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Snowmobile acceleration, braking and cornering performance data are not well developed for use in accident reconstruction. Linear acceleration and braking data published by D'Addario[1] gives results for testing on 4 snowmobiles of various make and model. This paper presents the results of on-snow tests performed in 2014 which include acceleration and cornering maneuvers that have not been published previously. Maximum and average cornering speeds and corresponding lateral accelerations are presented for turns of radius 20, 35 and 65 feet (6.1, 10.7 and 19.8 meters) on level, packed snow. Performance values for acceleration, braking, and cornering are determined in tests with and without a passenger. Results of linear acceleration and braking tests were found to be comparable to the previously published work. The data are useful in snowmobile accident reconstruction for certain types of snowmobile motion analyses.

This paper presents results of full-scale instrumented rollover testing on ROV type recreational vehicles. Five tests were conducted using two instrumented side-by-side ROVs at speeds between 20 and 32 mph on unpaved surfaces. Each test vehicle was brought to speed and released, allowing remote steering inputs to initiate turn sequences resulting in rollover. Accelerations were determined using x, y, and z axis accelerometers mounted at the vehicle CG and recorded using a robust data acquisition system. Roll rates were measured using a rotation rate sensor. Roll rates and key acceleration events are presented for each test. Mapping and measurement of the test site includes photography and digital survey of resulting tire marks, impact marks and gouging. Documentation and reconstruction of test roll sequences includes roll rates, vehicle positions and velocities, peak accelerations by impact, and scratch mark and damage examination. These are included in the appendix .

Vehicles involved in rollover accidents almost always leave a debris trail. This debris trail is useful for the accident reconstructionist; it assists with identifying the vehicle path during the rollover and the location and orientation of the vehicle at various vehicle to ground contacts. Often it is helpful to know when and where various vehicle windows fractured. This is possible by comparing glass obtained from the accident site with glass samples still attached to the accident vehicle. The limit of this analysis is controlled by the manufacturing tolerance of the vehicle glass and the specified pane thickness. This paper presents a series of measurements made on various automotive tempered windows and presents: 1) the thickness range in individual panes, and 2) the thickness variation seen from pane to pane in the same vehicle.

Initial claims that seatbelt buckles might inertially unlatch in an automobile collision were based upon the observation that sharply striking the backside of a side-release buckle with some object could cause the buckle to unlatch. More recently, similar examinations have formed the basis of the hypothesis that end-release buckles might be susceptible to inertial release under certain crash conditions. This paper discusses some examples of how test data have been misinterpreted to erroneously support these hypotheses.

Understanding occupant kinematics is an important part of accident reconstruction, particularly with respect to injury causation. Injuries are generally sustained as the occupant interacts with the vehicle interior surfaces and is rapidly accelerated to the struck component's post-impact velocity. This paper describes some methods for assessing occupant kinematics in a collision, and discusses their limitations. A useful technique is presented which is based on free-body analysis and can be used to establish an occupant's path of motion relative to the vehicle, locate the point of occupant contact, and determine the occupant's velocity relative to that contact location.

Rollover accidents often have a vast amount of information available for determining vehicle and occupant kinetics and kinematics. Physical evidence and photographs of the accident scene and vehicle can be used to determine trajectories, distances, velocities and orientations. The direction, angle, and chronological order of scrapes or scratch patterns and other directional indicators on the vehicle peripheral surfaces are typically used to reconstruct the vehicle orientation throughout the rollover sequence. Evidence from the scene and vehicle, however, can sometimes appear inconsistent, because they suggest a substantially different vehicle orientation at a particular contact point. An apparent inconsistency of this nature can often be corrected by accounting for the effects of vehicle roll velocity during surface contacts.

Markings or observable anomalies on seat belt webbing and hardware can be classified into two categories: (1) marks caused by collision forces, or “loading marks”; and (2) marks that are created by non-accident situations, or “noncollision marks”. In a previous work, a survey of the driver's seat belt of 307 vehicles that had never experienced a collision was conducted, and several examples of marks created by normal, everyday usage, or “normal usage marks” were presented. It was found that some normal usage marks were visually similar to loading marks. This paper presents several examples comparing loading marks to visually similar normal usage marks and discusses the important similarities and differences.

The assessment of seat belt usage during a collision is typically made by considering four types of evidence: (1) the nature and location of the occupant’s injuries, (2) the presence or absence of occupant contact marks in the passenger compartment, (3) the occupant’s final position and (4) markings on the restraint system. This paper focuses specifically on seat belt restraint system markings. Markings or observable anomalies on the webbing and restraint system hardware can be classified into two categories: (1) those caused by collision forces, or “loading marks” and (2) those created by noncollision situations, or “normal usage marks”. Some normal usage marks can appear visually similar to loading marks. The purpose of this paper is to help the investigator distinguish between occupant loading marks and normal usage marks by presenting examples of marks found on belt restraint systems that have never experienced occupant loading in a collision.