• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.111-116
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• 2012

This study deals with the traffic accidents of circular intersections in Korea. The purposes are to comparatively analyze the characteristics by operational type, and to develop the models using the data of 82 intersections. In pursuing the above, this study gives particular emphasis to modeling such the accidents as the roundabout and rotary in urban area. The main results analyzed are as follows. First, the null hypotheses that the number of accidents are the same in both the urban and rural intersections, and roundabout and rotary in urban area, were analyzed to be rejected. Second, 3 accident models were developed, which were all statistically significant. The independent variables used in the above models are the ADT, number of approach lane, bus stop, parking facilities, and others. This study could be expected to give some implications to the traffic safety policy decision-making.

• Journal of Korean Society of Transportation
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• v.34 no.5
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• pp.449-464
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• 2016

The purpose of this study is to test applicability of cut-through roundabouts at a congested intersection and to provide the traffic volume ranges for theirs application. Various test scenarios were developed according to variation of total traffic volume, left-turn ratio to total traffic volume, and ratio of major road traffic volume to minor road traffic volume. In addition, three intersection types of cut-through roundabout, roundabout, and signalized intersection were compared with respect to delay times for each scenario, resulted from the simulation using VISSIM. In case of the ratio of major road traffic volume to minor road traffic volume, 6:4, the delay times of cut-through roundabout decreased up to 30% of left-turn ratio to total traffic volume for 400vphpl, up to 20% for 500vphpl, up to 10% for 600vphpl. In case of the ratio, 7:3, they are the same as 6:4 for 400vphpl, 500vphpl, and 600vphpl but they decreased up to 30% for 300vphpl and up to 10% for 700vphpl. In case of the ratio, 8:2, they are the same as 7:3 for 400vphpl, 500vphpl, and 700vphpl but they were reduced by 10% to 30% for 300vphpl and 20% for 600vphpl. It is concluded that the smaller left-turn ratio to total traffic volume as well as the ratio of minor road traffic volume to major road traffic volume is, the more effective in reducing delay times the cut-through roundabout is. Cut-through roundabouts can be expected to reduce delay times at a signalized intersections with traffic conditions above-mentioned.

• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.110-116
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• 2016

The rapid expansion of buildings and paved roads increases the risk of flood disaster in an urban area. One of the solutions can be the use of permeable pavements. This study evaluated the permeability of permeable blocks used for the roadway pavement. Joint fillers and mat sands of the investigated blocks met the corresponding standards. The flexural strength of the blocks was 5.29 MPa to meet these standards. Based on interior permeability test results after pollution, the four products evaluated were categorized into the following three levels: One for the $1^{st}$ level, one for the $2^{nd}$ level and two for the $3^{rd}$ level. From the field permeability test and pervious concrete infiltration test results nine months after their construction, all the products except one passed the quality standards of 0.1 mm/s.

• Journal of Auto-vehicle Safety Association
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• v.14 no.3
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• pp.65-70
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• 2022

Lane change in urban environments is a challenge for both human-driving and automated driving due to their complexity and non-linearity. With the recent development of deep-learning, the use of the RNN network, which uses time series data, has become the mainstream in this field. Many researches using RNN show high accuracy in highway environments, but still do not for urban environments where the surrounding situation is complex and rapidly changing. Therefore, this paper proposes a lane change possibility decision network by adopting Attention layer, which is an SOTA in the field of seq2seq. By weighting each time step within a given time horizon, the context of the road situation is more human-like. A total 7D vectors of x, y distances and longitudinal relative speed of side front and rear vehicles, and longitudinal speed of ego vehicle were used as input. A total 5,614 expert data of 4,098 yield cases and 1,516 non-yield cases were used for training, and the performance of this network was tested through 1,817 data. Our network achieves 99.641% of test accuracy, which is about 4% higher than a network using only LSTM in an urban environment. Furthermore, it shows robust behavior to false-positive or true-negative objects.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.535-542
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• 2010

Various difficulties have been increased in the construction of public structure; like the road in the overcrowding urban area, because of civil complaint, cost and period of construction. In oder to overcome these social problems, the tunnel has been planned the road design. Despite the resolution, there are many technical problems when constructed near facilities. The design of new tunnel below the existing service reservoir is applied to the ambient vibration blasting using Plasma. The result of test blasting was exceeded the standard ("2kine"). So it was considered a countermeasure for the vibration reduction applied to change the controlled blasting method, reduce the charge, add the pre middle horizontal hole in the cut blasting site, and so on. The result was satisfied the standard. Accordingly, if the quality of blasting process can be managed well, the application of this alternative method is highly effective one. Also, based on cost analysis between two methods, the alternative method is very competitive.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.63-73
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• 2011

Travel speed is an important parameter for measuring road traffic. UTIS(Urban Traffic Information System) was developed as a mobile detector for measuring link travel speeds in South Korea. After investigation, we founded that UTIS includes some missing data caused by the lack of probe vehicles on road segments, system failures and etc. Imputation is the practice of filling in missing data with estimated values. In this paper, we suggests a new model for imputing missing data to provide accurate link travel speeds to the public. In the field test, new model showed the travel speed measuring accuracy of 93.6%. Therefore, it can be concluded that the proposed model significantly improves travel speed measuring accuracy.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.67-75
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• 2011

Domestic economic development, industrialization, and urbanization have brought along not only increased highway traffic but also elevated traffic noise levels. Thus, it is necessary to accurately predict the traffic noise levels in order to address the public demand of alleviating the noise levels in urban areas. In this study, the method of evaluating the sound power level of road traffic was investigated in terms of considering the types of road surface and vehicle, based on previous researches. Regarding CPX (Close Proximity Test) and Pass-by test, the measured noise data of Test Road of Korea Highway Corporation were utilized in order to construct the database of sound power levels of various vehicles. Specifically, the 38 noise measurement and analysis in 1/1-octave band frequencies at 12 pre-selected sites were carried out, considering topography and road surface. Finally, the comparison study was conducted between predicted and measured data in terms of traffic noise. The traffic noise prediction was based on the KRON (Korea Road Noise) program, which was developed being equipped wit 3-dimensional GUI. In addition, the traffic noise characteristics were evaluated in terms of vehicle types and pavement surface conditions.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.32-49
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• 2024

In this paper, we analyzed the impacts of road traffic conditions and speed limit changes on traffic flow and safety. Travel speed and moving speed were set as traffic flow indicators and'moving speed-travel speed',speed deviation, large speed deviation ratio, and number of conflicts were set as safety indicators, and the impacts of changes in road traffic conditions and speed limits on these were analyzed. According to the analysis results, the speed limit had a significant impacts on the traffic indicators, but did not significantly affect the safety indicators. As a result of the statistical validity test, it was proven that the traffic flow index increases as the speed limit increases. However, although safety indicators often increase, their validity has not been proven statistically. Therefore, if the speed limit is set and operated by properly considering the traffic flow status according to various road conditions and changes in traffic volume, it can be said to match the speed at which drivers drive and improve traffic flow and safety. Therefore, it is expected that calculating the speed limit considering the traffic flow indicators and safety indicators presented in this paper and operating the speed limit according to changes in traffic volume will contribute to stabilizing the traffic flow on the road.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.455-463
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• 2011

Conventional construction technologies have been continually applied without consideration of its impact to the environment. This resulted to various problems including the negative responses of local citizens that regarded some constructed facilities as aversive facilities causing environmental and hydraulic problems in the urban area, etc. To prevent these problems, therefore, alternative methods should be undertaken. A new approach termed "Low Impact Development (LID)" technology is currently adapted in developed countries around the world. This study aims to investigate the efficiency of the developed small constructed wetland (SCW) with horizontal subsurface flow as a LID technique applicable in urban areas. Two test-bed facilities were constructed and monitoring had been conducted between July 2010 and June 2011. Based on the findings, the removal efficiencies achieved for TSS, $COD_{Cr}$, TN, TP, Total Fe, Total Pb for the SCW-1 were 66, 53, 46, 55, 67 and 50%, respectively. On the other hand, the SCW-2 attained 82, 62, 51, 48, 74 and 42% efficiency for TSS, $COD_{Cr}$, TN, TP, Total Fe, Total Pb, respectively. The results indicated that the removal of particulate matter and heavy metals which are considered as main pollutants from stormwater runoff in urban areas was satisfactory in the system. Therefore, the test-beds proved to be appropriate for the treatment of pollutants in urban landuses such as road, parking lot, etc. The results of this study can contribute to the conservation of aquatic ecosystems and restoration of natural water cycle in the urban areas.

• Journal of Environmental Science International
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• v.13 no.8
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• pp.733-737
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• 2004

FThe aim of this study was to carry out a preliminary test of the air quality modelling system (HIRES-AIRCHEM) developed at The University of New South Wales, particularly with regard to the forecast ozone distribution. This was achieved by assimilating the New South Wales State Environment Protection Authority (EPA) emissions inventory, consisting of road and non-road sources, and running the system over the Sydney metropolitan area for the four day period 25-28 February 1998. During this period ozone readings exceeded the EPA's goal of 8pphm on several occasions. The model forecasts of ozone distribution verified well with the EPA's ozone readings. This result has important implications for possible future use of the system as a tool for routinely predicting and assessing air quality.