• Journal of Korean Society of Transportation
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• v.3 no.1
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• pp.86-93
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• 1985

1965년에 출판된 고속도로용량교범(Highway Capacity Manual)은 고속도로, 도시 및 지방도로의 용량과 서비스수준을 판단하는데 기본서 역할을 해왔다. 도시내 신호등이 있는 교차로의 서비스수준은 빈하율(load factor) 개념을 이용하여 산정해 왔다. 그러나 푸른신호 주기동안 차량의 교차로이용도를 기준으로 하는 빈하율 개념은 서비스 수준의 측정치로서 한계가 있고 또 그동안 신호체계가 많이 개선되었고 운전자의 통행행태가 크게 변화하여 1970년대 중반부터 한계통행분석법(Critical Movement Analysis)과 차량의 교차로지체시간 측정법(Intersection Delay)등과 같은 새로운 기법이 소개되었다. 본 논문은 최근에 많이 이 용되고 있는 교차로지체시간측정법의 유용성을 검증하기 위해 15개 교차로의 차량통행량을 기준으로 하여 V/C비를 계산하는 한계통행분석법에 의한 측정치와 비교, 분석하였다. 그 결 과 교차로의 서비스수준을 측정하는데 양자의 방법에 의한 측정치가 크게 다르지 않음을 발 견하였다. 즉 도시내 신호등이 있는 교차로시설을 개선하기 위해 대략적인 교차로 서비스수 준을 측정할 경우 조사인원 및 비용이 많이 소요되는 한계통행분석법보다 조사가 간편하고 비용이 적게 드는 교차로지체시간측정법이 유용함을 밝혔다.

• Journal of Korean Society of Transportation
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• v.14 no.4
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• pp.155-178
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• 1996

신호교차로 서비스수준은, 객관적으로 측정 할 수 있는 여러 가지 기준에 의해 결정될 수 있다. 예를 들면, 지체시간(Delay), 교통사고수(Number of Accident), 교통사고율(Accident Rate), 충돌수(Traffic Conflict), 그리고 교통사고에 노출된 차량수(Exposure)등이다. 지금까지는 1985 Highway Capacity Manual(HCM)에서 소개된 지체시간에 의한 서비스수준 결정방법이 널리 사용되어 왔다. 본 논문에서는 1985 HCM 방법의 중용성과 유용성에 대해 논하지 않고, 교통안전(Safety)에 의한 신호교차로 서비스수준 결정방법을 제시하였다. 교차로의 위험도(Degree of Intersection Hazard)를 예측하기 위해, 교통사고빈도 수가 가장 높은 두가지 교통사고 유형, 즉 좌회전추돌(Left-Tum)과 후미추돌(Rear-End) 예측 모형이 개발되었다. 여기서 첫째, 좌회전추돌 위험도를 예측하기 위하여 음지수 분포(Negative-Exponential Distribution)를 이용한 확률적 모형이 개발되었다. 둘째, 후미추돌 위험도를 예측하기 위하여 연속류 모형(Continuum Model)을 이용한 거시적 모형이 개발되었다. 개발된 두가지 모형을 이용하여 신호교차로 안전도를 예측하였으며 교차로 서비스수준이 안전도에 의해 결정되었다. 본 논문에서 제시된 교통안전에 의한 신호교차로 서비스수준 결정방법은 연동교차로를 제외한 독립교차로에만 적용이 된다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.3
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• pp.13-22
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• 2012

Estimating directional design hourly volume (DDHV) is an important aspect of traffic or road engineering practice. DDHV on highway without permanent traffic counters (PTCs) is usually determined by the annual average daily traffic (AADT) being multiplied by the ratio of DHV to AADT (K factor) and the directional split ratio (D factor) recommended by Korea highway capacity manual (KHCM). However, about the validity of this method has not been clearly proven. The main intent of this study is to develop more accurate and efficient DDHV estimation models for national highway in Korea. DDHV characteristics are investigated using the data from permanent traffic counters (PTCs) on national highways in Korea. A linear relationship between DDHV and AADT was identified. So DDHV estimation models using AADT were developed. The results show that the proposed models outperform the KHCM method with the mean absolute percentage errors (MAPE).

• Journal of Navigation and Port Research
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• v.31 no.1 s.117
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• pp.107-113
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• 2007

This research addressed the problem of describing how the operating characteristics of passenger car and large vehicle differ qualitatively and quantitatively through the analysis of field survey data. A formulation that estimates passenger car equivalents used in this paper is derived by microscopic headway method. Regression analysis was used to focus on the effect of vehicle type on intervehicular spacings and the modeling technique for the statistical analysis was detailed.

• Journal of Environmental Policy
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• v.11 no.3
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• pp.49-65
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• 2012

Road traffic noise is closely related to road traffic environment, including traffic volumes by type and travel speed. In this study, we stated some issues and analyzed the relationships between road traffic noise and traffic flow characteristics. First, in attempt to find the answer to the question "When does the loudest traffic noise occur?" we reviewed the issue in the terms of traffic flow. As a result of analyzing level of service through Korea Highway Traffic Noise model, the actual maximum noise occurred in level of service D rather than level of service E, on the capacity state. It shows that maximum noise would be most likely to occur right before and after the peak hours. Second, this paper was looking for the method of a more easy and accurate traffic speed estimation to predict traffic noise. This paper proposed sketch planning techniques of speed-volume curve by level of service on Korea Highway Capacity Manual. As a result of trend line modeling, it was judged that quadratic form is a suitable function, and coefficient of determination ($R^2$) was higher than 0.96, respectively.

• Journal of Korean Society of Transportation
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• v.22 no.3 s.74
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• pp.159-166
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• 2004

The capacity concept presented in the Highway Capacity Manual is for steady-state traffic flow assuming that there is no restriction in downstream flowing, which is traditionally used for planning, design, and operational analyses. In the congested traffic condition, the control objective should be to keep the congested regime from growing and to recover the normal traffic condition as soon as possible. In this control case, it is important to predict the spatial-temporal pattern of congestion evolution or dissipation and to estimate the throughput reduction according to the spatial-temporal pattern. In this context, the new concept of dynamic capacity for managing congested traffic is developed in terms of spatial-temporal evolution of downstream traffic congestion and in view of the 'input' concept assuming that flow is restricted by downstream condition rather than the 'output' concept assuming that there is no restriction in downstream flowing (e.g. the mean queue discharge flow rate). This new capacity is defined as the Maximum Sustainable Throughput that is determined based on the spatial-temporal evolution pattern of downstream congestion. And the spatial-temporal evolution pattern is estimated using the Newell's simplified q-k model.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.111-121
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• 2001

Rockfall protection fences are used for diminishing rockfall damage in roads side slopes. In order to install the fences in effective way, the conditions of rock slopes and total predicted impact energy of fa11ing rock should be considered. However, the fences have been constructed without any consideration for lithology, height and slope angle of rock slope in Korea. In addition, the information about the performance of the protection fences, which should be evaluated by in-situ test or laboratory test in order to check out the practical use in the field, is not available. Therefore, in design manual for the rockfall protection fence, the specific details for the installation of this type of fence are not provided yet. The full sized rockfall in situ test was carried out for the calculation of falling energy of rock and the evaluation of the maximum energy absorbing capacity of fence. For this test, the rock slopes whose heights are about 20 m and dip angle of 65 degree, have been chosen. This is because those geometries are mean height and slope angle of most road cut slopes along Korean national highway. Based on the preliminary simulation procedure, four different sizes of concrete ball (0.7, 1.3, 2.3 and 4.3 ton) were prepared and flour different types of protection fence were constructed. The results of this test provide information about the maximum energy absorbing capacity of the fence, kinetic energy of rockfall and restitution coefficient, and these results can be utilized in the establishment of rockfall fence design and construction manual.

• Journal of Korean Society of Transportation
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• v.28 no.5
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• pp.7-15
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• 2010

The walkway level of service (LOS) is conceptualized using pedestrian flow rate, speed, and density according to the Korean Highway Capacity Manual (KHCM). However, as it is based on the data of commuters at peak hours, it needs to be reevaluated considering various trip purposes and a pleasant pedestrian environment. Thus, the authors aimed to investigate and analyze the characteristics of each group: pedestrians during the peak hour and those during the non-peak hour. Then they were verified statistically for the walkway evaluation criteria. In this study, the authors investigated pedestrian speed and flow in a complex transit center walkway with diverse trip purposes by peak and non-peak hour. Then the authors statistically verified the differences between the groups. A model was built for estimating pedestrian density by speed and flow; it was used to calculate the walkway capacity (67.3p/m/m) corresponding to LOS E. The authors established new criteria for LOS, applying the LOS from the HCM. These standards can then be used as the design standards for pedestrian walkways.

• International Journal of Highway Engineering
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• v.16 no.5
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• pp.109-119
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• 2014

PURPOSES : The control delay in seconds per vehicle is the most important traffic operational index to evaluate the level of service of signalized intersections. Thus, it is very critical to calculate accurate control delay because it is used as a basic quantitative evidence for decision makings regarding to investments on traffic facilities. The control delay consists of time-in-queue delay, acceleration delay, and deceleration delay so that it is technically difficult to directly measure it from fields. Thus, diverse analysis tools, including CORSIM, SYNCHRO, T7F, VISTRO, etc. have been utilized so far. However, each analysis tool may use a unique methodology in calculating control delays. Therefore, the estimated values of control delays may be different by the selection of an analysis tool, which has provided difficulties to traffic engineers in making solid judgments. METHODS : This study was initiated to verify the feasibility of diverse analysis tools, including HCM methodology, CORSIM, SYNCHRO, T7F, VISTRO, in calculating control delays by comparing estimated control delays with that measured from a field. RESULTS : As a result, the selected tools produced quite different values of control delay. In addition, the control delay value estimated using a calibrated CORSIM model was closest to that measured from the field. CONCLUSIONS : First, through the in-depth experiment, it was explicitly verified that the estimated values of control delay may depend on the selection of an analysis tool. Second, among the diverse tools, the value of control delay estimated using the calibrated microscopic traffic simulation model was most close to that measured from the field. Conclusively, analysts should take into account the variability of control delay values according to the selection of a tool in the case of signalized intersection analysis.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.75-84
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• 2012

PURPOSES : This paper aims to improve the evaluation method of the Level of Service(LOS) for urban streets presented by the current Korean Highway Capacity Manual(KHCM) and suggest its utilization plan as a part of the methods to evaluate the sustainability of a transportation policy. METHODS : This paper carried out a research in 3 steps to develop a new evaluation method. First of all, this paper reviewed the previous studies related to the LOS of urban streets and the socially requested items for a sustainable transportation system. Then this paper derived an index and weight through expert questions to select an evaluation index. Lastly, this paper compared the results according to the existing evaluation methods with the new evaluation methods through case studies. This paper used an Analytic Hierarchy Process(AHP) for importance analysis and weight selection between new evaluation items and indices, and applied a Grey System Theory(GST) for a synthetic and integrated evaluation between the selected evaluation indices. RESULTS : As a result of evaluating the LOS according to the existing evaluation methods and the integrated evaluation methods using a GST through case studies, it was analyzed that new methods' results are less than or equal to the existing evaluation methods; and as a result of applying a weight between evaluation indices according to AHP, it was noticed that the total score seems to rise more when the LOS in the existing evaluation is calculated lower. It was analyzed that the LOS calculated by reflecting the newly established evaluation items and the importance between indices in this study has difference from the LOS of the existing urban streets. CONCLUSIONS : It is expected that this evaluation method can diagnose the current conditions when establishing a future sustainable traffic system and can be used for the measurement of the sustainability effects of the improvement plans and so on.