간행물
한국도로학회논문집 KCI 등재 International journal of highway engineering
- 발행기관 한국도로학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1738-7159 (Print)2287-3678 (Online)
- 수록기간 1999 ~ 2024
- 주제분류 공학 > 토목공학 공학 분류의 다른 간행물
- 십진분류KDC 534DDC 625
권호리스트/논문검색
제25권 제2호 (2023년 4월) 11건
1.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : In this paper, problems and improvements in pavement marking standards are proposed as a result of the analysis of domestic/foreign standards and field data.
METHODS : In this study, the US FHWA and all state standards were analyzed and domestic pavement marking standards were compared and analyzed. In addition, national highway marking test data, namely the Yeoncheon Test-Bed data, and data from Hawkins et al. (2015) were analyzed. Based on this, problems and improvements in the Korean pavement marking standards are proposed.
RESULTS : As a result of literature and field data analysis, various problems were found in the Road Traffic Act and National Police Agency manual. In this standard, there is no definition of Qd; the RD reference value is set too low; and the RW and RR reference values are difficult to be considered reasonable values.
CONCLUSIONS : There is an aspect in which the standard items and values of pavement markings are set under some policy judgment. Therefore, it is necessary to properly revise the standards, considering technical and economic aspects.
4,200원
2.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : For most local governments, including that of Gangwon-do, the establishment of an organized pavement management system is insufficient, resulting in problems such as inefficient distribution and use of maintenance budgets for deteriorated road pavements. In this study, we aimed to contribute to the establishment of a more reasonable road maintenance strategy by developing a model for predicting the annual international roughness index (IRI) change for national highway asphalt pavements in Gangwon-do based on big data analysis.
METHODS : Data on independent and dependent variables used for model development were collected. The collected data were subjected to exploratory data analysis (EDA) and data preprocessing. Independent variable candidates were selected to reduce multicollinearity through correlation analysis and specific conditions. A final model was selected, and sensitivity analysis was performed.
RESULTS : The final model that predicts annual IRI change uses independent variables such as annual temperature range, minimum temperature, freeze-thaw days, IRI, surface distress (SD), and freezing days. The sensitivity analysis confirmed that the annual IRI change was affected in the order of annual temperature range, minimum temperature, freeze-thaw days, IRI, SD, and freezing days.
CONCLUSIONS : Road maintenance can be performed rationally by predicting future pavement conditions using the model developed in this study. The accuracy of the prediction model can be improved if additional data, such as material properties and pavement thickness, are obtained in future studies.
4,300원
3.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : Advancements in science and technology caused by industrialization have led to an increase in particulate matter emissions and, consequently, severity of air pollution. Nitrogen oxide (NOx), which accounts for 58% of road transport pollutants, adversely affects both human health and the environment. A test-bed was constructed to determine NOx removal efficiency at the roadside. TiO2, a material used to reduce particulate matter, was used to remove NOx. It was applied to a vertical concrete structure using the dynamic pressurized penetration TiO2 fixation method, which can be easily applied to vertical concrete structures. This study was conducted to evaluate the NOx removal efficiency of the dynamic pressurized-penetration TiO2 fixation method in a test-bed under real roadside conditions.
METHODS : A test-bed was constructed in order to determine the NOx removal efficiency using the dynamic pressurized penetration TiO2 fixation method on the roadside. The dynamic pressurized-penetration TiO2 fixation method was applied by installing a vertical concrete structure. NOx was injected into the test-bed using an exhaust gas generator. By installing a shading screen, the photocatalytic reaction of TiO2 was suppressed to a maximum concentration of 1000 ppb along the roadside. The removal efficiency was evaluated by measuring NOx concentrations. In addition, illuminance was measured using an illuminance meter.
RESULTS : From the results of the analysis of the NOx removal efficiency in the test-bed which the dynamic pressurized type TiO2 fixation method was applied to, an average removal efficiency ranging from 18% to 40% was achieved, depending on the illuminance. Similarly, according to the results of the evaluation of the NO removal efficiency, an average of removal efficiency ranging from 20% to 62% was achieved. Thus, the NOx removal efficiency increased when the illuminance was high.
CONCLUSIONS : From the results of the experiment conducted, the efficiency of NOx removal per unit volume was obtained according to the illuminance of TiO2 concrete along an actual road. Field applicability of the dynamic pressurized-penetration-type TiO2 fixation method to vertical concrete structures along roads was confirmed.
4,000원
4.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study investigated the field applicability of pervious concrete to pavement base courses. Pervious concrete was developed at laboratory level, and the compaction methods, field moisture content, and fundamental properties when the material was constructed in the field were studied.
METHODS : Field-applied pervious concrete was compacted at different levels using a tandem roller, and cores were taken to investigate the compressive strength, infiltration rate, continued porosity, and freeze-thaw resistance. In addition, the optimum field construction and quality control of the moisture content of a batch plant were measured.
RESULTS : The moisture content of pervious concrete has an essential effect on workability and quality control during field test construction. From the test herein, the optimum value at a batch plant was found to be approximately 2.5±0.1%. The compaction level is also a crucial parameter at construction sites because it affects the mechanical and penetration properties. Considering both compressive strength and drainage, the recommended compaction was three times the round trip when a tandem roller was used. The penetration coefficient was 0.88 cm/sec when applying three times the round trip of the tandem roller. The freezing and thawing weight loss rates of the applied pervious concrete satisfied the required condition of 14% or less, regardless the compaction level.
CONCLUSIONS : With the suggested mixed proportions of pervious concrete, the recommended compaction was three times the round trip of a tandem roller and a moisture content of approximately 2.5±0.1% from a batch plant. When these conditions were satisfied, the mechanical and drainage properties satisfied the required criteria.
4,000원
5.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study proposes brief guidelines for traffic engineers in the field to refer to when operating tram priority signals based on the "early green" and "green extension" methods.
METHODS : A set of VISSIM simulation analyses was conducted considering various traffic and control conditions in a hypothetical corridor consisting of two signalized intersections. The traffic conditions were varied at five different levels. The control conditions were varied at twenty-five levels by changing the tram priority traffic signal control parameters, i.e., the early green unit time and green extension unit time. A total of 125 simulation runs were from these combinations. A set of optimal signal timings for ordinary non-tram vehicles was prepared with TRANSYT-7F and implemented for the simulation. A tram priority signal control module based on VISVAP was exclusively developed for this study.
RESULTS : As expected, no specific trend was found in the relationship between the two tram priority control parameters (early green time and green extension time). However, a trend was observed when assuming that the early green and green extension operations were mutually exclusive. Specifically, an inverse trend appeared between the tram priority control parameter values and level of congestion according to the performance measure (average network delay).
CONCLUSIONS : For the early green control parameters, it is better to provide six seconds when undersaturated and four seconds when near-saturated. For the green extension control parameter, four seconds is suitable.
4,000원
6.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : The purposes of this study are to identify appropriate numbers of drivers for different time periods by analyzing the service times of the Special Transportation System and to shorten the waiting time to within 15 minutes.
METHODS : In this study, the service time is divided into the call connection time (At), dispatch time after reception (Bt), vehicle arrival time after dispatch (Ct), and vehicle boarding time (Dt), and the annual average value for each time zone is calculated by analyzing the dispatch system database. Furthermore, the number of drivers working in each time period is extracted and the appropriate number of drivers for ensuring the dispatch waiting time remains within 15 minutes is determined.
RESULTS : It is more accurate to interpret the decrease in dispatches during lunchtime as a decrease in the number of operational vehicles owing to the drivers' lunchtimes rather than a decrease in demand. During lunchtime (as in previous studies) the number of operations decreases, but the average dispatch time (Bt) greatly increases to 22:42; thus, it cannot be seen as a decrease in dispatch demand. The number of operations during lunchtime is proportional to the number of drivers on duty. The number of drivers on duty is inversely proportional to the average dispatch time. If the number of drivers is increased by 11.6%, the average waiting time can be reduced to within 15 minutes.
CONCLUSIONS : To resolve delayed call connection issues, we will introduce an artificial intelligence (AI) call center. During the hours of 7 PM to 6 AM, calls will mainly be handled by AI and the counseling personnel will switch to daytime work. We will also increase the number of drivers by 11.6% to ensure that the dispatch time does not exceed an average of 15 minutes after receiving a call. In particular, we will generate the work schedule such that more than 131 drivers work in the 12:00 to 13:00 hours during lunch time to improve the situation where users have to wait for a long time. To do this, we will overlap the work hours for 2 hours in Jeonju and 1 hour in other cities and counties. We have to increase the number of night shift workers from seven to 15 so that all cities and counties can operate vehicles 24 hours a day, 365 days a year.
4,300원
7.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : Traffic congestion on freeway generally occurs when the traffic volume exceeds the road capacity. Most traffic manuals *such as the Korean Highway Capacity Manual) present the highway capacity as approximately 2,000 units/hour. However, in the real world, freeway congestion occurs for various reasons, including unusual driver behaviors, physical road limitations, and large traffic volumes. Thus, the flow rate at a traffic breakdown can have a wide range of volumes. Therefore, using 5-min volume and speed data from the field, this study explores the stochastic features of traffic breakdowns on major urban freeways in Seoul.
METHODS : First, a breakdown point is defined by applying a wavelet transform to identify the sharp drop in the speed data near freeway bottlenecks. Second, based on the flow rate at and before a breakpoint, a survival analysis is performed to construct the probability distributions of the traffic breakdown. Log-rank tests are also conducted to verify the similarities of the distributions between freeways.
RESULTS : The analysis results confirm the stochastic features of the urban freeways in Seoul. Specifically, the freeways have typical S-shaped distributions of breakdown probabilities. However, the distributions rise steeply (exceeding a 50% of breakdown probability) at flow rates of 1,150 vphpl to 1,700 vphpl; this is lower than the general expectation.
CONCLUSIONS : The statistical differences in the probability distributions for freeways indicates that applying a general standard to every urban highway could raise problems. This study has a limitation in identifying the specific causes of traffic congestion owing to the by physical relationships between individual vehicles. An investigation if vehicle trajectory data should be conducted to examine these aspects in further detail.
4,000원
8.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study proposes an index for analyzing mobility based on smartcard and taxi data to evaluate imbalances in public transit.
METHODS : The proposed mobility index is calculated based on the difference between the mobility indexes of public transit and taxis using the variables of the in-vehicle time, waiting time, and driving ratio. For a more detailed analysis, the distances are divided into short distances, medium distances, and long distances.
RESULTS : Public transit mobility indexes are generally evenly distributed, but the taxi mobility indexes are located in the largest legend. When comparing the respective mobilities of public transit and taxis, many areas with a high mobility of taxis (similar to the distribution) exist, especially in the outskirts such as Dobong-gu, Nowon-gu, Gangdong-gu, Guro-gu, Geumcheon-gu, and Eunpyeong-gu. On average, the mobility of public transit according to the distance is smaller in a short distance and higher in a long distance.
CONCLUSIONS : The results demonstrate the use of the proposed index for analyzing the basic statuses of complementary indexes for evaluating public transit imbalances. In the future, more detailed results (including socioeconomic variables corresponding to the grid areas) should be studied to identify the impacts of the mobility index.
4,000원
9.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : The main purpose of this study is to identify directions for improvement of triangular islands installation warrants through analysis of the characteristics of crashes and severity with and without triangular islands on intersections.
METHODS : The data was collected by referring to the literature and analyzed using statistical analysis tools. First, an independence test analyzed whether statistically significant differences existed between crashes depending on the installation of triangular islands. As a result of the analysis, individual prediction models were developed for cases with significant differences. In addition, each crash factor was derived by comparison with each model.
RESULTS : Significant differences appeared in the "crash frequency of serious or fatal" and "crash severity" owing to the installation of triangular islands. As a result of comparing crash factors through the individual models, it was derived that the differences were dependent on the installation of the triangular islands.
CONCLUSIONS : As a result of reviewing previous studies, it is found that improving the installation warrants of triangular islands is reasonable. Through this study, the need to consider the volume and composition ratio of right-turn vehicles when installing a triangular island was also derived; these results also need to be referred to when improving the triangular island installation warrants.
4,000원
10.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study analyzes the effectiveness of different types of children's safety devices in a school zone. The analysis targets are yellow carpet type A (installed up to the floor and wall) and yellow carpet type B (installed only on the floor).
METHODS : Based on field data collected at a school zone in Seoul, statistical tests were conducted to compare three different pairs of data: (1) none vs. yellow carpet type A, (2) none vs. yellow carpet type B, and (3) yellow carpet types A and B. The test employed two different measures: (1) the level of drivers’ eye attention and (2) the level of the vehicle deceleration rate. The study utilized software named "Visual Attention Software" to quantify the level of drivers’ eye attention at the location where children pedestrians were waiting for a green signal. It also utilized the Vegas (pro 17) image processing software to reduce the cruising speed data frame-by-frame from the video streaming data. The image data used in this study were collected with (1) camcorders attached to a test vehicle and (2) a drone aerial imaging technique.
RESULTS : It was found that the level of the drivers’ eye attention level improved in the daytime when either of yellow carpet types A and B was placed; moreover, the safety enhancement effects were statistically identical. However, in nighttime, the measures only improved when the yellow carpet type A was placed. It was learned that yellow carpet type A provides significant safety effects according to both measures, i.e., the level of drivers’ eye attention and cruising speed.
CONCLUSIONS : The test results suggest that the yellow carpet type A should be installed in school zones to maximize the safety effects of yellow carpets.
4,200원
11.
2023.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study empirically analyzes the determinants of fatal accidents based on raw data on traffic accidents occurring in Chungnam in 2020.
METHODS : Regression models based on theoretical arguments for fatal traffic accidents are estimated using a binomial logit model.
RESULTS : The prediction model for fatal accidents is affected by the degree of urbanization of the region, month and day of the accident, type of accident, and type of law violation. In addition, speeding or illegal U-turns among law violations appear more likely to result in fatal accidents. The road surface conditions at the time of the accident do not show a significant difference in the probability of fatality among traffic accidents. However, the probability of a fatal accident is rather lower in case of a snowy road; this is plausible, as drivers tend to drive more carefully in bad weather conditions.
CONCLUSIONS : Among traffic accidents, fatal accidents appear to be affected by the time and place of the accident, type of accident, and weather conditions at the time of the accident. These analysis results suggest policy implications for reducing fatal accidents and can be used as a basis for establishing related policies.
4,000원
