간행물
한국도로학회논문집 KCI 등재 International journal of highway engineering
- 발행기관 한국도로학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1738-7159 (Print)2287-3678 (Online)
- 수록기간 1999 ~ 2025
- 주제분류 공학 > 토목공학 공학 분류의 다른 간행물
- 십진분류KDC 534DDC 625
권호리스트/논문검색
제27권 제6호 통권134호 (2025년 12월) 26건
1.
2025.12
구독 인증기관 무료, 개인회원 유료
Pavement friction under wet conditions is a critical factor affecting driving safety and is determined significantly by water-film thickness (WFT). Although current road geometric design standards incorporate wet-pavement friction coefficients as design parameters, they do not adequately account for the effects of WFT. This study estimates the variation in the coefficient of friction caused by changes in the WFT and applies the results to the calculation of stopping sight distance (SSD) and radius of curvature (RC), which are essential elements in road geometry design. Through this approach, the study identifies the limitations of current standards and proposes potential improvements. WFT was estimated using the Gallaway model, which was previously verified through comparative analysis and experimental validation. The model incorporates key influencing factors such as rainfall intensity, pavement slope, drainage path length, and mean texture depth. Based on the estimated WFT, the longitudinal and lateral friction coefficients were calculated using Gallaway’s SN and Lamm’s models, respectively. Using these friction values, the SSD and RC were evaluated under various pavement and environmental conditions. Furthermore, comparisons with existing design guidelines were performed to assess whether the predicted values satisfy the standards under different conditions. Additionally, areas requiring improvement were identified. The analysis confirmed that WFT increases with rainfall intensity and drainage path length, whereas it decreases as the pavement slope, mean texture depth, and tread depth increase. An increase in the WFT significantly reduces the friction coefficient, which consequently increases the SSD and required RC. In particular, under conditions such as heavy rainfall, worn treads, long drainage paths, and shallow surface textures, the calculated SSD and RC typically exceed the minimum requirements of current road-design standards. By contrast, ensuring sufficient surface texture effectively maintains friction performance and mitigates increases in the SSD and RC. The findings of this study suggest that current road-design standards—based on dry or vaguely defined wet conditions—may not sufficiently address the effects of WFT on pavement friction. A quantitative, WFT-based approach is required for more realistic friction estimations. To enhance safety in rainy conditions, road designs should incorporate structural and material improvements, such as optimizing pavement slopes, reducing the drainage path length, maintaining adequate surface texture and tread depth, and adopting high-performance surfacing materials. Additionally, dynamic speed-management systems during rainfall and preventive maintenance for sections with inferior drainage should be considered to improve driving safety under wet weather conditions.
5,800원
2.
2025.12
구독 인증기관 무료, 개인회원 유료
This study focuses on the issue of premature failure in patched sections of asphalt concrete overlays during the service life of existing concrete slabs. These failures are typically exacerbated by extreme weather and heavy traffic. To overcome the low durability and moisture susceptibility of conventional patching materials, the applicability of the GA (Guss Asphalt) mixture, which is known for its excellent waterproofing and adhesion properties, was investigated. Additionally, the fundamental performance characteristics of GA, including its initial stability, moisture resistance, porosity, and plastic-deformation resistance, were evaluated. In this laboratory study, the stability, flow value, and porosity (V a) of six types of pavement patch materials (including GA/MA (Mastic Asphalt), HMA (Hot Mix Asphalt), and CMA (Cold Mix Asphalt) mixtures) were evaluated under various initial curing conditions (3–48 h) and environmental conditions (air and water at 25 °C). Additionally, a wheel tracking test was performed in air conditions at 25 °C to compare and analyze the dynamic stability and plastic-deformation resistance. The results show that GA exhibited the highest stability under all conditions. Its stability increased significantly after 48 h of curing in water, thus demonstrating its superior moisture resistance compared with that of HMA, whose stability decreased significantly. Porosity analysis indicates that the GA/MA mixtures (GMA, PMA, and PGMA) exhibited low porosity (< 1%) and high saturation (> 97%), thus confirming a dense pore structure. Furthermore, the results of the wheel tracking test show that the HMA and GA mixtures exhibited the highest dynamic stability under both 24- and 48-h curing durations. In particular, the GA mixture showed the smallest rutting depth (0.9–1.0 mm), thus indicating its superior resistance to plastic deformation. By contrast, the CP-A mixture showed the largest rutting depth (32.5–38.4 mm), thus indicating the greatest susceptibility to plastic deformation, whereas the CP-B mixture exhibited relatively stable performance with a rutting depth of 5.4–5.6 mm. In general, the GA/MA mixtures exhibited the best performance in terms of long-term stability (48 h of curing), moisture resistance, and plastic-deformation resistance compared with conventional HMA and CMA (CP-A and CP-B) mixtures. GA mixtures are considered the optimal alternative for road patching and repair owing to their excellent moisture resistance and plastic-deformation resistance at 25 °C. However, their field application requires consideration of various environmental conditions, thus necessitating further comprehensive investigations into their crack resistance, adhesion, and plastic-deformation behavior.
5,100원
3.
2025.12
구독 인증기관 무료, 개인회원 유료
The engineered materials arresting system (EMAS) is a safety facility installed at the end of runways to safely stop aircraft when runway overruns occur. The EMAS comprises porous panels composed of specialized materials; however, direct exposure to environmental factors, such as moisture infiltration, freeze–thaw cycles, and ultraviolet radiation, may cause performance degradation. In regions with four distinct seasons and significant temperature variations, such as South Korea, changes in the physical properties and durability of porous panels can pose significant challenges. Therefore, a protective top coating must be applied to EMAS panels to protect the panels from environmental stress and ensure long-term durability. This study presents a preliminary investigation into the development of a high-performance polyureabased top coating to effectively protect the components of an EMAS and crushable concrete panels as well as to maintain the system’s long-term durability and arresting performance. First, optimal formulations were determined via a design study, where the index ratio (the equivalent ratio of polyurea resin to the curing agent) and the NCO content of the isocyanate component were varied. Second, the curing behavior, mechanical properties, and temperature dependence were evaluated. Polyurea—a high-performance elastomer formed by the reaction between isocyanate and amine-based curing agents—exhibits rapid reactivity, complete waterproofing, excellent flexibility, and elasticity, thus satisfying the essential requirements of EMAS top coatings. Considering the balance between stiffness and flexibility, an index ratio of 1.05 and an NCO content of 16.0% were identified as the optimal mix design. Mechanical testing demonstrated a high tensile strength of 20.0 MPa, an outstanding elongation at break of 388%, and a tear strength of 100 N/mm, thus indicating sufficient durability and flexibility to withstand aircraft jet blast and temperature fluctuations. Temperature-dependence tests confirmed that the elongation remained at 136% (at -20 °C) and the tensile-strength ratio at 68% (at 60 °C), thus demonstrating that the coating can maintain stable performance in environments with significant seasonal temperature variations.
4,000원
4.
2025.12
구독 인증기관 무료, 개인회원 유료
The objective of this study is to quantitatively evaluate the effect of pavement aging on the blow-up occurrence temperature of jointed concrete pavements. Pavement aging reduces the effective joint width through joint deterioration and infiltration of incompressible materials, thus decreasing the trigger temperature for pavement growth (TTPG). The TTPG is defined as the concrete temperature at which all transverse contraction joints within the expansion joint system are completely closed and the slabs begin to behave as a single structural unit. Once the maximum concrete temperature (Tmax) exceeds the TTPG, the temperature difference (ΔT = Tmax−TTPG, i.e., the effective temperature) results in compressive stresses within the slab, thus initiating the blow-up mechanism. A lower TTPG increases ΔT, thus accelerating thermal expansion and the accumulation of the annual maximum compressive stress. Expansive products generated by the alkali-silica reaction (ASR) and higher coefficients of thermal expansion (CTEs) further intensify internal compressive stresses, thus inducing blow-up at lower temperatures. Moreover, the subbase type affects the blow-up occurrence temperature owing to the differences in geometric imperfections and the slab–subbase friction. This study employs the pavement growth and blow-up analysis model to estimate blow-up occurrence temperatures, thus explicitly addressing the combined effect of pavement aging, ASR, CTE, and subbase type.
4,300원
5.
2025.12
구독 인증기관 무료, 개인회원 유료
In response to the contemporary demands of the construction industry for climate-change action and carbon neutrality, this study conducts a comprehensive analysis of the applicability of Portland limestone cement (PLC)—a notable sustainable alternative to ordinary Portland cement (OPC)—for highway pavement applications. PLC is an eco-friendly material that reduces carbon-dioxide emissions and energy consumption compared with OPC by reducing the clinker ratio in its manufacturing process. This study examines the fundamental physical and chemical mechanisms of PLC concrete and compares its mechanical performance and durability characteristics with those of OPC concrete. The results indicate that PLC concrete exhibits performance levels equivalent to or superior to those of OPC in key metrics such as compressive and flexural strengths, with particularly outstanding performance in durability aspects such as chloride-penetration resistance. However, the potential for early-age cracking and compatibility issues with certain admixtures are identified as challenges that must be addressed for the wider field application of PLC concrete. Thus, this study proposes the integration of nanotechnology to overcome these technical limitations and maximize performance. Specifically, methods to significantly improve the strength, abrasion resistance, fatigue resistance, and crack-control performance by utilizing nanomaterials such as Nano- , Nano- , and graphene oxide ( ) to control the microstructure of PLC concrete are presented. Finally, a comprehensive roadmap is proposed to enhance the field applicability of PLC concrete for highway pavements and contribute to the construction of sustainable social infrastructure through three key strategies: mix design optimization, consideration of regional environmental conditions, and integration of nanotechnology.
4,000원
6.
2025.12
구독 인증기관 무료, 개인회원 유료
More than half of the deaths caused by road accidents occur at night. For decades, engineers and scientists have been investigating and proposing numerous devices and measures to improve safety during nighttime driving. However, relatively new safety devices and applications are few, and their effects on nighttime driving remain ambiguous. Thus, the effects of a light-emitting diode (LED) road stud on night-time driving are investigated in this study. Thirty participants completed nighttime driving under four conditions on the same unlit mountainous road using a driving simulator. The four conditions were as follows: 1) no Rain/no studs, 2) rain/no studs, 3) rain/studs only on the centerline, and 4) rain/studs on the centerline and edges. Significant outcomes were obtained when rainy conditions were compared with clear weather conditions. The results suggest relative validity between the real world and a specified driving simulation. Significant safety benefits were indicated when comparing stud conditions (studs only on the centerline and studs on both sides) with the no-stud condition. Interesting results were obtained when comparing the case of studs only on the centerline with the case of studs on the centerline and on the edges. The right-edge crossing condition with LED studs on both sides showed better results by approximately 30% compared with the condition with LED studs only on the centerline. By contrast, the center-crossing condition with LED studs only on the centerline showed better results by more than 50% compared with the condition with LED studs on both sides.
4,000원
7.
2025.12
구독 인증기관 무료, 개인회원 유료
This study proposes a quantitative and systematic evaluation framework for rationally determining investment priorities in maintenance projects for heterogeneous road infrastructures such as bridges and tunnels. In Korea, conventional maintenance decision-making relies significantly on empirical judgments and policy-driven preferences, thus resulting in inefficiencies, inconsistencies, difficulties across facility types, as well as limited transparency in budget allocation. Hence, a multicriteria decision-making model integrating three key indicators–defect (performance), economic value (asset-based benefit), and risk (safety)–is developed. In particular, the economic evaluation introduces the concept of asset-value recovery and employs artificial intelligence-based machine-learning models (i.e., random forest, light gradient boosting machine, and extreme gradient boosting) to estimate reasonable replacement costs and quantify benefits in monetary terms. The proposed model enables the correlation between these quantitative indicators with maintenance project types to prioritize investments by combining benefit scores and risk indices. The case study demonstrates that the proposed framework enhances the objectivity and efficiency of budget allocation and enables data-driven investment prioritization instead of policydependent decisions. Moreover, this approach provides a foundation for transitioning from experience-based decisions to data-driven infrastructure management. This methodology can be further expanded to include probabilistic risk assessment and life-cycle cost-based management frameworks, thus ultimately contributing to sustainable evidence-based decision support systems for national infrastructure asset management.
4,200원
8.
2025.12
구독 인증기관 무료, 개인회원 유료
This study presents analytical and experimental approaches to identify packing factors for polydisperse granular materials that maximize structural strength. The findings indicate that structural strength depends not only on the packing density but also on the particle-size distribution. A higher percentage of large particles correlates with greater structural strength, even for packings with identical density values. Therefore, this study proposes that the criterion for optimal packing should prioritize the maximum structural strength instead of the maximum packing density. This criterion is derived from proposed coordination numbers for polydisperse granular materials, which account for both the compaction degree and the proportion of particles of varying sizes. Physical experiments were conducted to measure the densities of packings with different particle-size distributions, and the experimental results were compared with analytical simulations using the discrete-element method. These comparisons indicate qualitative agreement between experimental and analytical data.
4,000원
9.
2025.12
구독 인증기관 무료, 개인회원 유료
This study evaluates environmental impact factor emissions generated by three concrete-pavement methods. Specifically, internationally commercialized programs are used to calculate the environmental impact factors of selected domestic concrete-pavement projects, thereby identifying areas requiring improvement. This study quantified the material usage and energy consumption associated with the construction and maintenance of three concrete-pavement methods. Using internationally commercialized software, this study evaluated the emissions of environmental impact factors for jointed concrete, continuously reinforced concrete, and mechanized continuously reinforced concrete pavements under three assumed maintenance scenarios for each method. Analysis of the environmental impact factors over a 30-year period under three maintenance scenarios (Cases A, B, and C) shows that, for the three pavement methods, the construction phase is dominant— constituting 70%–99%—across most impact categories, including global warming, smog formation, acidification, eutrophication, human toxicity, ecological toxicity, and respiratory effects. This study analyzes the environmental impact factors during the construction and maintenance processes of three concrete-pavement types using foreign LCI databases and identifies the environmental impacts of each input material. In the future, if LCI and LCIA databases for domestic road pavement materials are established and analyses are conducted based on the conditions presented in this study, then a foundation can be realized for the development of environmentally friendly materials and methods.
4,900원
10.
2025.12
구독 인증기관 무료, 개인회원 유료
This study analyze whether the fare-free bus policy (“Support Program for Promoting Public Transportation Use Among the Elderly and Others”) implemented in Chungnam in July 2019 increases the bus-usage probability among policy beneficiaries (elderly individuals aged 75 and older) in Chungnam. A difference-in-differences approach was utilized to empirically analyze the change in the bus-usage probability among residents aged 75 years and older in Chungnam following the implementation of free bus fares. Specifically, the difference in bususage probability before and after the policy was implemented was examined between the treatment group (elderly aged 75 years and older in Chungnam) and control group (elderly aged 75 years and older in other regions or those aged < 75 years in Chungnam). The effectiveness of the policy was evaluated by comparing the changes. For an empirical analysis, data from the “Elderly Status Survey” conducted by the Ministry of Health and Welfare and the Korea Institute for Health and Social Affairs in 2017 and 2023—targeting elderly individuals aged 65 years and older nationwide—were utilized. The results show that the fare-free bus policy implemented in Chungnam in July 2019 for residents aged 75 years and older significantly increased the bus-usage probability among the elderly population in the region as compared with the case for their counterparts in neighboring Chungbuk and Jeonbuk. However, in an analysis limited to Chungnam as the region of study, no statistically significant effect of the policy was observed when the control group was defined as elderly individuals under 75 years of age. Considering the relatively low levels of retirement preparedness of Korea’s elderly population as compared with those other developed countries and mobility limitations that restrict external activities, the fare-free bus policy for residents aged 75 years and older implemented in Chungnam can improve the transportation welfare of vulnerable groups. The empirical results of this study indicate that the effects of such a policy can serve as a basis for the long-term promotion and expansion of related initiatives.
4,000원
11.
2025.12
구독 인증기관 무료, 개인회원 유료
Traffic congestion in tunnels, particularly phantom jams, significantly reduces driving efficiency and increases crash risks. To address this issue, a Pacemaker System (PMS) was implemented in the Geumnam Tunnel along the Seoul–Yangyang Expressway. A PMS aims to stabilize traffic flow and improve operational efficiency by guiding drivers to maintain uniform speeds through sequential LED illumination. This study aims to quantitatively evaluate the effectiveness of a PMS on traffic flow by analyzing Vehicle Detection System (VDS) data collected before and after its implementation. The analysis incorporated Level of Service (LOS) categories A–E, and distinguished between peak and non-peak hours to assess speed improvements and flow stabilization. The results indicated that the PMS increased the average speeds by approximately 6.5% across the LOS A–E conditions, with the most pronounced effects observed in LOS C–E. Furthermore, the speed distribution analysis revealed that the PMS enhanced lower-percentile speeds and reduced speed variance, thereby contributing to improved traffic stability. Statistical tests confirmed that the observed improvements were significant (p < 0.05). These findings demonstrate that the PMS effectively mitigates phantom jams and improves tunnel traffic efficiency, offering empirical evidence to support future PMS deployment and the development of tunnel traffic management policies.
4,000원
12.
2025.12
구독 인증기관 무료, 개인회원 유료
Truck platooning technology, which utilizes vehicle-to-vehicle communication to enable two or more autonomous trucks to travel in a platoon, is garnering attention. However, before platooning is implemented, an environment that can stably maintain a constant speed must be established. Therefore, maintaining a constant speed is a key prerequisite for truck platooning. To overcome the limitations of previous studies, which relied on traffic simulations or limited experiments, this study analyzes second-by-second truck DTG driving records obtained from highways near major domestic ports. Based on these data, a sliding-window technique was employed to detect constant-speed driving patterns and estimate the rate of constant-speed driving by section. The analysis revealed a high rate of constant-speed driving at the Noeun JCT–Dongcheongju IC, where the traffic volume was low and the road alignment was gentle. However, a low rate was observed at the Gunpo IC–Donggunpo IC, where ramp entries and exits were frequent. Subsequently, a multivariate fractional polynomial model was employed to analyze factors influencing constant-speed driving. The main factors identified were speed dispersion, average duration of constantspeed driving, and volume of large trucks per lane. This shows that speed stability, continuity of driving patterns, and vehicle composition within a section are more important factors in determining constant-speed driving than the average driving speed or traffic volume. This study is significant because it empirically elucidates the characteristics and factors influencing constant-speed driving using large-scale field data. Furthermore, it is expected to provide fundamental data for selecting suitable sections for truck platooning and establishing logistics efficiency policies.
4,000원
13.
2025.12
구독 인증기관 무료, 개인회원 유료
Crash risk in metropolitan areas arises from the interaction among driver behavior, enforcement infrastructure, and urban environmental conditions; however, microspatial evidence remains scarce. This study examines the effects of automated speed-enforcement cameras on the crash risk in Seoul at the legal-dong level using the accident risk index, which accounts for both crash frequency and injury severity. The dataset combines crash records, enforcement infrastructure, school-zone information, demographic indicators, and land-use characteristics. Methodologically, a Bayesian negative binomial regression model was employed to address overdispersed crash data, whereas gradient-boosting machine and eXtreme Gradient Boosting models with SHAP interpretations were applied to capture nonlinear effects, heterogeneity, and variable interactions. The results reveal that the crash risk is spatially concentrated, with a small proportion of districts contributing disproportionately to the overall exposure. Regression analysis highlights enforcement and behavioral factors as significant predictors, whereas machine-learning models emphasize the added importance of structural and demographic characteristics, such as road area and floating population. This divergence reflects the sensitivity of the regression to collinearity and linearity assumptions in contrast to the flexibility of tree-based methods in uncovering nonlinear and context-dependent influences. In general, the findings reflect the value of integrating statistical and machine-learning approaches for a more comprehensive understanding of crash risk at the microspatial scale. This study advances the methodological diversity in traffic-safety research and provides practical evidence that cameradeployment strategies should be context sensitive while targeting areas with concentrated risks and distinct structural and demographic profiles.
4,200원
14.
2025.12
구독 인증기관 무료, 개인회원 유료
Using highway accident data, this study predicts the probability of rollover, overturning, and fire accidents and identifies the related risk factors. Whereas existing studies rely primarily on limited explanatory variables and classical statistical models, this study simultaneously enhances predictive performance and interpretability by applying and comparing machine learning-based nonlinear prediction-analysis systems (XGBoost and Shapley additive explanations) with logistic regression, which offers advantages in statistical reasoning. The analysis identifies speeding, segment characteristics (tunnel, ramp, shoulder), and vehicle type (SUV, truck, trailer, and tank lorry) as common key risk factors. These results suggest the necessity of establishing a multilayered management system for speeding, improving facilities centered on high-risk sections (tunnel in/out, ramp, and downhill), performing custom inspections for each vehicle type (load, tire, and brake system), and improving driving behavior (enhancing forward attention, introducing a drowsiness warning system, etc.). This study provides a datadriven empirical basis for identifying the causes of major highway accidents and for designing effective prevention policies.
4,000원
15.
2025.12
구독 인증기관 무료, 개인회원 유료
Human errors committed by traffic managers have consistently been identified as one of the major causes of traffic accidents. In fact, these errors are not merely the result of individual negligence but are closely related to the organizational level of safety culture. This study empirically examines the effects of safety-culture factors on the occurrence of human error through a survey of 100 employees from road and railway traffic control centers. Safety culture was categorized into five dimensions: leadership, rule compliance, reporting system, mutual trust, and learning orientation. Human error was defined based on Rasmussen’s generic error-modeling system (GEMS) as slips, mistakes, or violations. The analysis revealed that leadership and reporting system contributed the most significantly in reducing human error, whereas learning orientation and mutual trust show significant effect. Rule compliance is statistically significant but its effect size is relatively limited. This study transcends the classical perspective of regarding managerial human error as an individual fault and demonstrates that the level of organizational safety culture is a decisive factor in error prevention. Furthermore, the findings provide both academic and practical implications by suggesting directions for strengthening safety culture at the level of traffic-safety policy and organizational management.
4,000원
16.
2025.12
구독 인증기관 무료, 개인회원 유료
Traffic congestion and abrupt speed variations in tunnels increase crash risks and reduce traffic operational efficiency. Thus, a pacemaker system (PMS) was developed to stabilize traffic flow by guiding drivers to maintain uniform speeds through the use of sequentially illuminated LED lights installed along tunnel walls. This study aims to quantitatively evaluate the effects of a PMS on traffic operational efficiency and safety in the Geumnam Tunnel of the Seoul–Yangyang Expressway via a driving simulation. In speed-recovery scenarios, sequential LED lights effectively encouraged drivers to gradually restore their speed. Consequently, the average speed increased significantly, whereas both the difference in speed and the space-varying volatility of speed decreased, thus indicating enhanced driving consistency and improved flow stability. In speed-reduction scenarios, drivers’ deceleration responses were compared under three PMS operational types: flashing yellow, message display, and combined flashing with a message. Combined flashing with a message yielded the most controlled and pronounced deceleration, thus facilitating drivers in reducing their speed smoothly without abrupt braking or instability. The results collectively demonstrate that a PMS can serve a dual function by supporting both speed recovery under normal conditions and safe deceleration in accident cases. These findings provide empirical evidence of the effectiveness of a PMS as an intelligent tunnel-traffic management system and highlight its potential as a proactive safety technology. Furthermore, this study offers practical insights for future PMS designs as well as operational guidelines for enhancing traffic efficiency and driver safety in tunnel environments.
4,000원
17.
2025.12
구독 인증기관 무료, 개인회원 유료
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.
4,200원
18.
2025.12
구독 인증기관 무료, 개인회원 유료
This study aims to develop an underground expressway design for an exit area to mitigate traffic congestion. Thus, we explain the necessity of underground expressways and three reasons for persistent congestion on underground expressways despite an increase in supply. We focus on the first reason, which is a complicated traffic-flow conflict in the exit area, and analyze the traffic flow based on various conditions, such as the exit rate to a nearby interchange and the exit location for underground and ground roads. Consequently, we identify three factors that affect congestion in the exit area. The first factor is the exit rate, where a higher exit rate corresponds to a more severe congestion. The second is the exit location of two roads. When the exit of a road that exhibits a higher exit rate is placed on a curb side, the average delay is reduced. The final factor is the length of the lane-change section, where a longer lane-change section correspond to less congestion. However, after a certain length, the change in congestion is negligible. Based on these results, we suggest revised design guidelines for underground expressways in terms of exit location and the length of lane-change sections.
4,000원
19.
2025.12
구독 인증기관 무료, 개인회원 유료
This study aims to analyze the driving trajectories and lateral behavior characteristics of autonomous vehicles via simulation and to derive the implications for roadway infrastructure design based on the analysis results. A three-lane, one-way autonomous driving simulation environment was established to replicate the actual driving characteristics of autonomous vehicles. Roadways were designed based on domestic road design standards (MLTM, 2020), where horizontal, vertical, and cross-sectional alignments were incorporated and design speeds ranging from 20 to 120 km/h were considered. Curves with minimum radii of 15, 30, 60, …, 710 m were implemented. Autonomous vehicles were driven along these designed roads to obtain driving data, including position, speed, and steering angle. The lateral deviation from the lane center was calculated for each lane by measuring the distance between the front and rear wheels of the vehicle and the lane centerline. This approach allows for the analysis of lane-specific deviation characteristics under different speeds and curve radii, thus enabling a quantitative assessment of the lateral clearance required for autonomous-vehicle operation. Lateral deviation increased when vehicles entered or exited curves, particularly in outer lanes and at curves with changing turning directions. Passenger cars and heavy vehicles showed decreasing deviations within curves, whereas the deviations varied in straight sections. The lateral clearance increased with the design speed for passenger cars, whereas heavy vehicles generally exhibited limited clearance owing to their larger size and mirror widths, with slight increases above 100 km/h. Autonomous vehicles maintained lane centers outside curve entries and exit sections, thus indicating that variable lane widths can be safely implemented. The existing design standards based on human driving may be adapted for autonomous vehicles, thus enabling more efficient roadway use while maintaining stability.
4,000원
20.
2025.12
구독 인증기관 무료, 개인회원 유료
This study develops a post-value for money (post-VfM) evaluation model for public–private partnership (PPP) road projects in Korea. Following the abolition of the minimum revenue guarantee system, the demand risk was transferred to the private sector, thus necessitating an unbiased and data-driven assessment under the new adjusted build-transfer-operate (BTO-a) framework. The proposed model extends the existing ex-ante VfM analysis by incorporating actual operational data and estimating government payments for both public-sector comparator and private finance initiative alternatives on a lifecycle cost basis. Using an actual BTO project restructured as BTO-a, the simulation shows that the post-VfM ratio increases from 23.5% to 37.9%, thus confirming fiscal efficiency and balanced risk sharing. This model enables feedback between planning and operation, supports transparent policy evaluation, and provides a foundation for sustainable PPP governance in future infrastructure projects.
4,000원
1
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