• Journal of Korean Society of Transportation
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• v.20 no.4
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• pp.163-175
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• 2002

Fatalities from traffic accidents constitute one of the major health issues as well as safety ones in Korea. It has been reported that traffic accident is affected by the combined effects of road. vehicle. and human factors. Over the past few decades, a number of studies have been conducted to find the impact of road geometric factors on traffic safety. The purpose of this study is to investigate the effect of road geometric factors on traffic safety on Korean expressways. Detailed geometric design data were available from Korea Highway Corporation. Five-year traffic accident data on Honam expressway were collected and analyzed. It was found that following geometric factors influence traffic safety on expressways : radius of curve, curve length, and length of straight section. Furthermore, the existence of I.C. turned out to have a significant impact on traffic safety level. Based on the data analysis several multiple regression forms that relate traffic accident frequencies and geometric factors on expressways are developed.

• Proceedings of the KOR-KST Conference
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• 1998.10a
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• pp.285-294
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• 1998

기존 도로시설을 최대로 이용하고 교통의 흐름을 질적으로 향상시키기 위해서는 과포화 상태를 고려한 교통시설운영방법을 개선할 필요가 있다. 속도-교통량관계는 교통시설운영의 평가와 서비스수준 산정을 위한 주요 판단기준이 된다. 본 논문에서는 경부고속도로 종점부 구간의 현장조사를 통해 과포화상태의 속도-교통량 관계를 조사 분석하였고 그 결과 다음 몇 가지 결론을 얻을 수 있었다. 첫째, 한국도로용량편람을 비롯한 우리 나라 연구결과는 일반적으로 50km/hr 일 때 용량상태가 나타난다고 알려져 있으나 본 조사결과에 의하면 약 85km/hr 정도에서 용량상태가 발생함을 관측할 수 있었다. 둘째, 과포화구간에서 속도에 따른 통과교통량 증감추이는 대기행렬 증가시 급격한 속도-교통량의 감소가 있는 반면에 대기행렬해소시 속도-교통량의 증가는 완만하게 회복됨을 보였다. 셋째, Ontario 고속도로의 경우와 본 조사연구결과는 비교해본 결과 과포화시 한국의 경우 미국과 동일한 통행속도에서 더 많은 교통량이 통행하는 것으로 확인되었다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.52-62
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• 2013

Design Hourly Factor(DHF) is defined as the ratio of design hourly volume(DHV) to Average Annual Daily Traffic(AADT). Generally DHV used the 30th rank hourly volume. But this case DHV is affected by holiday volumes so the road is at risk for overdesigning. Computing K factor is available for counting 8,760 hour traffic volume, but it is impossible except permanent traffic counts. This study applied three method to make DHF, using 30th rank hourly volume to make DHF(method 1), using peak hour volume to make DHF(method 2). Another way to make DHF, rank hourly volumes ordered descending connect a curve smoothly to find the point which changes drastic(method 3). That point is design hour, thus design hourly factor is able to be computed. In addition road classified 3 type for national highway using factor analysis and cluster analysis, so we can analyze the characteristic of DHF by road type. DHF which was used method 1 is the largest at any other method. There is no difference in DHF by road type at method 2. This result shows for this reason because peak hour is hard to describe the characteristic of hourly volume change. DHF which was used method 3 is similar to HCM except recreation road but 118th rank hourly volume is appropriate.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.69-82
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• 2004

Urbanization of Korea reaches up to 90% in the year 2003. What that means is that 90% of population live in the city areas. This phenomenon emphasizes importances of urban streets where people feel accessibility and level of environmental amenity, enjoy recreational activity, and live for a life. However, the current Korean manual for designing road is not enough to accomodate various activities of urban streets since its target is basically rural roads. This study proposes the necessity of a new design manual of urban streets via analyzing the practices of the development countries, and aims to recommend what should be prepared and how those are defined for developing a design manual of urban streets in Korea. It is inevitable that the design manual of urban streets be based on the flexibility and diversity. The manual should be made through consensus among the related stakeholders such as designers, residents and officials. And it also should reflect the characteristics of each city. It is somehow true that without the manual, designing of urban streets can be done although it is not fully acceptable. This does not mean that the necessity of the manual can be ignored. Rather, we should remember that the related stakeholders may not want to reveal what are hidden in developing the design manual of urban streets. What are hidden is that developing the design manual of urban streets is difficult problem to solve. It is a wish that this study triggers the on-going research and interests on developing the design manual of urban streets.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.72-77
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• 2002

The development of a Pay Adjustment (PA) procedure for implementing Performance-related Specifications (PRS) is known to be a difficult task faced by most State Highway Agencies (SHAs) due to the difficulty in such areas as selecting pay factor items, modeling the relationship between stochastic variability of pay factor items and pavement performance, and determining an overall lot pay adjustment. This led to the need for an effective way of developing a scientific pay adjustment procedure by incorporating Life Cycle Cost Analysis (LCCA) embedded Monte Carlo approach. In this work, we propose a prototype system to determine a PA specifically using the data in the pavement management information systems at Wisconsin Department of Transportation (WisDOT) as an exemplary to other SHAs. It is believed that the PRS methodology demonstrated in this study can be used in real projects by incorporating the more accurate and reliable performance prediction models and LCC model.

• Journal of Korean Society of Transportation
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• v.28 no.3
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• pp.131-143
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• 2010

This study has aimed to develop accident modification factor(AMF) for rural two-lane roadway segments. Accident Modification Factor is a coefficient to assess roadway safety as reflecting characteristics of homogeneous roadway. It estimates accident frequency of roadway segments with developed base model and exposure. We found on items of such factors as crosswalk, driveway density, topography characteristic, land use and median through statistical models and literature review. To develop accident modification factors, we used statistical model methods and analyses of applicability and expert judgement method were practiced to validate it. Although expert judgement for land use item was questionable, most items were rated acceptable. Result of comparative analysis revealed crash frequencies of IHSDM and KHSEM were most similar with actual. However, accident distribution of KHSEM was more proper than IHSDM. Also overall estimated values of RSDS were found to be overestimated.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.41-53
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• 2010

Traffic safety assessment is often accomplished by analyzing the number of crashes occurring in some geographic space over certain specific time duration. In this paper, we introduce a procedure that can efficiently analyze spatial and temporal changes in traffic crashes before-and-after implementation of a certain traffic controlling measure. For the analysis, crash frequency data before-and-after closing a major highway around St. Louis in Missouri was collected through Transportation Management System(TMS) database that is maintained by Missouri Department of Transportation (MoDOT). In order to identify any spatial and temporal pattern in crashes, each crash is pinpointed on a map using the dynamic segmentation in GIS. Then, the identified pattern is statistically confirmed using an analysis of variance table. The advantage of this approach is to easily assess spatial and temporal trend of crashes that are not readily attainable otherwise. The results from this study can possibly be applied in enhancing the highway safety assessment procedure. This paper also makes several suggestions for future development of a comprehensive transportation data system in Korea which is similar to MoDOT's TMS database.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2D
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• pp.251-258
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• 2006

This study is to develop an estimation method of freeway design capacity through the analysis of time headway distribution in continuum flow. Traffic flow-speed diagram and time headway distribution plotted from individual vehicle data shows: a) a road capacity is not deterministic but stochastic, b) time headway distribution for each vehicle speed group follows pearson type V distribution. The freeway design capacity estimation model is developed by determining a minimum time headway for capacity with stochastic method. The estimated capacity values for each design speed are lower when design speed ${\leq}80km/h$, and higher when design speed ${\geq}106km/h$ in comparison with HCM(2000)'s values. In addition, The distinguish difference is that this model leads flexible application in planning level by defining the capacity as stochastic distribution. In detail, this model could prevent a disutility to add a lane for only one excess demand in a road planning level.

• Journal of Auto-vehicle Safety Association
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• v.5 no.1
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• pp.31-36
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• 2013

For the robust passenger NCAP 5star and the stable neck injury performance, a new concept of passenger airbag has been required strongly. Especially, the deployment stability and the vent hole control technology of the passenger airbag should be improved. According to these requirements, the deployment stability technique has been studied and the 'Active Vent' technology has been developed. As a result, these technologies have led to achieve the robust NCAP rating and are applied to the production vehicles.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.287-293
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• 2008

Density is used as the measure of effectiveness within the ramp junction influence area suggested in the KHCM 2005 in the LOS analysis of the ramp junction, and also density predictive models suggested in the KHCM 2005 is constructed based on the expressway with the speed limit of 100km/h or 110km/h in Korea. So, the density predictive models suggested in the KHCM 2005 are needed to verify if the models could be applied to the urban freeway with the speed limit of 80km/h or less, because the speed limits on most of the urban freeways in Korea are 80km/h or less. The purpose in this study is to construct and verify the appropriate density predictive model within the on-ramp merge influence area of the urban freeway by comparing with the USHCM 2000 and KHCM 2005 models.