to preventing truck crashes and reducing vehicle emissions, in addition to the increase in truck flow capacity. However, it should be noted that interactions between vehicle platoons and adjacent manually-driven vehicles (MV) significantly give an impact on the performance of traffic flow. In particular, when vehicles entering from on-ramp attempt to merge into the mainstream of freeway, proper interactions by adjusting platoon size and inter-platoon spacing are required to maximize traffic performance. This study developed a methodology for establishing operational strategies for truck platoonings on freeway on-ramp areas. Average speed and conflict rate were used as measure of effectiveness (MOE) to evaluate operational efficiency and safety. Microscopic traffic simulation experiments using VISSIM were conducted to evaluate the effectiveness of various platooning scenarios. A decision making process for selecting better platoon operations to satisfy operations and safety requirements was proposed. It was revealed that a platoon operating scenario with 50m inter-platoon spacing and the platoon consisting of 6 vehicles outperformed other scenarios. The proposed methodology would effectively support the realization of novel traffic management concepts in the era of automated driving environments.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.698-701
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• 2020

여러 대의 자율주행 차량이 하나의 그룹을 형성하여 주행하는 군집주행은 미래 고속도로 교통 시스템의 핵심 기술이다. 이러한 군집주행에서 발생할 수 있는 다양한 상황에서의 안전을 고려하는 일은 단독 자율 주행에서의 경우보다 더 어렵다. 다양한 군집주행의 안전 위협 요인 중, 의도하지 않은 동작으로부터 자율주행 차량의 안전성을 향상하는 방법을 가이드하기 위하여 새로운 표준 ISO/PAS 21448이 제정되었다. 본 논문에서는 ISO/PAS 21448 표준이 다루는 시나리오를 통해 군집주행에서 발생할 수 있는 의도하지 않은 상황의 극복을 위한 방법을 제시하였다. 특히 군집주행 시뮬레이터인 VENTOS를 이용하여 본 논문에서 제시하는 방법이 안전한 군집주행이라는 목표를 달성할 수 있음을 확인하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.299-312
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• 2021

Autonomous vehicles using V2X can drive safely information on areas outside the sensor coverage of autonomous vehicles conventional autonomous vehicles. As V2X technology has emerged as a key component of autonomous vehicles, research on V2X security is actively underway research on risk analysis due to failure of V2X communication is insufficient. In this paper, the service scenario and function of autonomous driving system V2X were derived by presenting the intersection scenario of the autonomous vehicle, the malfunction was defined by analyzing the hazard of V2X. he ISO26262 Part3 process was used to analyze the risk of malfunction of autonomous vehicle V2X. In addition, a fault injection scenario was presented to verify the fail-safe of the simulation-based intersection scenario.