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There have been a number of papers written about the dynamic effects of low speed front to rear impacts between motor vehicles during the last several years. This has been an important issue in the field of accident analysis and reconstruction because of the frequency with which the accidents occur and the costs of injuries allegedly associated with them. Sideswipe impacts are another, often minor, type of motor vehicle impact that generate a significant number of injury claims. These impacts are difficult to analyze for a number of reasons. First, there have been very few studies in the literature describing the specific dynamic effects of minor sideswipe impacts on the struck vehicles and their occupants. Those that have been performed have focused on the impact of two passenger cars.

The Federal Side Impact Test Procedure prescribed by FMVSS 214, simulates a central, orthogonal intersection collision between two moving vehicles by impacting the side of the stationary test vehicle with a moving test buck in a crabbed configuration. While the pre- and post-impact speeds of the vehicles involved in an accident can not be duplicated using this method, closing speeds, vehicle damage, vehicle speed changes and vehicle accelerations can be duplicated. These are the important parameters for the examination of vehicle restraint system performance and the prediction of occupant injury. The acceptability of this method of testing is not as obvious for the reconstruction of accidents where the impact is non-central, or the angle of impact is not orthogonal. This paper will examine the use of crash testing with a single moving vehicle to simulate oblique or non-central collisions between two moving vehicles.

Adequacy of resistance spot welds in low carbon steels in relation to structural integrity can become an issue in the reconstruction of automotive accidents. Because formation of a plug (or button or slug) in a peel test is used as a quality control criterion for welds, it is sometimes assumed conversely that a weld which failed is defective if no plug is present. Spot welds do not necessarily form a plug when fractured. Fracture behavior of spot welds both by overload and fatigue is reviewed. Then techniques for examination of field failures are discussed. Finally two case histories are discussed.

It is commonly recommended to use infant/child restraints in the rear seat, and that until an infant reaches certain age, weight and height criteria, the infant restraint should be placed rear facing. This paper will describe the injuries suffered by an infant that was restrained in a forward-facing child seat placed in the front passenger seating position during a real world collision. Based on this collision, a full-scale vehicle to barrier impact test was performed. For this test, two 6-month-old CRABI dummies were used in identical child restraints. One of the restraints was placed in the front passenger seat in a forward facing configuration, and the other was placed in the right rear seating position in a rear-facing configuration. This paper provides a detailed discussion of the results of this test, including comparisons of the specific kinematics for both the restraint/child dummy configurations.

Taillight lamp filaments provide valuable information on their illumination status during a collision. This information is contained in the shape of filament deformation, extent and nature of filament fracture, and filament oxidation. The degree of deformation of these filaments, a quantity which may be useful in determining velocities prior to impact, has been documented for headlights but has not been closely examined for taillights. In this paper, a study of the quantification of automobile taillight filament response when subjected to low speed impacts is presented. These studies include two different brands, five velocities up to approximately 19 miles per hour, three filament orientations, and two different deceleration pulses. Recommendations are given for further study in order to provide sufficient data for practical application and use in accident reconstruction.

The use of vehicle damage measurements has been proven to be an effective technique in the determination of impact energy and pre-collision speeds. However, as with any analytical technique, the quality of the speed estimate is highly dependent on the accuracy of the measurements. This relationship suggests a need to employ intricate and exacting measurement schemes to obtain useable data. This approach is often difficult to implement in a routine accident investigation where a tape measure may be the only available measuring device. In the current study, vehicle damage resulting from collisions with a known speed is measured with techniques of increasing sophistication and the results are compared. These measurements are then used in conjunction with the CRASH III computer program to estimate the pre-impact vehicle speeds. The analysis technique used by CRASH III is also reviewed to provide a summary understanding of how the crush measurements are used in the program.

ORVR (Onboard Refueling Vapor Recovery) canisters trap vapors during normal operations of a vehicle's engine, and during refueling. This study evaluates the relative risks involved should a canister rupture in a crash. A canister impactor was developed to simulate real-world impacts and to evaluate the canisters' rupture characteristics. Numerous performance aspects of canisters were evaluated: the energy required to rupture a canister; the spread of carbon particles following rupture; the ease of ignition of vapor-laden particles; the vapor concentration in the area of ruptured, vapor-laden canisters; and the potential of crashes to rupture and ignite canisters. Results from these five items were combined into a risk analysis.

A technique has been developed to study the effects of the vehicle interior on the performance of child safety seats. Child safety seat sled tests are used to define the kinematics of the seat and child in a crash situation. Computer animation of this motion is superimposed on the motion of the actual vehicle crash tests giving an estimation of the kinematics of the child and child seat in a real crash situation. The significance of the vehicle interior and the interference of the vehicle interior with the child's kinematics is presented within the computer animation. The analysis is conducted using a single child restraint device in multiple seating conditions within a single vehicle.

The Suspension Parameter Measurement Device Model 7547 (SPMD Model 7547) has been designed and built for the purpose of measuring displacements and forces acting on the road wheels of a vehicle. These displacements and forces may be due to movement of the vehicle body (kinematic), forces occurring in the plane of the road (compliance), or due to movement of the steering wheel (steering). The SPMD Model 7547 tests the entire vehicle as a unit and provides a “black box” determination of the suspension characteristics in terms of input/output relationships. This data can then be used in the simulation of the performance of light cars and trucks.

There have been a number of papers written about the dynamic effects of low speed front to rear impacts between motor vehicles during the last several years. This has been an important issue in the field of accident analysis and reconstruction because of the frequency with which the accidents occur and the costs of injuries allegedly associated with them. Several of these papers have discussed the importance of the coefficient of restitution in the accelerations and speed changes that the vehicles undergo in such impacts. These discussions often include data showing the measured restitution for impacts involving various bumper types and closing speeds. However, in most of these studies, the impacts are controlled so that direct bumper to bumper impacts occur. This paper will present the results of several rear impact tests with non-standard impact configurations.

During the past few years, the National Highway Traffic Safety Administration's (NHTSA) Vehicle Research and Test Center has generated a plethora of reliable vehicle test data during their efforts to study vehicle rollover propensity. This paper provides further analyses of a small selection of some of the data. The analyses provided here derive in part from the previous work, trying to answer some of the questions spawned by earlier analyses. The purpose of this paper is to introduce several new concepts to the study of vehicle roll stability and provide case studies using the results available from the NHTSA testing. Results from several severe maneuvers are studied in detail to gain understanding of vehicle response in these cases.

This paper presents an overview of the evolution of computer simulations in vehicle collision and occupant kinematic reconstructions. The basic principles behind these simulations, the origin of these programs and the evolution of these programs from a basic analytical mathematical model to a sophisticated computer program are discussed. In addition, a brief computer development history is discussed to demonstrate how the evolution of computer assisted vehicle accident reconstruction becomes feasible for a reconstructionist. Possible future research in computer reconstruction is also discussed.

The advent of the Hybrid III crash test dummy marked the beginning of biofidelic anthropomorphic test devices. During the development of its critical components, notably the head, neck, knee, and thorax, biomechanical cadaver test results were incorporated into the design. The result was a dummy that represented the 50th percentile male during idealized impacts. In order to achieve a more biofidelic response from the components, many exotic materials and unique designs were utilized. The thorax, for instance, incorporates a spring steel rib design laminated with a viscoelastic polymeric composite material to damp the response. This combination results in the proper hysteretic losses necessary to model the human thorax under impact loading conditions. The disadvantage of this design is that the damping material properties are highly sensitive to temperature. A variation of more than 5 degrees Fahrenheit dramatically affects the response of the thorax.