• Journal of Korean Society of Transportation
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• v.35 no.2
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• pp.129-142
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• 2017

Accident Black Spot Improvement Project is the representative road safety intervention to eliminate environmental risk factors on the roadway by installing road safety facilities. Although it is one of the main road safety projects in Korea, there has been a lack of effort analyzing the traffic accident reduction effects of this project. In this study, therefore, we selected 4,171 road black spots from 2004 to 2013 and investigated the traffic accident reduction effects of 5 road safety facilities by using "Comparison Group(C-G)" method. Through the analysis, it was found that the number of traffic accidents were lowered by 4.45% with traffic islands, 32.17% with road paved markers, and 24.13% with speed cameras, respectively. However, 0.61% with pedestrian fencing and 1.67% with skid resistant pavement were increased on the other hand. In addition, we also analyzed traffic accident reduction facilities' performance on specific types of collision mentioned in manual on road safety facilities by Ministry of Land, Infrastructure and Transport. It was shown that the number of bad weather traffic accidents were reduced by 52.96% with road paved markers, pedestrians accidents were reduced by 62.77% with pedestrian fencing and rear-end collisions were reduced by 26.00% with skid resistant pavement.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.27-34
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• 2009

The operational effect of traffic signal control improvement was evaluated using the Two-Fluid Model. The parameters engaged in the Two-Fluid Model becomes food indicators to measure the quality of traffic flow due to the improvement of traffic signal operation. A series of experiment were conduced for the 31 signalized intersections in Uijeongbu City. To estimate the parameters in the Two-Fluid Model the trajectory informations of individual vehicles were collected using the CORSIM and Run Time Extension. The test results showed 35 percent decrease of average minimum trip time per unit distance. One of the parameters in the Two-Fluid Model is a measure of the resistance of the network to the degraded operation with the increased demand. The test result showed 28 percent decrease of this parameter. In spite of the simulation results of the arterial flow, it was concluded that the Two-Fluid Model is useful tool to evaluate the improvement of the traffic signal control system from the macroscopic aspect.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.3
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• pp.20-37
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• 2023

Although traffic signal installations are continuously expanding, the effect of preventing traffic accidents remains unverified. Totally, 7,045 traffic accident data (such as signal violations) registered with TCS were manually searched for a 7-year period from 2013 to 2019 for 1,602 traffic signals in Daejeon Metropolitan City. The top 20 traffic accident intersections were identified, the traffic accident investigation records and field maps were viewed to compare the driving direction and signal phase of the violated vehicle, and the cause of the traffic accident was divided into insufficient signal operation design (operation) and driver negligence (intentional). Results of the analysis revealed that 75% of traffic accidents occurred in thru-left-turn traffic signals and overlap; moreover, extending the yellow time or operating all red signals due to countermeasures against traffic accidents occurring in yellow signals resulted in reduced traffic accidents. Data indicated that Permissive Left Turn requires improvement with the signal operation. In addition, since The Korean National Police Agency is not computerized for traffic accident sites and signal-related data, the lack of manpower necessitates improvement and utilization of TCS when establishing traffic accident prevention measures. It is believed that it will contribute to signal operation by analyzing vast amounts of data collected in the field and presenting improvement measures.

• Journal of Coastal Disaster Prevention
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• v.5 no.4
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• pp.193-201
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• 2018

The recent increase in size and speed of ships resulted in the existing maritime routes becoming narrow relative to the size of new ships. At the same time, as the improvement and optimization in marine transportation take place and the construction of structures in seas and harbor improvements pick up speed, there is an increasing probability of marine accidents. Due to these environmental changes, the need to professionally analyze the effect of marine structures on navigation arose to ensure safety of ships and a law was enacted and introduced for the Maritime Traffic Safety Audit (MTSA). In this study, a Qualitative assessment for verifying the effectiveness of MTSA was carried out with case analysis and analysis model in other similar audit scheme. It is expected that an analyzed result for effectiveness of MTSA will be a steppingstone for enhancing the MTSA and keeping maritime traffic safety as its own purpose.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6D
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• pp.623-636
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• 2012

Roundabout is an intersection that allows vehicles to pass through the intersection by circulating the circular traffic island at the center of the intersection. In this study, a comparative analysis was conducted on roundabout at five locations in order to deduce the operational result and financial effect of roundabout and signal intersection. As for the operational result, it was found that roundabout showed improvement effect in the average delay per vehicle compared to that of signal intersection by minimum of 65.6% and maximum of 91.77%. it was found that roundabout showed financial cost-saving effect in the traffic congestion cost compared to that of signal operation by minimum of 58.59% and maximum of 81.69% per year. It can be known from these analysis results that roundabout has significant operational effects under certain amount of traffic volume by allowing vehicles to pass through the intersection in a continuous way without much waiting time and stoppage from signal control.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.3
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• pp.1-19
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• 2021

The domastic hard shoulder running(HSR) System has been gradually expanding since its initial implementation in September 2007 with the aim of increasing capacity and resolving congestion. Hard Shoulder is used as a space for driver's visual comfort and a place for vehicles to evacuate in case of emergency, but it is replaced by a space for driving when the HSR System is implemented. Therefore, it was intended to determine the improvement effect before and after implementation of the HSR system through safety analysis and mobility analysis. The safety analysis analyzed the impact of traffic accidents by comparing HSR sections and similar sections. The mobility analysis was to determine the improvement effect by quantifying the speed and traffic volume changes before and after HSR System implementation. According to safety yanalysis, there is no effect of reducing traffic accidents when implementing the HSR System. In mobility analysis, the implementation of the HSR System significantly improved the speed of traffic during peak hours and significantly reduces slow and delay hours.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.81-94
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• 2007

In order to solve the traffic problem which comes to be serious at day, the impotance of Intelligent Transport Systems(ITS) that accomplish information gathering, information processing, information offering with up-to-date scientific techniques is coming to be high. But many local self-government group want to solve the traffic problems with introduction of ITS, however, it is a actual condition where the systematic effective analysis is insufficient. This study establishes the methodology of effective analysis as introduction of ITS, which refers to the inside and outside of the country instance. And then, this research accomplishes direct and indirect effective analysis with the case study. As a result of SUWON ITS introduction effect analysis, the travel speed of TRC mode is increased 31%, and the delay of TRC mode is diminished 43.9% than before introducing case. Most of the citizen felt the improvement effect of ITS system operation, and the majority wanted the expansion of the ITS system in survey. The analysis of economic result that B/C ratio is 5.12. So, The the effect and economic propriety of the ITS enterprise appeared with the fact that it is sufficient.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.16-24
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• 2023

Accidents are greatly reduced through projects to improve frequent traffic accidents. These results show that safety facilities play a big role. Traffic accidents are caused by various causes and various environmental factors, and it is difficult to achieve improvement effects by installing one safety facility or facilities without standards. Therefore, this study analyzed the improvement effect of each accident type by combining the two safety facilities, and suggested a method of predicting the combination of safety facilities suitable for a specific point, including environmental factors such as road type, road type, and traffic. The prediction was carried out by selecting an XGBoost technique that creates one strong prediction model by combining prediction models that can be simple classification. Through this, safety facilities that have had positive effects through improvement projects and safety facilities to be installed at points in need of improvement were derived, and safety facilities effect analysis and prediction methods for future installation points were presented.

• ETRI Journal
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• v.28 no.1
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• pp.31-44
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• 2006

In a packet switching network, congestion is unavoidable and affects the quality of real-time traffic with such problems as delay and packet loss. Packet fair queuing (PFQ) algorithms are well-known solutions for quality-of-service (QoS) guarantee by packet scheduling. Our approach is different from previous algorithms in that it uses hardware time achieved by sampling a counter triggered by a periodic clock signal. This clock signal can be provided to all the modules of a routing system to get synchronization. In this architecture, a variant of the PFQ algorithm, called digitized delay queuing (DDQ), can be distributed on many line interface modules. We derive the delay bounds in a single processor system and in a distributed architecture. The definition of traffic contribution improves the simplicity of the mathematical models. The effect of different time between modules in a distributed architecture is the key idea for understanding the delay behavior of a routing system. The number of bins required for the DDQ algorithm is also derived to make the system configuration clear. The analytical models developed in this paper form the basis of improvement and application to a combined input and output queuing (CIOQ) router architecture for a higher speed QoS network.

• International Journal of Highway Engineering
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• v.18 no.5
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• pp.127-134
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• 2016

PURPOSES : Visibility of lanes on the road improves as retro-reflectivity rises. This helps reduce traffic accidents at nighttime or in bad weather. This study aimed to evaluate the effects of improved visibility on reduction of traffic accidents when the color of the lane in the median of the highway was changed from yellow to white. METHODS : In order to evaluate the accident reduction effect of the white left shoulder line, Hauer (1997)'s Comparison-Group method was chosen as an analysis methodology. The JungBu-2 highway, which is equipped with the white left shoulder line and is in trial operation, was chosen as a target for analysis. Data of accidents for 10 months before and after installation was collected and analyzed. In addition to the number of accidents, the types of accidents were classified into nighttime accidents, accidents in bad weather, and median collisions. The accident reduction effect of improved visibility of lanes was analyzed. RESULTS : The analysis' finding showed that installation of the white left shoulder line decreased the number of accidents by 28%. Moreover, improvement in visibility was effective in reducing nighttime accidents by 67.63%, accidents in bad weather by 55.19%, and median collisions by 48.55%. CONCLUSIONS : Based on the analysis' results in this study, it was concluded that white left shoulder line on the freeway contributed to reduce traffic accidents, especially nighttime accidents, accidents in bad weather, and median collisions.