PURPOSES : Driving simulations are widely used for safety assessment because they can minimize the time and cost associated with collecting driving behavior data compared to real-world road environments. Simulator-based driving behavior data do not necessarily represent the actual driving behavior data. An evaluation must be performed to determine whether driving simulations accurately reflect road safety conditions. The main objective of this study was to establish a methodology for assessing whether simulation-based driving behavior data represent real-world safety characteristics. METHODS : A 500-m spatial window size and a 100-m moving size were used to aggregate and match the driving behavior indicators and crash data. A correlation analysis was performed to identify statistically significant indicators among the various evaluation metrics correlated with crash frequency on the road. A set of driving behavior evaluation indicators highly correlated with crash frequency was used as inputs for the negative binomial and decision tree models. Negative binomial model results revealed the indicators used to estimate the number of predicted crashes. The decision-tree model results prioritized the driving behavior indicators used to classify high-risk road segments. RESULTS : The indicators derived from the negative binomial model analysis were the standard deviation of the peak-to-peak jerk and the time-varying volatility of the yaw rate. Their importance was ranked first and fifth, respectively, using the proposed decision tree model. Each indicator has a significant importance among all indicators, suggesting that certain indicators can accurately reflect actual road safety. CONCLUSIONS : The proposed indicators are expected to enhance the reliability of driving-simulator-based road safety evaluations.

본 논문에서는 다양한 기상 조건에서 시인성과 내구성을 향상시키도록 설계된 도로 표시용 UV 경화 코팅 시스템 개발을 위해 수행한 연구의 결과를 나타내었다. 제조된 UV 코팅을 사용해 차선 표시의 재귀반사도와 내마모성을 강화하고 포장가속시험(APT), 휠 트래킹 내구성 테스트 등 다양한 테스트를 통해 성능을 평가하였다. 이 결과를 바탕으로 도로 안전을 위한 야간 시인성 및 미끄럼을 개선하 고자 한다.

서울시와 같은 도심지의 경우 상수도관, 하수관, 가스관, 통신․전기선과 같은 인프라 시설물을 도로포장 하부에 매설하고 있다. 그 러나 도로 지하에 각종 시설물을 매설하거나 유지보수 등으로 인해 노면을 굴착할 경우, 포장체 구성에 불연속면을 생성하여 이에 대 한 복구가 적절하지 않았을 경우 지반침하, 포장 노면 균열, 평탄성 불량 등의 발생으로 도로 이용자의 승차감 저하 및 노면배수 불량 으로 인한 차량 주행의 안전성 저하, 보도의 경우 통행인의 불편 초래 및 안전사고를 유발할 수 있다. 그러나 현재 서울시의 도로굴착복구 공사는 도로 이용자의 편의를 위해 당일 굴착·당일 복구를 원칙으로 하고 있으며, 이를 위해 주 간 공사 및 장시간 교통통제를 지양하고 있어, 하루 중 야간 8시간 정도로 공사 시간이 부족하고 수많은 공사가 산발적으로 시행됨에 따라 관리 감독이 어려워 시공 품질관리가 미흡하며, 특히 지하 매설물 공사 이후 포장층 하부의 되메우기 공정은 다짐 작업이 제대 로 이루어지지 않는다. 일반적으로 서울시 도로굴착복구 공사는 공사 당일 임시포장을 시행하고, 일정 기간 경과 후 차로 단위로 항구 포장 복구를 시행하고 있으며, 이로 인한 도로 평탄성 불량으로 소음․진동 발생 및 포장 조기 파손의 원인으로 작용하고 있다. 특히 되메우기 공정의 경우, 현행 시방서에 따르면 신속한 되메움 복구 및 관로 주변의 조밀한 충진을 목적으로 관로 주변을 양질의 모래로 시공하는 것을 원칙으로 하고 있으나, 기존 되메움 재료인 모래는 결속력이 약해 인접 구간 공사 시 세굴로 인한 사고 발생 위험 요소를 내재하고 있으며, 누수에 의한 세굴 발생시 편토압 등으로 인해 주변 지반의 침하 등 2차 파손을 발생시킬 수 있다.

iRAP(international Road Assessment Program)에서는 최근 다양한 유형의 도로 정밀자료를 바탕으로 한 AiRAP(Accelerated intelligent Road Assessment Program)을 개발하여 여러 국가별 RAP에 확대 적용해나가고 있는 단계에 있다. 2023년부터 국내 도로 여건을 고려한 한국형 도로안전도 평가 프로그램 개발 연구가 진행 중에 있으며, 개발되는 평가항목 및 기준, 평가기술 등에 적합한 도로안전도 평가 기초데이터 역시 유형 및 범위에 변화가 필요해짐에 따라 이를 충족하는 기초데이터 수집이 가능한 도로안전도 조사장비 개발이 기획 되었다. 이에 따라 본 연구에서는 고사양의 360도 도로영상 촬영장치와 360도 128채널 LiDAR 센서, 정밀 GPS 시스템, 휴대용 운영장 치 등을 갖춘 도로안전도 조사장비를 일반 차량에 탈부착이 가능한 형태로 개발하고자 하였다. 본 개발 장비로 취득 가능한 도로영상 및 점군데이터를 활용하여 AiRAP 자동분석을 통한 도로안전도 평가가 가능한데, 이를 통해 객관적이고 신뢰성 높은 평가가 가능할 것으로 기대된다.

최근 결빙으로 인한 교통사고가 빈번히 발생하고 있으며, 도로순찰시 육안 인식이 어려운 도로살얼음 검지를 위해 다양한 방식의 검지센서가 도입되고 있다. 본 연구에서는 국내외 상용화되어 있는 차량부착식 노면상태 검지센서에 대한 현장 검증을 통해 국내 도 로조건에의 적용 가능성을 검토하였다. 차량부착식 검지센서의 성능을 평가하기 위해 한국건설기술연구원의 연천SOC실증연구센터 내 의 도로기상재현 실험시설에 결빙(Ice), 습윤(Wet), 건조(Dry) 등 3가지의 노면상태가 육안으로 명확히 구분이 가능하도록 도로환경을 구현하였으며, 센서종류별로 차량에 부착하여 다양한 도로상태를 측정하였다. 평가결과 노면상태 측정결과의 정확도는 높은 것으로 나 타났으나, 그 외의 측정항목의 정확도는 상당한 차이가 발생하기도 하였다. 향후 다양한 도로환경 조건에서 추가적인 시험을 통해 차 량부착식 노면상태 검지센서의 현장적용을 기반자료로 활용할 수 있을 것으로 판단된다.

PURPOSES : As evaluation methods for road paving materials become increasingly complex, there is a need for a method that combines computational science and informatics for new material development. This study aimed to develop a rational methodology for applying molecular dynamics and AI-based material development techniques to the development of additives for asphalt mixtures. METHODS : This study reviewed relevant literature to analyze various molecular models, evaluation methods, and metrics for asphalt binders. It examined the molecular structures and conditions required for calculations using molecular dynamics and evaluated methods for assessing the interactions between additives and asphalt binders, as well as properties such as the density, viscosity, and glass transition temperature. Key evaluation indicators included the concept and application of interaction energy, work of adhesion, cohesive energy density, solubility parameters, radial distribution function, energy barriers, elastic modulus, viscosity, and stress-strain curves. RESULTS : The study identified key factors and conditions for effectively evaluating the physical properties of asphalt binders and additives. It proposed selective application methods and ranges for the layer structure, temperature conditions, and evaluation metrics, considering the actual conditions in which asphalt binders were used. Additional elements and conditions considered in the literature may be further explored, considering the computational demands. CONCLUSIONS : This study devised a methodology for evaluating the physical properties of asphalt binders considering temperature and aging. It reviewed and selected useful indicators for assessing the interaction between asphalt binders, additives, and modified asphalt binders and aggregates under various environmental conditions. By applying the proposed methods and linking the results with informatics, the interaction between asphalt binders and additives could be efficiently evaluated, serving as a reliable method for new material development.

PURPOSES : This study intended to derive a methodology that can evaluate water splash caused by distress on the road surface based on experimental methods and to present quantitatively by analyzing the impact on road users. METHODS : Through literature review, the current problems of road pavement and drainage facility standards, the factors of road splash caused by puddle was selected to measure damage. Field measurements were conducted by setting different conditions for each factors and setting different conditions based on the hypothesis. In addition, water splash by surface distress type and puddle was measured to analyze using statistical techniques from correlation to multi-regression. RESULTS : The maximum and effective distance due to road splash increases as the driving speed, regardless of vehicle load and tyre type. Splash was measured according to the type of road distress to analyze the correlation between the influencing factors, and there was a weak correlation between the width and length of the puddle, depth and the effective distance. In addition, the interaction analysis showed that there was an interaction between the width of the water hole and the depth of puddle. Moreover, based on the multi-regression analysis, it was not statistical significant. This is judged to that the number of data samples used for this analysis is limited because the diversity of puddle conditions cannot be set differently for each type of distress. CONCLUSIONS : Since the distress of depending on the size, depth and shape of the road surface, it is necessary to calculate it and present maintenance standards, so this results present an experimental methodology that can intuitively evaluate damage cased by unestablished puddle. From this results, this is expected to be used as a quantitative indicator to evaluate the satisfaction of road users as a functional performance according to road surface condition.

본 연구에서는 다기준 의사결정분석모델을 사용하여 우리나라 전체 풍력에너지의 잠재량을 연산하였다. 이 모델은 육상과 해상의 풍력터빈 2 MW과 3 MW를 기준설비에 대해 용량밀도 및 이용률을 연산하여 이론적, 기술적 잠재량을 산정한 후 환경규제 및 시장지원정책에 따른 환경성과 경제성과 고려하여 시장잠재량을 산정되는데 풍력 자원, 기술, 그리고 입지환경의 영향단계별 설 비용량 및 발전량을 산정하도록 구성된 잠재량은 최종 의사결정 시나리오를 분석하여 정책적 현안을 고려할 수 있도록 확대 구축하 였다. 의사결정 시나리오의 정책적 현안은 도로 및 주거밀집지역으로 부터의 이격거리를 시나리오로 포함하였다. 전문가 협의에 의 해 도출된 2016년 신재생에너지백서 기준의 풍력잠재량의 발전량 110 TWh/년과 설비용량 39 GW는 도로나 주거건물로부터의 이격 거리에 따라 –33% ~ 8%까지 변화가 있었다. 풍력에너지 보급은 도로와 이격거리 강도에 크게 달라질 수 있으며, 잠재량 변화에 대 한 본 연구 결과는 정부의 보급목표 수립과 적정성을 검토하는데 중요하게 활용될 것이다.

PURPOSES : The purpose of this study is to evaluate the effectiveness of self-luminescent road markings using driving simulation. METHODS : In this study, a driving simulation was conducted to evaluate the effectiveness of self-luminescent road markings. The details of this study are as follows. Highway sections were categorized as tunnels, tunnel approaches, bridges, merging areas, mainlines, and curbs. The luminance of the existing road markings was collected through field measurements. The luminance of the self-luminescent road markings was collected through experimental measurements. The luminance of the road markings is converted into a brightness ratio to be applied to the driving simulation. Road facilities at night were visualized during the driving simulation. Driving simulation was tested by 30 participants. Each participant rated the visibility perception of both the road markings ahead of 90 m with a 5-point scale. The log data generated from the driving simulation tests were analyzed. RESULTS : The luminance of the existing road markings and self-luminescent road markings was measured. The luminance of the existing and lab-based road markings was converted into a brightness ratio. The road facilities of highway sections were investigated for driving simulations. The driving simulation was tested by 30 participants. Visibility perception ratings and log data from the driving simulation were analyzed. The average of visibility point increased from 1.01 to 4.63 when self-luminescent road markings were added to the existing road markings. The average speed also increased when self-luminescent road markings were added to existing road markings. CONCLUSIONS : In conclusion, self-luminescent road markings can improve the visibility of road markings and driving speed, particularly in highway sections where driving speed decreases owing to low visibility.

PURPOSES : The purpose of this study was to quantitatively evaluate the variability of LiDAR performance indicators, such as intensity and Number of Point Cloud(NPC), according to various environmental factors and material characteristics. METHODS : To consider the material characteristics of road safety facilities, various materials (Reference Material(RM), reflective sheet, matte sheet, granite, plastic, and rubber) were used in a darkroom, and the performance indicators of LiDAR were repeatedly measured in terms of changes in the measurement distance, rainfall, and angle of observation. RESULTS : In the case of standard reflective materials, the intensity measurement value decreased as the measurement distance and rainfall increased. The NPC showed a tendency to decrease as the measurement distance increased, regardless of rainfall intensity. For materials with high-intensity values, it was found that rainfall intensity and color had negligible effect on the change in intensity compared with the measurement distance. However, for materials with low-intensity values, it was found that the measurement distance, rainfall intensity, and color all had a significant effect on the change in intensity. CONCLUSIONS : For materials with high-intensity values, it was found that rainfall and color had negligible effect on change in intensity compared with the measurement distance. However, for materials with low-intensity values, the measurement distance, rainfall, and color all had a significant effect on the change in intensity value.

PURPOSES : In this study, to improve the quality and construction performance of backfill materials for road excavation and restoration, the basic properties of rapid-hardening materials and stone sludge are analyzed to propose an optimal mix design. METHODS : To utilize rapid-hardening materials and stone sludge as controlled low-strength materials for pipeline construction in downtown areas, specimens were prepared for each compounding condition of fast-hardening materials. Flow, slump, and compressive strength tests were performed at various setting times. Subsequently, the physical and mechanical characteristics of the rapid-hardening backfill material for each mixing factor were analyzed. RESULTS : When ultrafast hardening cement and stone sludge are used, a setting time exceeding 30 min is required for a water–binder (W/B) ratio of 200% or higher. Considering the economic feasibility of ultrafast hardening cement, a W/B of 300% is considered the most suitable when high-performance superplasticizer and retarders are mixed. A flow test was performed on the rapid-hardening backfill material and the results show that if the mixing time exceeds 10 min, then the fluidity decreases rapidly, which necessitates a higher amount of superplasticizer. When ultrafast hardening cement is used, the initial strength (based on 4 h) is 0.7 MPa or higher for all formulations at a W/B ratio of 300%, and the compressive strength decreases slightly as the amount of superplasticizer is increased by 0.1%. CONCLUSIONS : Based on the fluidity and strength of the backfill material, which is composed of a rapid-hardening material and stone sludge, the most optimal performance is achieved when ultrafast-hardening cement with a W/B ratio of 300% is used in addition to a highperformance fluidizing agent 0.3% (wt./B) and retarder 0.2% (wt./B).

PURPOSES : Fine dust significantly affects the atmospheric environment, and various measures have been implement to reduce it. The aim of this study is to reduce fine dust on roads by implementing porous pavements and a clean road system using the low-impact development technique. METHODS : We conducted quality tests (draindown, cantabro loss rate, tensile strength ratio, dynamic stability, and indoor permeability coefficient tests) and performance evaluation (dynamic modulus and Hamburg wheel-tracking tests) on the porous asphalt mixture. Subsequently, we constructed a porous pavement road in a test bed and conducted a permeability test. In the test bed, we installed a nozzle, a water tank, and a fluid pump to water the roadside. After the clean road system was completely installed, we measured the concentration of fine dust before and after water was sprayed. Additionally, we conducted a total suspended solids (TSS) test to confirm the reduction in re-suspended dust. RESULTS : All results from the quality test of the porous asphalt mixture satisfy the standards stipulated by the Ministry of Land, Infrastructure and Transport. Results from the dynamic modulus test show a low plastic deformation resistance but a high fatigue crack resistance. The results from the Hamburg wheel-tracking test satisfy the U.S. Department of Transportation standards. After the porous pavement was constructed, a permeability test was conducted, and the result satisfies the standard value. Using a particle counter, we measured the concentration of fine dust before and after water spraying, and results show 12.08% and 10.23% for PM10 and PM2.5 particles, respectively. The results from the TSS test show that after the initial water spray, almost all re-suspended dust are removed from a road. In unfavorable road conditions, almost all re-suspended dust are removed after a second water spray. CONCLUSIONS : The results of all of quality tests performed on a porous asphalt mixture satisfy the standards. By applying the results to a test bed, the problem of securing water is solved. Using the clean road system, 12.08% and 10.23% of PM10 and PM2.5 particles are removed, respectively. The system removes PM10 particles (larger particles) more effectively compared with PM2.5 particles. IN the future, we plan to revise the maintenance plan such that the porous pavement can exhibit long-term performance. Because pipe freezing may occur in the winter, we plan to analyze the periodic maintenance plan of the porous pavement and develop a solution to mitigate the issue of freezing pipes in the winter.

PURPOSES : Aiming to evaluate the consistency of road markings at night, the luminance values of road markings at night were compared for merging and diverging areas. METHODS : To evaluate the consistency of road marking at nighttime in merging and diverging areas, the highway geometric structures and luminance of the road markings were collected and analyzed together at the merging and diverging areas. "Luminance" in this study referred to the overall luminance of the road markings as reflected together from surrounding lights, such as moonlight or artificial lights. The luminance of the road markings 90 m ahead of the driver were used. The measured luminance values were analyzed based on the difference ratios and an analysis of variance. RESULTS : Based on a grouping of three categories (interchanges (ICs), merging, and diverging areas), it was found that the difference ratios and analysis of variance values from the ICs and merging and diverging areas were not consistently acceptable. CONCLUSIONS : After evaluating the consistency of road markings at night in the merging and diverging areas, it can be concluded that there is a need for more consistency in the luminance on merging and diverging areas on highways. To enhance consistency, more dedicated lighting guidance for merging and diverging areas on highway areas may be necessary.