• Journal of Korean Society of Transportation
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• v.29 no.3
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• pp.73-82
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• 2011

Recent advancement in traffic surveillance systems has allowed the researchers to obtain more detailed vehicular movement such as individual vehicle trajectory data. Understanding the characteristics of interactions between leading and following vehicles in the traffic flow stream is a backbone for designing and evaluating more sophisticated traffic and vehicle control strategies. This study proposes a methodology for estimating rear-end crash potential, as a probabilistic measure, in real-time based on the analysis of vehicular movements. The methodology presented in this study consists of three components. The first predicts vehicle position and speed every second using a Kalman filtering technique. The second estimates the probability for the vehicle's trajectory to belong to either 'changing lane' or 'going straight'. A binary logistic regression (BLR) is used to model the lane-changing decision of the subject vehicle. The other component calculates crash probability by employing an exponential decay function that uses time-to-collision (TTC) between the subject vehicle and the front vehicle. The result of this study is expected to be adapted in developing traffic control and information systems, in particular, for crash prevention.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.49-56
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• 2011

Understanding various casual factors affecting the occurrence of freeway traffic crash is a backbone of deriving effective countermeasures. The first step toward understanding such factors is to identify crash risks on freeways. Unlike existing studies, this study focused on the unsafe vehicle maneuvering that can be detected by in-vehicle sensors. The recent advancement of sensor technologies allows us to gather and analyze detailed microscopic events leading to crash occurrence such as the abrupt change in acceleration. This study used an accelerometer to capture the unsafe events. A set of candidate variables representing unsafe events were derived from analyzing acceleration data obtained by the accelerometer. Then, the crash risk was modeled by the binary logistic regression technique. The probabilistic outcome of crash risk can be provided by the proposed model. An application of the methodology assessing crash risk was presented, and further research items for the successful field implementation were also discussed.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.93-99
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• 2020

A majority of car crash is affected by careless driving that causes extensive economic and social costs, as well as injuries and fatalities. Thus, the research of precise crash detection systems is very significant issues in automotive safety. A lot of crash detection algorithms have been developed, but the coverage of these algorithms has been limited to few scenarios. Road scenes and situations need to be considered in order to expand the scope of a collision detection system to include a variety of collision modes. The proposed algorithm effectively handles the x, y, and z axes of the sensor, while considering time and suggests a method suitable for various real worlds. To reduce nuisance and false crash detection events, the algorithm discriminated between driving mode and parking mode. The performance of the suggested algorithm was evaluated under various scenarios, and it successfully discriminated between driving and parking modes, and it adjusted crash detection events depending on the real scenario. The proposed algorithm is expected to efficiently manage the space and lifespan of the storage device by allowing the vehicle's black box system to store only necessary crash event's videos.

• Journal of Auto-vehicle Safety Association
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• v.15 no.3
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• pp.59-65
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• 2023

As advanced driving assistance system (ADAS) and autonomous driving performance continue to improve, existing crash accidents and crash types are changing. Accordingly, the collision angle and the seating posture of the occupant are changed. It is necessary to study how the occupant injury mechanism changes according to these different crash types. In this regard, a representative crash test mode was derived when the automatic emergency braking system (AEB), one of the autonomous driving performance, was applied to the representative car-to-car crash scenario in Korea. The derived crash test mode was used to analyse the mechanisms of collision injuries according to both impact angle and the occupant seating posture (reclined seat-back angle). The results obtained through this study can be utilized as reference data for the development of new crash evaluation methods and improvements in crash restraint systems for enhancing crash safety.

• Journal of Auto-vehicle Safety Association
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• v.5 no.1
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• pp.16-24
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• 2013

Some GM (General Motors) vehicles are using a GMLAN (General Motors Local Area Network) communication protocol for control and diagnostics. The airbag control module uses vehicle speed information from the GMLAN to record the vehicle speed as pre-crash information. In order to use the vehicle speed information for crash reconstruction purposes, it helps to be able to understand the accuracy of the data. The actual vehicle speed is not expected to be the same as the GMLAN indicated speed in some situations like a spin or if there is hard braking. This paper compares the actual vehicle speed and vehicle speed information during specific vehicle maneuvers. Actual vehicle speed is calculated from a GPS sensor, while GMLAN vehicle speed is calculated from transmission output sensor by the Engine control module (ECM). Vehicle maneuvers defined as Mode #1, Mode #2, Mode #3. The Mode #1 maneuver simulates wheel lock-up and skidding f by hard-braking at a specific speed. The Mode #2 maneuver simulates a 90degree turn using a J-turn maneuver at a specific speed. The Mode#3 maneuver simulates a 180 degree turn using a spin type of maneuver at a specific speed. The study then compares the GMLAN speed and GPS speed to see what speed difference exists between them. The results of this paper are applicable to GM vehicles only. This paper catalogs the performance and limitations of two vehicles as useful reference for crash reconstructions where there is a need to understand the speed indicated in the pre-crash section of the SDM data.

• Journal of Power System Engineering
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• v.6 no.3
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• pp.42-48
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• 2002

Velocity change of crashed vehicle has been applied to assess the safety of passenger and degree of impact severity widely. In this study, 1 D crash analysis and 2 D crash analysis were performed for velocity change of crashed vehicle with HVE 2D, and factors used for these analysis are weight, C.G, roll resistance, stiffness and brake force which influence on velocity change of crashed vehicle. According to results, the velocity change of crashed vehicle was influenced by weight, center of gravity stiffness and brake force but not roll resistance.

• International Journal of Highway Engineering
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• v.14 no.4
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• pp.113-124
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• 2012

PURPOSES : In This study two different concrete barrier systems have been proposed to be established at the small vehicle driveway. One is for median barrier, and the other is for roadside barrier. METHODS : In order to determine the suitable shape of barrier, the impact parameters including vehicle weight, impact angle, impact velocity and impact level have been analyzed. The real crash test has been carried out with 0.9 ton and 2.5 ton vehicles, respectively by using the 2m segment type concrete barriers connected by steel plates that are totally 40m barrier systems. RESULTS : The numerical results obtained by LS/DYNA-3D software are compared with real crash tests from the viewpoints of vehicle stability, vehicle trajectory, occupant risk, etc. CONCLUSIONS : From the above results, the dynamic performance of proposed barrier systems satisfies the specification of Korean Code for roadside safety structures.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.153-161
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• 2002

This paper develops a finite element model for crashworthiness analysis ova small-sized bus. The full vehicle finite element model is composed of 31,982 shell elements,599 beam elements,42 bar elements, and 34,204 nodes. The model uses four material models (such as elastic, elastic-plastic(steel), rigid. and elastic-plastic (rubber) material model) of PAM-CRASH. The model uses four contact types to define sliding interfaces in ten areas. A frontal crash test using an actual vehicle with 30mph velocity to a rigid barrier is carried out. Vehicle pulses at lower part of left and right b-pillar are measured, and deformed shapes of frame and driver seat's lower left area are photographed. A frontal crash simulation using the developed full vehicle finite element model is performed with PAM-CRASH installed in super computer SP2. The simulation is performed with the same conditions as the test. The measured vehicle pulses and photographed deformed shapes from the test are compared to ones from the simulation to validate the reliability of the developed model.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.6
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• pp.612-618
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• 2012

In this paper, in order to prevent electric shock of high voltage system of HFCV after crash test, insulation performance measurement methods were studied. Under conditions of in-use, insulation performance tests can be divided into measurement method using the vehicle's own RESS as DC voltage source and measurement method using DC voltage from off-vehicle sources. However, these tests can not be applied after a post-crash because parts of high voltage system cover should be removed, and insulation performance can be influenced during these tests. Therefore, we proposed post-crash insulation performance test methods for preventing electric shock through problem analysis of previous post-crash insulation performance tests. Also, test equipment which can measure voltage absence and total energy was developed. We verified performance of the equipment through experiments with vehicle test.

• Journal of Auto-vehicle Safety Association
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• v.6 no.2
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• pp.49-54
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• 2014

Development in vehicle industry could increase interest in children's safety recently. However the research of children safety is not being conducted as many as that of adult's. Especially the basic study for the vehicle crash on-board children was not much. This study focused on the effect of seatbelt anchorage points to evaluate children's safety in frontal crash. The current regulation of the seatbelt anchorage points is suitable for ranged from female 5% to male 95%. The assessment of children's safety at buckle up of no used CRS(child restraint system) was performed using frontal sled tests. The frontal crash pulse in sled tests was designed to the average of about 30 KNCAP frontal crash pulses. To reduce number of experiments, DOE is used. The Q6 child dummy and standard seat in UN R 129 were used. According to the analysis of test results, children's safety has been influenced by the points of seatbelt anchorage.