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A study was conducted in order to assess the ability of tablet computers and GPS surveying equipment to measure vehicle kinematics. Although designed for other purposes, these devices have advanced electronics and data capture abilities that can be used to record a history of position data in four dimensions (x, y, z, and time). Many users of this type of equipment might not be aware of this. In contrast, several currently accepted devices for measuring and relating vehicle position, velocity, acceleration, and time are capable of only uniaxial and/or unidirectional measurements. Through a series of simple experiments, vehicular motion was generated through in-line braking to a stop, driving in a circle, and braking to a stop in a curve.

Problems with commercial motor vehicle components such as service brakes, steering controls, lighting devices, reflectors, tires, coupling devices, and other equipment can lead to accidents. Following a collision, accident reconstructionists may be called upon to determine whether these conditions were present before the crash and whether they were a causative factor. The paper gives an overview of current requirements of the Federal Motor Carrier Safety Regulations (FMCSR)(1) and Commercial Vehicle Safety Alliance (CVSA) that are related to daily vehicle inspections and commercial vehicle maintenance. Examples are presented to show how post-accident examinations detected vehicle deficiencies that were overlooked in the driver's vehicle inspection and/or fleet maintenance procedures. A discussion is included as to how such findings may be integrated into a reconstruction and cause analysis.

Commercial vehicle air brake systems are associated with more heat problems than hydraulic brake systems on passenger vehicles. A typical commercial vehicle runaway involves a driver who has lost the ability to control the speed of his vehicle and runs off the road because of too much speed in a curve or collides with slower moving vehicles. In some cases the driver has the ability to control speed to some extent and is unaware that he has overused the brakes until faced with a situation requiring a heavy brake application. The loss of braking capacity on long steep downgrades is due to the combined effects of heating, brake system design, friction material properties, maintenance, and brake adjustment. Brake drums expand as temperatures increase causing the strokes of the pushrods to increase. Brakes that are out of adjustment or at the limit of adjustment before heating can lose effectiveness with less heating than properly adjusted brakes.

This paper will give an overview of the information available from different types of vehicle data recorders, and ways the data can be used in the analysis of vehicle collisions. Reference will be made to current research relating to Event Data Recorders (EDR's). The methods used in downloading the data will be presented. Preservation of this evidence and admittance into court will be discussed. Traditional uses of this data in the determination of collision severity, seat belt use or non-use, and supplemental restraint system functionality will be discussed. Examples will be provided of additional, less traditional, uses involving the correlation of data recorded by EDR's during collision events with the results of reconstructions based on accident scene and vehicle crush data. Topics will include Delta-V, pre-crash vehicle motions and operation, driver perception/reaction times, driver actions, and vehicle acceleration/deceleration.

While Delta-V has been one of the most used indicators of accident severity for vehicle occupants, its actual determination remains a mystery to many who refer to it and use it. Delta-V is a term of art applied to a rapid change in vehicle velocity caused by impact forces during a collision. The Delta-V is associated with the high decelerations, which cause it and are applied to the occupants through restraint systems and collisions with the interior of the vehicle. This paper will serve as a primer for those new to the subject and a review for those who are familiar with the subject. Previous works by the authors will be referenced and other pertinent literature and data sources will be discussed. The analytical methods and test data used to calculate Delta-V will be presented and the relationship between Delta-V and other measures of impact severity, such as Barrier Equivalent Velocity and Energy Equivalent Speed will be discussed. The use of air bag sensor data will be included.

HVE 1 and PC-Crash 2 have been the subject of numerous SAE papers. Both programs have been offered to reconstructionists for the purpose of analyzing vehicle accidents and presenting the resulting motions in 3D graphical form. This paper will give an overview of the theoretical basis for the two computerized accident reconstruction and simulation tools, the user interfaces, the way they present the results, and how they compare in the analysis of different types of accidents.

Computer simulation and animation are used to build upon traditional methodologies for the evaluation of rollover accidents. The use of computer simulation allows for a more complete and detailed reconstruction than is possible with traditional methods. The use of computer animation allows a superior presentation of the reconstruction with detailed analytical results and real time visualization employing 3-D computer graphics. The accident scene and vehicle damage data are used together with results from rollover tests and computer simulation and computer graphics to reconstruct the vehicle path and vehicle dynamics in three dimensions. The significant previous papers, which provide the scientific basis for rollover accident reconstruction, are discussed with regard as to how this knowledge can be applied using HVE1 and 3-D Studio MAX2.