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Through testing conducted by multiple facilities, it has been observed that the class of compact two-person vehicles designed exclusively for off-road operation known as Recreational Off-Highway Vehicles (ROVs) exhibit a range of steady-state handling characteristics - including both understeer and understeer transitioning to oversteer as measured in circle-turn tests similar to those set forth in SAEJ266. This handling characteristic is different from on-road passenger cars and light trucks which, under all but heavy loading conditions, exhibit linear range and limit understeer steady-state cornering behavior. Limit understeer is considered desirable for on-road vehicles because it provides a directionally stable and generally predictable control response. In the research presented in this paper, the handling qualities, including controllability, of a ROV which was modified to have different steady-state handling characteristics ranging from understeer to oversteer is examined.

Accident investigators are often required to determine if an occupant was using a seat belt during a collision. Substantial research has been conducted on the types of physical evidence generated on a seat belt by occupant loading during a collision. However, very little research has been conducted concerning the characteristics of physical evidence that is created when an occupant uses their seat belt improperly. Case studies with misused seat belts were reviewed showing tell-tales of atypical or improper restraint usage. Occupants also experienced injuries consistent with greater excursion and contact with vehicle interior surfaces. To compare the physical evidence of properly and improperly used restraints, automotive frontal sled tests were conducted with matched pairs of anthropomorphic test devices (ATD) with seat belts used both correctly and incorrectly. When the seat belt was used improperly, distinctly different marks were observed.

This paper describes an investigation that seeks to understand how rollovers occur in real-world crashes, both by studying real world crashes and by analyzing vehicle handling tests to gain insights into potential mechanisms of pre-crash loss of control. In particular, this study focuses on one type of rollover, namely single-vehicle rollovers that follow a pattern of the vehicle first leaving the roadway and then returning to the roadway typically out-of-control. Aims of this study included the following: To describe the frequency and characteristics of single-vehicle rollovers involving an off-roadway excursion followed by a complete, if only temporary return to the roadway. To the extent possible, given available data, to assess the nature and consequences of driver inputs during the crash sequence. To define characteristics of crash scenarios which include a substantial proportion of this subset of single-vehicle rollovers.

The relationship between pre-braking speed and the length of locked wheel skid marks has been explored in many publications. However, the existing literature does not address the effects of anti-lock braking on pre-braking speed calculations based on the length of tire marks. Anti-lock brake systems reduce the wheel slip and avoid wheel lock (100% slip) to enable a vehicle to achieve high deceleration rates under emergency braking while retaining steering control. Typically, during braking an ABS system will maintain 5-25% slip, and can sometimes leave faint and/or alternating tire marks as opposed to the dark skid marks created by a locked sliding wheel. Instrumented vehicle testing was conducted on a variety of vehicles to quantify the effects of pre-mark braking on overall speed change. From this data, the effective deceleration for the tested road surface was evaluated and compared to existing literature for locked wheel braking.

Accident investigators are often required to determine if an occupant was wearing their seat belt during a collision. Previous studies have provided examples of physical evidence relied upon by investigators to determine if the seat belt assembly was subjected to occupant restraint loading. This paper examines the potential for clothing fibers to be permanently transferred to the seat belt webbing during a collision. To evaluate fabric transfer evidence as an indicator of restraint usage by an occupant during a collision, the following issues were examined: automotive seat belt webbing construction and behavior under load, fiber evidence found on the webbing in new and used conditions, and the transfer of different types of clothing fibers to webbing during full-scale sled testing.

The results of a number of previous studies have demonstrated that seat-belted occupants can undergo significant upward and outward excursion during the airborne phase of vehicular rollover, which may place the occupant at risk for injury during subsequent ground contacts. Furthermore, testing using human volunteers, ATDs, and cadavers has shown that increasing tension in the restraint system prior to a rollover event may be of value for reducing occupant displacement. On this basis, it may be argued that pretensioning the restraint system, utilizing technology developed and installed primarily for improving injury outcome in frontal impacts, may modify restrained occupant injury potential during rollover accidents. However, the capacity of current pretensioner designs to positively impact the motion of a restrained occupant during rollover remains unclear.