• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.845-853
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• 2017

The main reason for urban traffic problems is the increasing in the use of private cars. In order to solve this problem, strong traffic demand management policies such as the collection of congestion tolls and the crackdown on freight vehicles are emerging. Now, however, it is necessary to seek ways for users to make changes in traffic behavior through direct communication between public agencies and passenger car users. As a technique to make this possible, mobility management, which aims to use rational passenger cars by inducing behavior change through individual consciousness change, has recently been proved to be effective in overseas. Therefore, this study concluded that the introduction of MM, which emphasizes individual voluntary behavior change, is necessary at present. In order to investigate the ways of inducing voluntary changes in traffic behavior of passenger car users, a questionnaire survey was conducted on traffic experts and the priorities of voluntary traffic behavior change measures were calculated using AHP. As a result of the analysis, it was shown that "to actively appeal to change the traffic behavior by using the mass media" was the top priority. The next priority were in order of company education for the change of traffic behavior, education for the school, and small-scale workshops.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.3
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• pp.73-82
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• 2017

As of December 2016, the number of registered automobiles in Korea exceeds 21million. As a result, greenhouse gas emission by transportation sector are increasing every year. It was concluded that the development of the driving strategy considering the driving behavior and the road conditions, which are known to affect the fuel efficiency and the greenhouse gas emissions, could be the most effective fuel economy improvement. Therefore, this study aims to develop a fuel efficient driving strategy in a complex linear section with uphill and curved sections. The road topography was designed according to 'Rules about the Road Structure & Facilities Standards'. Various scenarios were selected. After generating the speed profile, it was applied to the Comprehensive Modal Emission Model and fuel consumption was calculated. The scenarios with the lowest fuel consumption were selected. After that, the fuel consumption of the manual driver's driving record and the selected optimal driving strategy were compared and analyzed for verification. As a result of the analysis, the developed optimal driving strategy reduces fuel consumption by 21.2% on average compared to driving by manual drivers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.111-117
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• 2017

The purpose of forecasting the traffic accident is to reduce the traffic accident. Therefore, the goal of this study is to provide severity of the accident by Forecasting of Probability of Accident. In Korea, accident data are distributed to the public via internet that includes numbers of accident and fatality as well. And crude level of accident severity in accordance with weather information for metropolitan city level are available by weekly. However, It can not reflect personal needs at specific origin of the travel for a certain traveller. This study aims to consider 68 major intersections with precipitation data, and eventually introduces link based accident severity. In estimating the accident severity both dynamic data such as drivers' characteristics, driving conditions and static data such as geometry of road, intersection characteristics are considered. Also, we identifies accident severity according to the accident type - 'vehicle to vehicle,' 'vehicle to person.' Finally, the outcomes of this study suggests taylor-made accident severity information for a specific traveller for a certain route.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.28-34
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• 2014

Automatic transmission fluid (ATF) is used for automatic transmissions in the vehicle as the characterized fluid. Recently, the vehicle manufacture usually guarantee for fluid change over 80000~100000 km mileage or no exchange, but most drivers usually change ATF below every 50000 km driving in Republic of Korea. It can cause to raise environmental contamination by used ATF and increase the cost of driving by frequently ATF change. In this study, we investigate the various physical properties such as flash point, fire point, pour point, kinematic viscosity, cold cranking simulator, total acid number, and metal component concentration for fresh and used ATF after driving (50000 km, 100000 km). The result showed that the total acid number, pour point, Fe, Al and Cu component had increased than fresh ATF, but 2 kind of used oil (50000 km and 100000km) had similar physical values and metal component concentration.

• Journal of Korean Society of Transportation
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• v.31 no.1
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• pp.3-13
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• 2013

This paper reviews the characteristics of dilemma zone by analysing the influence exerted by actual location of intersection traffic signal on behaviour of drivers approaching signalized intersection in urban area. The analysis of approach speed was based upon a 'before and after' comparison, measured at three sites where the locations of traffic signals were changed. The study demonstrated that, when traffic signal changed to yellow, the scales of dilemma zone were narrowed in case of stopping cars by moving up the starting point of the dilemma zone due to lowered spot speed. On the other hand, in case of passing cars, the end points of dilemma zone were moved further out to the rear due to increased spot speed. Therefore, changing traffic signal locations could make an impact to increase intersection safety through reducing the scales of dilemma zone. This study also found that, in cases involving vehicles with similar approach speeds, spot speeds could be differentiated following the change of signal locations due to the fact that there can be greater differences in both braking point and deceleration rate. Thus, when considering the appropriate measuring of dilemma zone, 'spot speed' rather than 'approach speed' appeared to be more appropriate criterion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.5
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• pp.595-603
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• 2019

To alleviate the demand on private car that is constantly increasing, Busan Metropolitan City (BMC) has established Bus Rapid Transit (BRT) to revitalize public transportation. But there are no unified lane system between BRT and general bus stations, which makes off-lane turning general bus to contribute to congestion. And as the bottleneck phenomenon at entrance/exit accelerates the congestion, there has been huge dissatisfaction among commuting drivers. Therefore, this study identifies efficient methods to operate better through measuring civilian awareness. We evaluate both satisfaction and drawbacks on BRT service with Importance-Performance Analysis (IPA). We first distinguish the groups by the awareness on BRT and their main transit usage, and then clarify the difference between the groups. And as a result, the group who is positive to BRT and uses buses often demands improvement in bus indoor comfort and curbing jaywalking. On the other hand, group who is negative to BRT and uses private cars often demands improvement in lane changing and the moving speed of private cars. We next examines the groups with MDPREF, one method of Multidimensional Scaling (MDS). And we have clarified that the evaluating criteria and the individual attributes of the groups corresponds very well.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.493-499
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• 2023

Recently, with the development of construction machinery, low-vibration construction machine such as Tricone-Bits, which can drill both soil and rock layers and minimize vibration, is being used frequently. However, although many studies have been conducted on the prediction of vibration values for earth augers and pile drivers, the reality is that studies on the effects of vibration on low-vibration drilling equipment are lacking. In this paper, ground vibration values for Tricone-Bits were measured, and a vibration distance damping formula was proposed using this. In addition, after predicting the vibration of the earth auger and pile driver using the previously proposed vibration distance damping formula, the degree of vibration damping for the Tricone-Bits was evaluated by comparing and analyzing it. As a result, the Tricone-Bits showed a vibration reduction effect of 97% and 93% compared to these machine and It will help with management and prediction of the ground vibration effects evaluation on the low-vibration equipment such as Tricone-Bits.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2B
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• pp.169-177
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• 2010

Recently due to the typhoon and extreme rainfall induced by abnormal weather and climate change, the probability of severe damage to human life and property is rapidly increasing. Thus it is necessary to create adequate and reliable flood risk map in preparation for those natural disasters. The study area is Seo-gu in Daegu which is located near Geumho river, one of the tributaries of Nakdong river. Inundation depth and velocity at each time were calculated by applying FLUMEN model to the target area of interest, Seo-gu in Daegu. And the research of creating flood risk map was conducted according to the Downstream Hazard Classification Guidelines of USBR. The 2-dimensional inundation analysis for channels and protected lowland with FLUMEN model was carried out with the basic assumption that there's no levee failure against 100 year precipatation and inflow comes only through the overflowing to the protected lowland. The occurrence of overflowing was identified at the levee of Bisan-dong located in Geumho watershed. The level of risk was displayed for house/building residents, drivers and pedestrians using information about depth and velocity of each node computed from the inundation analysis. Once inundation depth map and flood risk map for each region is created with this research method, emergency action guidelines for residents can be systemized and it would be very useful in establishing specified emergency evacuation plans in case of levee failure and overflowing resulting from a flood.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1D
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• pp.1-10
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• 2010

Safety improvement has been a continuous challenge, especially at toll gate of express highway where traffic conflict often occurs due to frequent lane change by drivers of "Hi-pass" lane and regular "TCS" lane. As a part of research on safety at toll gate, this study videotaped traffic conflict data between vehicles using centrally located "Hi-pass" lane and regular "TCS" lane and analyzed accident risk. According to the correlation analysis of vehicle speed, relative vehicle speed, and sudden vehicle deceleration rate due to traffic conflict, when the relative vehicle speed between centrally located "Hi-pass" lane and regular "TCS" lane increases, sudden vehicle deceleration rate also increases. One of the findings is that centrally located "Hi-pass" lane at toll gate shows different location for traffic conflict, and frequency of traffic conflict and the relative vehicle speed was also different based on vehicle lane use. TA (Time to Accident) analysis shows that accident rate is high at toll gate where Hipass lane is installed in center lane, when the occurrence of sudden vehicle deceleration and deceleration time of vehicles rise for vehicles on "Hi-pass" lane. Furthermore, if the expressway entrance/exit point is closely located to toll gate, TA showed a low value. Thus, it is necessary to reduce the relative vehicle speed in order to improve safety. The Study presents reduction of the relevant vehicular speed and prevention of accidents at the centrally installed "Hi-pass" lane as an important strategy for safety improvement at toll gate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.63-73
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• 2024

Autonomous vehicles at Levels 3 to 5, currently under global research and development, seek to replace the driver's perception, judgment, and control processes with various sensors integrated into the vehicle. This integration enables artificial intelligence to autonomously perform the majority of driving tasks. However, autonomous vehicles currently obtain temporary driving permits, allowing them to operate on roads if they meet minimum criteria for autonomous judgment abilities set by individual countries. When autonomous vehicles become more widespread in the future, it is anticipated that buyers may not have high confidence in the ability of these vehicles to avoid hazardous situations due to the limitations of temporary driving permits. In this study, we propose a method for grading the judgment abilities of autonomous vehicles based on a driving simulator experiment comparing and evaluating drivers' abilities to avoid hazardous situations. The goal is to derive evaluation criteria that allow for grading based on specific scenarios and to propose a framework for grading autonomous vehicles. Thirty adults (25 males and 5 females) participated in the driving simulator experiment. The analysis of the experimental results involved K-means cluster analysis and independent sample t-tests, confirming the possibility of classifying the judgment abilities of autonomous vehicles and the statistical significance of such classifications. Enhancing confidence in the risk-avoidance capabilities of autonomous vehicles in future hazardous situations could be a significant contribution of this research.