• International Journal of Highway Engineering
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• v.14 no.4
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• pp.93-101
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• 2012

PURPOSES : Adverse weather conditions such as heavy rain, heavy snowfall, and thick fog and so on have highly affect on the change in traffic conditions on the road. In particular, heavy snowfall causes capacity reduction as well as crash occurrence. This study investigated the effects of snowfall on speed on a freeway. METHODS : Vehicle detection systems data were matched with corresponding weather station data by regression analysis. RESULTS : The results show that the travel speed is reduced by 6.7% under little snowfall and by 12.8% under heavy snowfall. Regarding the speed variation, 8.7% and 114.7% increases are observed under little snowfall and heavy snowfall, respectively. It is also found that 1 cm increase in snowfall leads to 0.4% decrease in travel speed. In addition, the travel speed increases by 0.4% when the temperature increases by $1^{\circ}C$. CONCLUSIONS : It is expected that the outcome of this study will be useful in establishing more effective strategies for winter operations and road maintenance in practice.

• International Journal of Highway Engineering
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• v.19 no.3
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• pp.45-55
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• 2017

PURPOSES: The objective of this study is to estimate required minimum spacing between Freeway IC for high-speed roadways. METHODS : Since high-speed roadways with over 140 km/h design speed do not exist in Korea, VISSIM Simulation Program was used for analysis. Acceleration noise and conflicts were selected for Evaluation Index. Standard deviation size for acceleration and deceleration was calculated by VISSIM to estimate acceleration noise. Conflicts were produced in areas between Freeway IC with SSAM. RESULTS : As a result, required minimum spacing was 6 km for acceleration noise analysis, while 5 km was deducted for conflict analysis. For Model Evaluation, with SAS, conflicts did not show much difference in 5~6 km area by 90% confidence interval. CONCLUSIONS : For acceleration noise, results showed lacking in its discrimination between index per Minimum Spacing. However, conflicts were valid in difference; required minimum spacing was 5 km by validation result.

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.161-171
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• 2016

OBJECTIVES : Many roadway departure crashes on the freeway interchange are due to the running speed being greater than the design speed. This study aims to ensure a safe and pleasant driving experience for the driver by increasing the superelevation based on the running speed on the highway interchange ramp. METHODS : The mean running speed for each type of ramp is calculated on site survey more than 10 interchanges. Using the mean running speed, we calculated the superelevation and the side friction using the method given in "A Policy on Geometric Design of Highways and Street" (Pages 145-166, 2001). Then, we applied the modified method to the superelevation range. Finally, we ensured safety using the Degree of Safety that is proven by the centrifugal acceleration ratio as suggested by Joseph Craus (1978). RESULTS : The mean running speeds are 50 km/h and 65 km/h when the design speeds are 40 km/h and 50 km/h, respectively. After the application of the new method used in this study, the superelevation will be increased by 9.0% and 10.0% when the mean running speeds are 50 km/h and 65 km/h, respectively. CONCLUSIONS : A higher superelevation can give the driver a more comfortable and safe driving environment. However, the driver needs to be aware of snow and low-temperature conditions.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.2
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• pp.19-27
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• 2008

Ecosystem fragmentation by human intervention breaks down the biosphere habitat. Wildlife corridors connect biosphere habitats to maintain ecosystem continuity and provide animals with connecting routes. In Korea, there are 17 existing wildlife corridors on highways (as of December, 2006. Korea Freeway Corporation). There are 24 highway routes, 2,923km of highway(as of December, 2004. Korea Freeway Corporation). However, wildlife corridors are not enough and roadkill increases every year, so we need to construct additional wildlife corridors on highways. This study proposes a new approach to the location of wildlife corridors on highways, using a comprehensive analysis method for main location elements, and applies it to a study area. First, it examines traditional approaches to location of wildlife corridors through literature review and field study to analyze the present conditions of existing wildlife corridors. Then, it developes a comprehensive analysis method for the location of wildlife corridors. (1) Field investigation : investigate planting, water bodies and so on. (2) Roadkill analysis : roadkill counts, locations, time, and so on. (3) Monitoring : animal traces were surveyed and sensor cameras were installed to determine target species. (4) Simulation for animal movement : most probable wildlife dispersal was simulated by a computer software. (5) A new comprehensive approach overlays all analysis on a map and determines the location of proposed new wildlife corridors. In conclusion, it proposes an over-bridge type wildlife corridor in Dalnaenae Hill (413-414km from Busan) and an underpass type near the entrance to Gwanhyun temple way (415-416km from Busan). This new approach based on roadkill data, computer simulation of wildlife dispersal, monitoring of animals, and site analysis, may contribute to better location of wildlife corridors on highways.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3D
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• pp.289-294
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• 2010

It is well known that rumble strips contribute to reduce traffic accidents. The present paper provides the reduction effect of traffic accidents under specific highway geometrics after rumble strip installation. Traffic accidents on freeway sections before and after rumble strip installation are compared when conditions of the highway geometric characteristics such as horizontal, vertical geometrics are given. It is shown that rumble strips are effective under highway geometric conditions of down slopes or right curvatures. It is also shown that rumble strips are still effective with shorter length of installation.

• International Journal of Highway Engineering
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• v.20 no.2
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• pp.1-8
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• 2018

PURPOSES : In this study, design elements of rest areas for drowsy drivers are classified and appropriate criteria for each design element are presented. METHODS : By comparing and analyzing the design criteria for rest areas, the most appropriate installation criteria were suggested by considering the driving patterns of rest area users. RESULTS : As a result of the study, elements influencing the design of rest areas for drowsy drivers are suggested such as installation location and installation type. In addition, proper separation distance between resting areas was suggested considering vehicle flow, users' fatigue and physiological needs. Other criteria for rest areas were also suggested. CONCLUSIONS : Proper safety facilities were not installed in rest areas because appropriate criteria were not established. In this study, design elements were derived and installation criteria were designed so that rest areas could be used safely and conveniently.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.699-704
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• 2005

Normally, monetary penalties for breach of agreement will be stipulated in the contract. The contractor parties, who fail to fulfill the agreement, are required to pay the other parties a certain amount or proportion of money as a fine. However, it is worth our study - whether or not the scope of monetary penalty implementation and bases for determination of a fine will cover the losses of social and administrative costs incurred by the interruption of the contract. This research is about the best timing for government to cancel the freeway repair work contracts. Under the goal of the maximum social welfare, the limitation of government spending for the social and administrative costs invoked by interruption of contracts will have to be considered to attain the best timing of contracts' suspension or deferment. According to the factors of social and administrative costs, the best time point is calculated to reduce the loss of the aforesaid costs, which can also be used as theoretical basis for the future road-widening construction at home.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.37-47
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• 2010

This research is aimed at comprehensively evaluating the condition of a road surface of a highway in satisfaction of its users. This research conducted an overall evaluation of a road surface condition by adding qualitative data, or a driver's satisfaction to the existing quantitative elements, whereas the existing research put its focus on a correlation analysis with quantitative factors and qualitative factors through a statistical method. As for an evaluation method, this research conducted an overall evaluation by using Grey System Theory which makes possible an integrated evaluation. The analyzed results make it possible to diagnose the current conditions of each section of object roads and to predict the potentially changeable conditions for the time to come. In addition, these analyzed results could hopefully be applied to the maintenance of freeways through diverse methods. It is hoped that the evaluation of a road surface condition of a highway in satisfaction of its user could be helpful to keeping up the satisfaction of a driver and passenger on the highway by more than a certain level. In addition, the analyzed data on the influence of data value observed by comprehensively evaluating a variety of elements could be used as a secondary means of the decision-making process in relation to road maintenance. On top of that, it could be used as a means of improving road maintenance system and offering the improved driving environment of the highway.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.77-87
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• 2007

Traffic accidents on freeway are occurred by various factors, and driver inattention is one of the most important factors causing traffic accidents. To warn drivers about unexpected dangerous events and diminish driver inattention problems, traffic safety facilities including warning and regulatory traffic signs; delineators; rumble strips are installed. In this study, the traffic safety effect of shoulder rumble sips were investigated using "Comparison Croup (C-G)" method developed by Hauer. Through the analyses, it was found that numbers of run-off-the road crashes were reduced as 2.43 crashes per year after the installation of shoulder rumble strips on the freeway. Based on the analysis results in this study, it was concluded that shoulder rumble strips on the freeway contribute to reduce traffic accidents, especially run-off-the road crashes.

• Journal of Korean Society of Transportation
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• v.17 no.3
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• pp.87-96
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• 1999

It is very important to analyze the capacity of basic freeway section in terms of planning, design, and operation of roads. Capacity, in Korean Highway Capacity Manual was Published in 1992, had been determined by data collected in only 4-lane freeway. But, Korea is continuously planning and constructing multi-lane roads for increasing traffic demand. For this reason, it is necessary to determine the capacity for multi-lane freeways. This study goals are two-fold the determination of lane capacity for 8-lane freeway; and the development of methodology determining total capacity using lane friction factor This study utilized the data collected by loop detectors at a station of FTMS in Kyungbu expressway. For determining capacities, this study analyzed maximum flow rate in various aspects such as collecting period, each lane, and total lane in one-way. In addition, this study evaluated the breakdown in traffic flow relations in order to find out interrelation of breakdown among lanes. Through this analysis, this study determined lane friction factors, critical speed, and critical density. Finally, this study expressed a new methodology of capacity analysis for multi-lane freeways using some findings from this analysis.