• International Journal of Highway Engineering
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• v.9 no.3
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• pp.91-100
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• 2007

The most important thing for driver's safety on the road is equipment of crash cushion as a vehicle protection safety facility. But development of crash cushion is defective because there's no rational and reality way of design. And also without an alternative plan, it rely on crash test hereby it suffers a great economic loss and wastes time. This study that uses data of cash test proves the suitability of single degree of freedom which considers the safety of passengers about three-dimensional complicated Crash Analysis. As the study analyzes the conduct of crash cushion, it want to develop the effective method of design on Single Degree of Freedom Crash Cushion. And it presents the way of crash cushion design through making a crash analysis model with single degree of freedom. To verify the validness of the crash cushion plan, with single degree of freedom plan, we make the level CC2 crash cushion and execute the crash test. A performance test brings satisfied result and a plan of single degree of freedom crash cushion is proven as an one of the way to be a good system which can design crash cushion.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.23-30
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• 2009

Crash cushions are protective devices that prevent errant vehicles from impacting on fixed objects. This function is accomplished by gradually decelerating a vehicle to a safe stop in a relatively short distance. Commonly used crash cushions generally employ one of two concepts to accomplish this function. The first concept involves the absorption of the kinetic energy of a moving vehicle by crushable or plastically deformable materials and the other one involves the transfer of the momentum of a moving vehicle to an expendable mass of material located in the vehicle's path. Crash cushions using the first concept are generally referred to as compression crash cushions and crash cushions using the other concept are generally referred to as inertial crash cushion. The objective of this research is the development of a compression-type crash cushion by employing the two concepts simultaneously. To minimize the number of full-scale crash tests for the development of the crash cushion, preliminary design guide considering inertial and frictional energy absorption was constructed and computer simulation was performed. LS-DYNA program, which is most widely used to analyze roadside safety features, was used for the computer simulation. The developed crash cushion satisfied the safety evaluation criteria for various impact conditions of CC2 performance level in the Korean design guide.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2D
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• pp.163-170
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• 2008

According to the rules, a crash cushion is supposed to set up products that is satisfied with the standard of a performance test after performing the car crash test by road safety facilities and management guide. For development of crash cushion, performance should be estimated through the car crash test eventually. However, there is no reasonable design method which considers passenger's safety and only depend on crash test without an alternative plan. Therefore it incurs a loss materially and takes a lot. Therefore, we are asked to create a systematic design of the crash cushion. This study shows that a scientific basis of applying single degree of freedom when it designs the crash cushion after analyzing vehicle crash test data of crash cushion and also represents design of crash cushion through single degree of freedom response spectrum using calculated by crash test data on crash cushion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.399-407
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• 2022

Energy absorption facilities installed on roads should follow the performance standards of the real-car crash test of 'Installation and Maintenance Guidelines for Roadside Safety Facilities'. However, due to different installation conditions, such as differing structure widths on roads, some energy absorption facilities do not provide adequate performance. In order to apply varied environments on roads, an energy absorption structure was designed in this study with 150 mm height and four layers of W-shape guardrail at 200 mm intervals, and the performance was verified using LS-DYNA computer simulation. Through a real-car crash test, the performance of the facility designed by LS-DYNA was tested and was found to meet the performance of the CC2 category for crash cushions. The conclusion of the comparison demonstrates that the simulation and the real-car crash tests are both significant.

• Journal of Korean Society of Transportation
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• v.20 no.7
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• pp.107-116
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• 2002

Crash Cushion is a kind of safety facilities on roadside which acts the role of absorbing impact energy when vehicles are driven out of normal route such as Gore area of freeway off ramp. Criteria for severity index considering accident occurrence possibility are needed to have strong effect on installing the facilities. However, present criteria for establishing crash cushion design do not include such processes. Therefore, the paper presents two kinds of study to develop criteria for severity index. First of all, development of accident forecasting model on freeway off ramp is presented. The module is a relationship between accidents and road environment by negative binomial distribution (NB) which is called to reflect very well quality of accidents at Gore of crash cushion installed freeway Secondly, freeway exiting behavior model is developed because the human factor is the most important one. However, many literatures have shown between road environment and accidents which are more quantitative than human factor. The study supposed advanced process steps on actual freeway and analysed correlation between variables and accidents. The criteria for severity index is presented to determine whether to install or not by benefit cost analysis for each module. The standard for severity index will help to determine whether to install the crash cushion or not and to estimate severity for freeway and off ramp.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.75-83
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• 2009

Collision behavior of clash cushion occurs for a second of less than 0.4sec usually so that it is too hard to calculate numerically. Therefore, for development of trash cushion, it rely on full-scale vehicle crash test without any design procedure. Occupant safety indices if calculated from acquired data by data measurement system and collision behavior of vehicle and crash cushion is filming using high-speed camera in the crash test. But practical ufo scope of high-speed camera is limited and it is not using to calculated the occupant safety indices or analyzed the energy dissipated mechanism of crash cushion. This work is to estimate to be suitable or not for compare the data from measurement system with the data from high-speed camera. And also it is to grope for practical use scheme to calculation of occupant safety indices or analysis of collision behavior.

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.119.2-119.2
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• 2009

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.49-57
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• 2008

The performance of crash cushion systems is certified through the full scale crash tests by the standard for installation and maintenance guidelines for roadside safety appurtenance. The impact severities of impacting vehicles in collision with crash cushion systems are rated by indices THIV and PHD. Crash test results are considered to study the performance of three crash cushion systems. In case of the frontal impact or the offset frontal impact, the results show that THIV values of three systems are very close to the threshold limit for the occupant protection. Also, the results show that PHD would be improper for the occupant protection performance index. In order to improve the occupant protection performance of crash cushions, ASI needs to be included in the impact severity index.

• Transportation Technology and Policy
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• v.8 no.4
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• pp.35-44
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• 2011

• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.261-264
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• 2010