• International Journal of Highway Engineering
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• v.18 no.3
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• pp.95-107
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• 2016

PURPOSES : This study compared two measures of traffic flow effectiveness on roads with roundabouts and signalized intersections and determined the more appropriate measure. METHODS : In addition to average delay time, the conventionally used measure, average travel time was introduced to measure traffic flow effectiveness because it is able to be obtained through field survey and reflect different travel distances and speed limits of roundabouts and signalized intersections. Using the two measures, roundabouts and signalized intersections were compared through simulations in terms of traffic flow effectiveness. RESULTS : For one-way single-lane roads, the two measures indicated consistent results that roundabouts were more effective than were signalized intersections when the traffic volume was less than 300 vphpl but vice versa when it exceeded 450 vphpl; however, the measures yielded inconsistent results when the volume was 350~400 vphpl. For one-way double-lane roads, the two measures indicated consistent results that roundabouts were more effective than were signalized intersections when the volume was less than 200 vphpl but vice versa when it exceeded 400 vphpl; however, the measures yielded inconsistent results when the volume was 250~350 vphpl. The results obtained using the two measures differed substantially for double-lane roads because behaviors such as weaving and lane changing at roundabouts are more common in double-lane roads than in single-lane roads. CONCLUSIONS : The average delay time would be lower on roads with roundabouts, but average travel time would be lower on roads with signalized intersections. Thus, evaluating the relative effectiveness of roads with roundabouts and signalized intersections by using average delay time alone would be inappropriate, whereas using average travel time as the evaluation index would yield fairer results.

• Journal of the Society of Disaster Information
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• v.7 no.1
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• pp.1-11
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• 2011

Plans of underground roads have been established, and the possibilities of underground road constructions have been growing in Korea. However, the study on characteristics of underground roads, the enactment of law, and the establishment of design criteria haven't been conducted so far, if any. Based on these backgrounds, the paper presents the basic direction on the construction method of underground roads. It also investigates the needs and characteristics of underground roads and reviews domestic and foreign examples. Major results by implementing the research are as follows: 1) when selecting the route of underground roads, the use of underground space, technical aspects, and traffic systems should be comprehensively considered; 2) the design speed of underground roads will be 10km/h above the speed limit to secure safety; 3) disaster prevention facilities should be planned to connect high traffic management system for coping with unexpected situations. Although this study has a limitation that hasn't reflected the driver's characteristics on new spaces such as underground roads, it has some significance that it suggests the major reviewing issues on the construction of underground roads, and presents the direction through the previous study.

• Journal of Korean Society of Rural Planning
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• v.16 no.3
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• pp.159-171
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• 2010

Since rapid industrialization of Korean society, out-of-village roads have been greatly improved, while almost all of in-village roads have not been fundamentally improved yet. Unless village roads should be improved in relatively comparison with trunk roads, it has been widely recognized that grass rooted achievement of accessibility revolution not be realized. In this regard, this study tried to develop evaluation indicators system for improvement of village roads. The evaluation indicator system on village road conditions was proposed which is sub-categorized as structural improvement of road itself, its communication serviceability and public securing level of property rights of road site. The system has 6 indicators(2 of each subcategory);good pavement ratio and over 3m wide road length ratio, ratio of household fronting under 2m wide road and connectivity of road network, ratio of registered as 'road' in land category and ratio of publicly owned road sites. In the final conclusion, village roads in rural Korea have been generally in worse condition regardless of whether prior improvement works or not, except some of recent plan-based improvement villages.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.6
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• pp.78-86
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• 2019

The study analyzed the greenness index that residents experience on the streets of rural areas, where characteristics are different from those of urban areas and the effects of these characteristics were investigated. In Yesan-gun, Chungnam, in order to analyze the greenness indices, the streets were categorized into 7 types. Then, two types of streetscape greenness indices were surveyed, analyzed, and compared. One is the street-trees greenness index which takes into account only the trees lining the street and the other is the street greenness index considering total artificial green, natural green, and productive green surfaces. As a result, using the street-tree greenness index the street greenness index of Yesan-gun was analyzed as 15.93% on national highways, 26.14% for local roads, 28.28% for gun-roads, 24.72% for myun-roads, 40.70% for li-roads, 32.78% for nong-roads, and 18.36% for urban planning roads. Using the street greenness index, the street-trees greenness index was analyzed to be 5.02% for national highways, 9.10% for local roads, 8.55% for gun-roads, 4.51% for myun-roads, 6.92% for li-roads, 2.56% for nong-roads, and 9.39% for urban planning roads. To analyze what factors have an impact on the street-trees greenness index and the street greenness index, the study analyzed the effects of street side-land uses, lane types, street-trees, and sidewalks. As a result, both the street greenness index and the street-trees greenness index responded according to the land use adjacent to the street, lane types, and sidewalks. The street greenness index did not change due to the existence of street-trees, but the street-trees greenness index did. Through comparison with other studies, it was found that Yesan-gun needs to improve its streetscape to improve its greenness index rating.

• Journal of Korean Society of Forest Science
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• v.103 no.3
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• pp.408-421
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• 2014

This study was carried out to investigate flora and vegetation in cutting slope along a construction age sequence (2007, 2009, 2010, 2011, 2012) of forest roads in Yongchiri, Younghyunmyon, Sacheonshi, Geyongsangnamdo. Mean slopes of the cutting and banking slopes of forest roads constructed were ranged from $42^{\circ}$ to $54^{\circ}$. Soil texture in the cutting and banking sides of forest roads constructed in 2012 was loam, while sandy loam in the cutting and banking slopes of forest roads constructed between 2007 and 2011. Vegetation cover percentage was higher in the banking slopes (66%) than the cutting slopes (49%) of forest roads. Total flora were higher in the banking slopes (50 species) than the cutting slopes (46 species) of forest roads. Species diversity was generally higher in the banking slopes than in the cutting slopes in all forest roads. In addition, the species diversity index was the highest in the cutting slopes (1.4015) of forest roads constructed in 2011, while the highest in the banking slopes (1.5603) of forest roads constructed in 2012. The results indicate that evenness index in the cutting and banking slopes of recent construction roads was high compared with old construction roads because of the distribution of simple plant species.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.79-87
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• 2015

PURPOSES: According to accident statistics for road built in 2004, the ratio of accidents on frozen roads to normal roads is 0.9%, whereas the fatality ratio is 2.7%. The risk of accidents on frozen roads is very high. Measures taken every year to prevent traffic accidents of frozen roads in the winter season are still insufficient. Additionally, measures have been established mainly on rural roads. Therefore, for urban roads, analyses and measures to prevent accidents are lacking. In this study, data on accidents on frozen roads was used to search for the causes behind these accidents and measures to reduce accidents have been recommended. METHODS: In this study, collected data from the TAMS (Traffic Accident Management System), which were collected by the Seoul National Police Agency was used. The data were divided into vehicle, people, and condition of road. The analytical model used here was the Logistic Regression Model, which is frequently used for traffic safety and accident analysis. This study uses the odds ratio analysis to search for variables related to frozen road traffic accidents in each category. A total of 18 out of 47 variables were found to be the causes of accidents. RESULTS: From the results of the comparative analysis of 18 variables, the category of the condition of the road was found to be the most critical. Contrary to expectations, more accidents occurred in clear weather than in other conditions. Accidents on bridges occurred frequently, and its odds ratio was the highest compared with other road types. When BPT is operated, the probability of accidents on frozen roads is lower than in general conditions, and accidents occurred frequently on roads with less than four lanes. CONCLUSIONS : Based on the results of this study, suggestions for reducing the risk of future domestic road accidents in freezing conditions are indicated as follows. First, it is necessary to perform a technical review of the urban road traffic accidents caused by frozen roads. Second, it is necessary to establish criteria for the study of the road environment based on the major causes of road accidents on frozen roads. Third, improvements in urban road environmental factors should be made.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.1
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• pp.123-140
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• 2022

Even though driving behaviors in underground roads can be significantly different from ground roads, existing underground roads follow the design guidelines of ground roads. In this context, this study investigates the driving behaviors of the exit-ramp terminal of urban underground roads using a driving simulator. Virtual driving experiments were performed by analyzing scenarios between the underground and ground road environments. The experiments' driving behavior data for each geometry section are compared and validated through a statistical significance test. This test showed that the speed in the underground road environment is relatively low, and the LPM tends to move away from the adjacent tunnel wall. Based on these findings, this study suggests implications and feasible solutions for improving driver's safety in the exit-ramp terminal of the underground roads.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.245-245
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• 2005

This paper addresses the use of directional textural information for connecting road segments. In urban scene, some roads are occluded by buildings, casting shadow of buildings, trees, and cars on streets. Automatic extraction of road network from remotely sensed high resolution imagery is generally hindered by them. The results of automatic road network extraction will be incomplete. To overcome this problem, several perceptual grouping algorithms are often used based on similarity, proximity, continuation, and symmetry. Roads have directions and are connected to adjacent roads with certain angles. The directional information is used to guide road fragments connection based on roads directional inertia or characteristics of road junctions. In the primitive stage, roads are extracted with textural and direction information automatically with certain length of linearity. The primitive road fragments are connected based on the directional information to improve the road network. Experimental results show some contribution of this approach for completing road network, specifically in urban area.

• Journal of the Korean Society of Safety
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• v.23 no.2
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• pp.65-71
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• 2008

As the interest in traffic safety has been increasing recently, social movement is being made to reduce the number of traffic accidents and the view on improving the mobility of the existing roads is being converted into on establishing traffic safety as a priority. The increase of traffic accidents related to an intersection in a state that traffic accidents are decreasing overall may suggests the necessity to investigate the specific causes. In addition, we have to consider them when establishing the measures against traffic accidents in a intersection by investigating and analyzing the influences and factors that may affect traffic accidents. To induce the accident severity model, we collected the factors that affect accidents and then applied the Poisson Regression Model among nonlinear regression analysis by verifying the distribution of variables. As a result of the analysis, it turned out that the volume of traffic on main roads, the right turn ratio on sub-roads, the number of ways out on sub-roads, the number of exclusive roads for a left turn, the signals for a right turn on main roads, and an intersect angle were the factors that affect the accident severity.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.88-94
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• 2004

Recently, vehicle simulators are widely used to evaluate driver's responses and driver assistance systems. It needs much effort to construct the virtual driving environment for a vehicle simulator. In this study, it is described how to make effectively the roads and the driving environment for a vehicle simulator. The GIS (Geographic Information System) is used to construct the roads and the environment effectively. Because the GIS is the integrated system of geographical data, it contains useful data to make virtual driving environment. First, the outline and centerline of roads is abstracted from the GIS. From the road outline, the road width is calculated. Using the centerline, the grid model of roads is constructed. The final graphic model of roads is constructed by mapping road image to the grid model according to the number of lanes and the kind of surface. Data of buildings from the GIS are abstracted. Each shape and height of buildings is determined according to kind of buildings, the final graphic model of buildings is constructed. Then, the graphic model of roadside tree is also constructed. Finally, the driving environment for driving simulator is constructed by converting the three graphic models with the graphic format of Direct-X and by joining the three graphic models.