This study analyzes the effects of speed humps installed and operated as traffic safety facilities on emergency-vehicle operations and route selection during dispatch, with emphasis on the perceptions and experiences of field practitioners in Busan, Korea. A survey was conducted with 294 firefighters affiliated with the Busan Metropolitan City Fire and Disaster Headquarters. Factors influencing their intention to change dispatch routes were empirically identified through descriptive statistical analysis and binary logistic regression analysis. The physical impacts of speed humps, the perceptions of installation standards, and the effects of job duties and vehicle characteristics on route-change decisions were examined. The intention to change routes due to speed humps was determined not merely based on perceived inconvenience but also by a combination of factors, including the emergency-vehicle type, whether the respondent was responsible for driving, experiences of equipment vibration and falling inside the vehicle, perceptions regarding the necessity to improve installation standards, and job-rank characteristics. In particular, the experience of equipment vibration inside vehicles and perceptions of the necessity to improve installation standards were identified as key factors that more than doubled the likelihood of route changes. Speed humps are not only traffic-calming devices intended to reduce vehicle speed but also traffic facilities that directly affect behavioral decision-making related to actual emergency dispatch strategies and route selection. Additionally, the results suggest that the current installation standards and operational system for speed humps do not sufficiently reflect the driving characteristics of emergency-response vehicles.

도로 운송 부문은 전 세계 에너지 관련 온실가스 배출의 약 23%를 차지하며, 전 세계적인 물류 수요 증가와 도시화로 인 해 향후에도 지속적인 증가 추이를 보일 것으로 예측된다. 이러한 기후 위기 상황에서 차량의 연비를 개선하여 탄소 배출량 을 저감하기 위한 기술적 노력이 다각도로 진행되고 있다. 이 중 도로 포장과 차량 간의 복잡한 물리적 상호작용인 Pavement-Vehicle Interaction(PVI)은 포장체의 처짐으로 인해 발생하는 추가 연료 소모량(Excess Fuel Consumption, EFC)을 결정하는 핵심적인 요소로 주목받고 있다. 본 연구는 도로 포장과 차량의 상호작용으로 인해 발생하는 추가 연료 소모량을 산정함에 있어, 포장 재료의 에너지 소산 특성을 정의하는 감쇠 모델과 하중 하단에서의 포장 처짐 기울기를 계산하는 경사도 산정 방법이 미치는 영향을 정량적으로 비교 분석하였다. 구체적으로, 점성 감쇠 모델과 이력 감쇠 모델을 각각 적용하여 포장의 동적 응답을 도출하였다. 또한, 기 존의 선형 및 상수 기반 경사 산정 방식의 한계를 극복하기 위해, 본 과업에서 제시하는 하중 재하 지점의 순간 기울기를 산정하는 수치적 방법론을 검토하였다. 해석 결과, 선택된 감쇠 모델의 종류와 경사도 산정 방식의 조합에 따라 최종적으로 도출되는 연료 소모량 산정 결과에 유의미한 수치적 차이가 발생함을 확인하였다. 특히 이력 감쇠 모델과 순간 기울기 방식 의 결합은 기존 모델들이 간과했던 포장체의 비대칭적 처짐 거동을 더욱 정밀하게 포착함으로써, 보다 현실적인 탄소 배출 량 예측 근거를 제시하였다

This study analyzes the usage behavior and travel characteristics of shared micro-electric vehicle (micro-EV) mobility services using large-scale empirical data collected over three years (2023-2025) from three pilot regions in Korea: Daejeon, Mokpo, and Jeju Island. By integrating the location-based driving records, user information, trip surveys, and weather data, 66,843 valid trips were extracted, including 49,264 trips matched with user attributes. Usage behavior was first examined through statistical analyses of user demographics and surveybased information on trip purposes, multimodal connections, and user satisfaction. The results indicate that micro-EV services support diverse usage behaviors, ranging from commuting and campus travel to leisure, with distinct regional differences in user composition and service roles. A travel pattern analysis further revealed clear temporal and environmental characteristics, including pronounced seasonal peaks between July and October, higher weekday utilization associated with commuting demand, high concentration of trips during daytime hours, and a nonlinear response to weather conditions, in which usage increased under moderate temperatures but declined during extreme heat, cold, or precipitation. A distance-based analysis showed that micro-EV trips were generally short-distance in nature, while substantial regional variations existed. Daejeon was dominated by ultra-short campus-oriented trips, Mokpo exhibited a broader distribution of short urban trips linked to daily activities and tourism, and Jeju Island demonstrated a higher share of mid-distance trips reflecting industrial park commuting and inter-destination travel. A spatial origin-destination (OD) analysis further highlighted region-specific network structures, with Daejeon forming a compact hub-based network, Mokpo displaying a dispersed pattern centered on major transit facilities, and Jeju Island exhibiting a multipurpose network shaped by commuting and tourism mobility. These findings provide empirical evidence that shared micro-EV services function as flexible region-dependent mobility solutions, underscoring the need for differentiated operational strategies, station-based service planning, and integration with local transport systems to support sustainable urban mobility.

Performance of the hydrogen fuel cell system in a compact special vehicle is mainly influenced by the thermal characteristics of heat release through air flow with electrochemical mechanisms. In this study, numerical analysis has been carried out to investigate air flow and heat transfer characteristics near the fuel cell system for various operating conditions. The cooling characteristics around the radiator system depend on air flow generated by vehicle movement, and the effects of vehicle-induced air flow on the velocity and temperature distributions within the heat release system were examined. These results showed that there are quite complicated air flow around the radiator and fan near the fuel cell system in the vehicle cargo area, and its efficient flow field resulted in cooling performance improvement with driving speed. Hence overall heat release characteristics of the hydrogen fuel cell system are strongly associated with various air flow behavior formed around the compact special vehicle including cargo area.

This study aims to quantitatively and qualitatively evaluate the operational effects of an emergency-vehicle preemption (EVP) system implemented in Anyang City and to derive improvement directions based on both empirical performance outcomes and user-experienced insights. Specifically, this study integrates three complementary methodologies: (1) controlled field tests comparing pre- and post-EVP travel performance under consistent traffic and signal conditions, (2) a one-year operational evaluation using 204 actual dispatch cases collected from six 119 Safety Centers, and (3) a structured survey of frontline firefighters who directly utilized the EVP system during actual emergency responses. The field test results indicated that the average travel time reduced by approximately 44% while the average travel speed increased by approximately 79%, with paired t-test verification confirming that the observed improvements were statistically significant and attributable to the EVP system instead of to random variations. Similarly, the operational evaluation indicated that the actual travel time reduced by an average of 49% compared with navigation-estimated values, whereas the golden-time (5 min) arrival rates for both fire/rescue and medical dispatches exceeded the regional average, with consistent performance demonstrated even under varying travel distances and road complexities. The firefighter survey further reinforced these findings, with respondents reporting clear improvements in golden-time achievement, reduced anxiety toward potential safety risks, and enhanced perceived safety during emergency trials, as well as identified several practical limitations such as route mismatches, occasional system malfunctions, and difficulty in perceiving preemption activation—factors that suggest necessary technical and operational refinements. In general, the EVP system was evaluated as an effective and highly practical tool that improves emergency-vehicle mobility, arrival-time stability, and operational reliability across diverse dispatch conditions. The combined quantitative and qualitative verification in this study underscores its value as a field-proven technology. Future studies should expand to multiregional longitudinal datasets, controlled analyses considering external variables such as traffic volume and weather, and quantitative evaluation of safety-related impacts such as reductions in intersection collisions or on-route risk exposure to assess the system’s broader policy and operational benefits more comprehensively.

This study aims to provide a basis for selecting the appropriate traffic-flow evaluation indicators by quantitatively analyzing the relative importance of such indicators in mixed traffic environments in which automated vehicles (AVs) and conventional vehicles coexist. As AV technology progresses and its adoption increases, establishing reliable evaluation criteria that accurately reflect the characteristics and performance of traffic systems under transitional conditions is crucial. Thus, approximately 40 domestic and international studies were reviewed in this study, from which 45 evaluation indicators were identified. These indicators were classified into three major categories: mobility, safety, and environment. Five frequently used and representative indicators were selected from each category based on the appearance frequency and relevance. An analytic hierarchy process survey was conducted with a group of transportation experts to derive the relative importance (weights) of both the major categories and individual indicators. The analysis revealed that safety (0.53676) was the most important category, followed by mobility (0.34795) and environment (0.11528). After combining the weights of the categories and sub-indicators, the top three indicators, i.e., time to collision (TTC), time exposed to TTC, and deceleration rate to avoid crashes, appeared to be safety related and associated directly with the collision risk. These findings suggest that, in the early stages of AV deployment, traffic evaluations should prioritize safety considerations over mobility or environmental factors to ensure the successful integration of AVs into existing traffic systems.

This study presents the results of compression, drop impact, and vibration durability analyses conducted to evaluate the mechanical reliability of Battery Pack Cases (BPCs) in electric vehicle (EV) systems. BPCs are essential structural components that must endure compressive loads, impact forces, and vibrational fatigue. Finite Element Analysis (FEA) was applied to a representative BPC model to assess deformation, impact resistance, and vibration endurance. The results indicate that the BPC maintained integrity within yield strength limits under compressive loading and effectively absorbed energy under drop impact. Furthermore, Power Spectral Density (PSD) analysis identified stress concentration regions, providing insights for structural optimization. Overall, the findings support the development of lightweight and reliable BPC designs for advanced EV applications.

In this study, the design of shock tower mounting, a type of shock absorber mounting for four-wheel drive vehicles, was addressed through structural analysis. In the case of existing shock tower mounting components, cracks occurred in the shock tower frame side weld joints, so the maximum stress should be reduced to extend the life of the designed components. Based on this, various design changes were performed on the shock tower mounting components, and the maximum stress generated through structural analysis of each design change model was compared. For the structural analysis, a load of 40,000 N was applied in the axial direction of the shock absorber, and the results were relatively analyzed and compared. As a result of the analysis of the shock tower mounting components through the design change, Case 3, a model that alleviated the stress concentration applied to the body mounting, increased the strength compared to the existing model, and the stress in the shock tower frame side weld joints was reduced by 16.3%.

In this study, the effects of a hypothetical autonomous vehicle (AV)-exclusive roadway were estimated through a step-by-step approach using both microscopic and macroscopic simulations. First, the AV-exclusive roadway was classified into four types—entry lanes, mainlines, merging lanes, and intersections—and the C, α, and β values of the Bureau of Public Roads (BPR) function were estimated for each type through a microscopic simulation. These estimated values were then applied to a 3×3 (20 km) network, and a macroscopic simulation was conducted to compare the effectiveness of AVs and conventional vehicles (CVs) in terms of traffic volume and travel time.The analysis showed that for the same travel time, the traffic volume increased by more than 12% with AVs compared to that with CVs. Conversely, for the same traffic volume, the total travel time decreased by 11% for AVs. The estimated capacity of the AV-exclusive roadway, similar to the U-Smartway with a size of 3×3 (20 km), was approximately 400,000 vehicles, which was more than 140% higher than that of CVs. Assuming that each AV carries five passengers, up to two million people can be transported per day, indicating a significant potential benefit. However, these results were based on theoretical analyses using hypothetical networks under various assumptions. Future studies should incorporate more realistic conditions to further refine these estimations.

본 연구는 보행자용 방호울타리의 구조 재료를 FRP로 대체하는 경우의 구조적 타당성을 동적 조건에서 검토하였다. ABAQUS/Explicit 기반의 비선형 충돌 해석을 통해 FRP 복합재 방호울타리의 충돌 거동을 분석하였으며, 각 재료의 비선형성을 반영 한 적절한 재료 모델을 적용하였다. 해석 결과, 기존 강재 방호울타리는 최대 약 167.6 mm의 변위가 발생하였으며, 방호구조물 및 기둥부의 소성 파괴가 관촬되었다. 추가적으로 콘크리트 연석의 고정부에서는 광범위한 파괴 양상이 확인되었으며, 이는 차량 충돌 시 구조체가 보행자 측으로 비산될 수 있는 위험성을 내포한다. 한편, CFRP 및 GFRP 방호울타리는 강재 대비 최대 변위가 약 7.1∼ 9.6%까지 증가하였으며, Hashin 파손 기준에 따른 파손 지수가 최대 1,548.428로 나타나 초기 단계에서 파손이 시작된 것으로 분석 되었다. 이러한 결과는 단순한 재료 치환만으로는 충분한 구조 안전성을 확보하기 어려움을 보여주며, FRP 복합재에 적합한 구조 설계 및 변수 최적화에 대한 추가 연구가 필요함을 시사한다. 아울러 수치해석 결과의 신뢰성 확보를 위해서는 향후 실험적 검증이 필수적이다.

This study collected video footage of accident-risk scenarios on actual roads using automobiles and motorcycles. A total of 191,500 km was driven with three vehicles and one motorcycle, capturing 6,550 near-miss accident videos. The footage was analyzed and categorized based on the 27 parameters of the iGLAD(Initiative for the Global Harmonization of Accident Data) accident categories. Parameters difficult to classify under iGLAD were localized to fit domestic conditions, and further analysis identified areas needing optimization. The categorized data was organized into a web-based database platform, providing statistical analysis and search functions for scenario development. Future use of this data will support the creation of safety evaluation scenarios for autonomous vehicles, enhancing traffic accident investigation and analysis systems. Expanding the database to include data from secondary roads and parking areas is expected to increase its applicability and value.

PURPOSES : This study aimed to derive the factors that contribute to crash severity in mixed traffic situations and suggest policy implications for enhancing traffic safety related to these contributing factors. METHODS : California autonomous vehicle (AV) accident reports and Google Maps based on accident location were used to identify potential accident severity-contributing factors. A decision tree analysis was adopted to derive the crash severity analyses. The 24 candidate variables that affected crash severity were used as the decision tree input variables, with the output being the crash severity categorized as high, medium, and low. RESULTS : The crash severity contributing factor results showed that the number of lanes, speed limit, bus stop, AV traveling straight, AV turning left, rightmost dedicated lane, and nighttime conditions are variables that affect crash severity. In particular, the speed limit was found to be a factor that caused serious crashes, suggesting that the AV driving speed is closely related to crash severity. Therefore, a speed management strategy for mixed traffic situations is proposed to decrease crash severity and enhance traffic safety. CONCLUSIONS : This paper presents policy implications for reducing accidents caused by autonomous and manual vehicle interactions in terms of engineering, education, enforcement, and governance. The findings of this study are expected to serve as a basis for preparing preventive measures against AV-related accidents.

산업화와 도시화의 급속한 발전으로 교통량이 증가하면서, 도로 비산먼지와 같은 대기 오염 문제가 심각해지고 있다. 특히, 도로에 서 발생하는 미세먼지의 주요 원인인 비배기가스의 일환인 도로 비산먼지(Road suspended dust)는 대기 질을 저하시킬 뿐만 아니라, 인 체 건강에도 여러 가지 해로운 영향을 미친다. 이에 비산먼지 예측 모형식을 개발하기 위해 도심부 도로 내 비산먼지 측정차량을 운 영하고 있으나, 측정 시 주변 환경에 영향을 많이 미치기 때문에 보다 신뢰성 있는 결과를 위해서는 앞차에서 발생하는 배기가스 영 향권을 최소화하여 노면-타이어에서 발생하는 순수 비산먼지 농도를 측정할 필요가 있다. 따라서 본 연구의 목적은 차량의 주행 패턴 에 따라 도로 비산먼지 농도가 어떻게 변화하는지를 분석하고, 거리별 배기가스의 영향력을 평가하고자 하였다. 먼저, 이동식 비산먼지 측정차량을 활용하여 측정차량을 기준으로 차량 간의 거리(10m, 20m, 50m)와 도심부에서 발생할 수 있는 대표 적인 주행행태(전방 2대 직진, 전방 2대 평행, 전방 3대 직진)에 따른 도로 비산먼지 농도의 변화를 측정하였다. 실험 결과, 차량 간 거리가 가까운 10m일 때 비산먼지 농도가 가장 높았으며, 이 때의 농도는 20m 또는 50m 거리에서 측정된 농도보다 유의미하게 증가 하는 경향을 보였다. 특히, 20m 거리에서는 비산먼지 농도가 낮아지는 경향이 뚜렷하였으며, 이는 차량의 배기가스가 도로에서 발생하 는 비산먼지에 미치는 영향이 줄어드는 것을 나타낸다. 또한 전방에 3대의 차량이 직진으로 주행할 경우 앞차량에 의해 비산된 먼지 가 계속 공기중으로 비산되어 측정차량에서는 낮게 나타나는 것으로 분석되었다. 이러한 결과는 도시 내에서 비산먼지에 기반한 안전 거리를 설정하는 데 중요한 기초 자료로 활용될 수 있으며, 측정차량 운영 시 앞차에서 발생하는 배기가스의 영향을 최소화하여 비산 먼지 농도만을 측정할 수 있는 자료로 활용될 수 있다. 본 연구는 배기가스가 도로 비산먼지 농도에 미치는 영향을 실증적으로 분석함으로써, 대기질 개선을 위한 보다 효과적인 정책 수립 에 기여할 것으로 기대된다. 궁극적으로, 도심부 도로 내 도로 비산먼지에 대한 영향을 고려할 때 배기가스에 따른 농도 변화를 이해 함으로써, 향후 도시 환경에서의 지속 가능한 교통 관리와 대기질 개선 전략을 개발하는 데 중요한 기초 자료가 될 것으로 판단된다.

Recently, due to the expansion of data communication between objects, research related to data communication technology applied to vehicles is being actively conducted. This study selects a network with Wi-Fi 6, which is advantageous in bandwidth, communication speed, and wireless saturation of a wireless network for mobile terminal data communication, and designs and implements Wi-Fi 6 in a vehicle network. In addition, a continuous variable communication structure is proposed to enable high speed data switching in consideration of the characteristics of mobile communication terminal devics, indicating that connection operation and response speed are improved compared to Wi-Fi standard communication methods, and it can be extended to a system for road networks and autonomous driving by expanding it to various event data communication between vehicles.

PURPOSES : The purpose of this study is to identify the causes and expected problems of traffic flow in connection with ground roads that are expected to become stagnant owing to the increase in underground road infrastructure, and to derive methods to solve the problem in the future. METHODS : The basic design of underground roads is similar to that of tunnels. However, there is a point where the slope is large as the entering and exiting sections move underground. The ability of a heavy vehicle to assume a mound may vary depending on the slope. Therefore, in this study, a connection path section with a long slope was constructed using VISSIM, a simulation program, and it was verified whether analysis related to the slope and heavy vehicles in an underground road can be performed in the simulation. Subsequently, an analysis was conducted by setting a scenario and an effect index. In particular, this study analyzes internal delay patterns in the event of an unexpected situation on an underground connection road by performing shock wave analysis to analyze speed reduction according to heavy vehicles and slopes. RESULTS : A correlation between the slope of the underground road and decrease in the average speed according to the increasing rate of heavy vehicles was established. It was also possible to analyze the maximum length and duration of the delay connected to the rear in the event of a delay in the underground road and the shock wave speed transmitted to the rear. The analysis showed that the rate of increase in problems owing to delays ranged from 5% to 20% for the ratio of heavy vehicles. In particular, all effect scales increased significantly at a 9% slope. CONCLUSIONS : This study analyzes the causes of land congestion (slope and heavy vehicle mixing rate), which can be a major problem in underground roads in the future. In the future, by establishing lane-specific speed control strategies and lane control strategies based on this study, it will be necessary to derive solutions such as introducing traffic safety on the underground road by minimizing the shock wave delivered to the rear by providing information on traffic communication conditions inside the underground road to individual vehicles.

PURPOSES : This study aims to perform a quantitative analysis of Forward Collision Warning and crash frequency using heavy vehicle driving data collected in expressway driving environments, and to classify the driving environments where Forward Collision Warnings of heavy vehicles occur for accident-prone areas and analyze their occurrence characteristics. METHODS : A bivariate Gaussian mixture model based on inter-vehicle distance gap and speed-acceleration parameters is used to classify the environment in which Forward Collision Warning occurs for heavy vehicles driving on expressways. For this analysis, Probe Vehicle Data of 80 large trucks collected by C-ITS devices of Korea Expressway Corporation from May to June 2022. Combined with accident information from the past five years, a detailed analysis of the classified driving environments is conducted. RESULTS : The results of the clustering analysis categorizes Forward Collision Warning environments into three groups: Group I (highdensity, high-speed), Group II (high-density, low-speed), and Group III (low-density, high-speed). It reveals a positive correlation between Forward Collision Warning frequency and accident rates at these points, with Group I prevailing. Road characteristics at sites with different accident incidences showed that on-ramps and toll gates had high occurrences of both accidents and warnings. Furthermore, acceleration deviation at high-accident sites was significant across all groups, with variable speed deviations noted for each warning group. CONCLUSIONS : The Forward Collision Warning of heavy vehicles on expressways is classified into three types depending on the driving environment, and the results of these environmental classifications can be used as a basis for building a road environment that reduces the risk of crashes for heavy vehicles.