• International Journal of Highway Engineering
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• v.15 no.2
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• pp.131-138
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• 2013

PURPOSES : The intents of the study are to identify the accident factors and to demonstrate the potentials of tobit model as a tool to study the number of accidents on arterial roads segments. METHODS : This paper uses a tobit regression as a methodology to analyze the factors affecting the number of accidents. In pursuing the above goal, this study gives particular attentions to analyzing the data of 2,446 accidents (1,610 in major arterial roads and 836 in minor arterial roads) occurred on arterial roads in 2007 to 2010. RESULTS : First, 3 accident models which were classified by total arterial roads, major arterial roads and minor arterial roads, and were all statistically significant were developed. Second, the exclusive right-turn lane as common variable, and the number of accident, traffic volume, number of lanes, link length, rate of median, number of entrances, number of pedestrian crossings, number of curves, number of bus stops and exclusive left-turn as specific variables of the models were selected. Finally, the paired sample t-test could not be rejected the null hypotheses of three types of models. CONCLUSIONS : Using data from vehicle accidents on arterial roads, the estimation results show that many factors related to roadway geometrics and traffic characteristics significantly affect to the number of accidents.

• 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.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.2
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• pp.47-56
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• 2015

At the present, the mechanized form roads pavement was constructed with plain concrete. Mostly, it was used by welded wire mesh for preventing crack. Cellulose fibers for the reinforcement of concrete offer relatively high levels of elastic modulus, fiber count (per unit weight), specific surface, and bond strength to cement-based materials. The construction of concrete pavement confirmed that cellulose fiber reinforced concrete was applicable to mechanized form roads pavement. In the study, cellulose fibers were used here at 0.08 % volume fraction, which is equivalent to a fiber content of $1.2kg/m^3$. Cellulose fiber reinforced concrete were compared with plain concrete. Field test results indicated that cellulose fiber reinforced concrete showed slightly to increase of 28 days compressive strength and improved the initial strength. it tended to increase of splitting tensile strength. Test results showed that the slump and air content tend to decreased. but, the variation of air contends is very little. Also, construction cost of cellulose fiber reinforced concrete is less than about 25.7 % the case of welded wire mesh previously used. Therefore, The cost reduction is expected to be possible in construction site by mechanized form roads pavement.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.33-43
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• 2006

This research is to the selection of optimal probability distribution as well as the estimation for design hourly factor in consideration of traffic characteristic, such as road function, lane number and AADT. To accomplish the objectives, we are applied to various probability distribution using traffic data that observed at permanent traffic count points in 2005. The parameters or the selected 14 probability distribution were estimated based on the method of maximum likelihood and the validity condition of the estimated parameter The goodness-of-fit test, such as chi-square test. was performed as well as the estimation of design hourly factor. As a result, An appropriate distributions of each case were selected : Pearson V for two lane of rural roads, LogLogistic for the four lane of rural roads, LogLogistic for the urban roads, Extreme value for recreation roads. And optimal K factor are as following : $0.1{\sim}0.2 $ for two lane of rural roads, $0.09{\sim}0.14$ for the four lane of rural roads. $0.07{\sim}0.13$ for the urban roads, $0.1{\sim}0.2$ for recreation roads.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.3
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• pp.362-368
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• 2017

The endurance test is important to evaluate and predict defects of the vehicles. In particular, in order to improve the reliability of the endurance test for the powertrain system of military vehicles, the driving load is measured and analyzed at test courses and maneuvering roads. As a result, new test courses for powertrain system is additionally needed to improve test reliability. In this paper, it shows that new test courses for powertrain system is designed and constructed using the measuring and anlayzing result between CPG test courses and army maneuvering roads.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.73-79
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• 1998

For the design and development of the wheel type excavator, the dynamic effects of travelling on the performance of the equipment should be first analyzed and conside- red in the initial design stage. In order to test the durability of the equipment in a short period, th travelling test should be performed over accelerated durability test tracks. which is more severe than general field roads such as city road, paved road, unpaved road and rough road. In this paper, a parametric study is performed in order to determine important design parameters of durability test track of a wheel type excavator. A rigid body model is developed using DADS and dynamic analysis is performed for the equipment travelling over several test roads with different severity. A comparison of test and analysis results is also presented.

• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.326-331
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• 2006

The durability of recent motors is longer than the past one because there are the rapid technique development of the automobile industry and the vehicle maintenance of users. And then the importance of the durability test due to vibration is increased from day to day. So full vehicle and parts companies accomplish the durability test using various methods. The most public test method among them is the reliable field test but it bring on higher cost and period of the development process. The durability test using MAST(multi axis simulation table) is a solution in order to improve the development process of automobiles. Generally its excitation source uses the optimized road profiles that are obtained by the road test of belgian road, country road, cobbleston road and so on instead of a real field but the interrelations and influences accordingly vehicle damage are considered by a field test between specific roads and real fields in the first place. Therefore this study, in order to accomplish a basic research for the durability test using the MAST, performed on the real field driving test at various domestic roads and the results which are analyzed by PSD(power spectrum density) are compared with relative sensitivity among the roads. Consequently they can present a basic material for generation of road profiles which is applied to the durability test using MAST.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.234-243
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• 2018

Since September 2017, a small diesel vehicle certification test mode has been enhanced from NEDC to WLTC. The main reason for the change of the certification test mode is that the certification test mode of the emission control standard of the diesel vehicle does not sufficiently reflect various driving patterns of the actual roads. Several automakers have developed after-treatment systems such as LNT, SCR, and DPF to meet enhanced emissions regulations. In this study, four small diesel cars were selected for sale in Korea, and the exhaust gas measurement test was performed in the WLTC mode, which reflects the driving characteristics of the actual roads. As a result of test, LNT vehicle exceeded Euro 6 NOx regulation and SCR vehicle satisfied Euro 6 NOx regulation. In addition, both LNT and SCR systems showed high NOX emission characteristics due to speed, RPA and Vxa. For the PN, all test vehicles were fitted with a DPF and met the Euro 6 PN regulations, with similar PN emissions results in LNT and SCR system.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.204-208
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• 2006

This study is to develop a distributed urban flood runoff model that simulates the road runoff and to test the applicability of the model by applying to Pyeongtaek city of $12.2km^2$. To generate the runoff along the runoff, agree burned DEM (Digital Elevation Model) with road networks was suggested and the proper spatial resolution of DEM was identified finer than 15 m. To test the model applicability, 32 points on the road networks were selected and the hydrographs of each point were generated. The test showed reasonable results that increase the road runoff from the high elevation roads to the low elevation roads and the road runoff considering rainwater drainage from the road also showed reasonable results.