When a low speed crash occurs between two vehicles, evaluation of the conditions of the crash, assessment of fault, determination of velocity change, or calculation of forces and accelerations acting on the vehicles and the occupants may be required. After engineering and biomechanical analysis of the crash has been completed, the force levels generated in the particular crash may not appear to agree with the nature and severity of the claimed injuries.
The applied vehicle forces that occur during impact between two vehicles are governed by the laws of physics. Crash injury protection is governed by known and established human tolerance values to both inertial and impact forces and restraint system design. This paper will focus on the fundamental methods of analysis for the low-speed impact. The first step will consider analysis of the actual mishap itself, and the analytical methods for quantifying the force levels applied to the vehicle during the crash. The second part will evaluate the reported injuries from an occupant protection and biomechanical approach.
There are times when it becomes necessary to identify the mechanism of the injuries claimed to be caused by a low-speed impact. This may be required because the claimed injuries do not appear to conform to the physics of the actual impact. Risk managers, safety, claims, and loss prevention professionals deal with property damage and bodily injury claims routinely which are alleged to have resulted from low-speed vehicle collisions. In some cases the claimed injuries do not comport with the description of the accident.
The applied vehicle forces during any impact are governed by the laws of physics. Crash injury protection is governed by known and established human tolerance values to both inertial and impact forces and restraint system design. For an injury to occur requires both, 1) a magnitude of force that exceeds human tolerance, 2) and a mechanism known to produce injury.1 This paper will focus on the fundamental method of analysis of the low-speed impact. The first step will consider analysis of the actual mshap itself, and the analytical methods for quantifying the force levels applied to the occupants during the impact. The second step will be to conduct a biomechanical analysis of the specific injuries to determine whether there was an injury mechanism present during the subject impact.
For the purposes of this paper, a low-speed impact will be classified as an impact at or below a 10 mph change in velocity (delta-V). Oftentimes the crash speeds are much lower than this value. In fact, in many low-speed impacts, the damage cited is in the form of scratches, scrapes, or minor deformation. Underlying damage beneath the scratches and scrapes is minimal, with deformed brackets, shock isolators, bumper bars or foam being cited as the main items needing repair or replacement. The majority of low-speed impacts are typically drive-away accidents. Common accident reconstruction methods and techniques cannot always be used. Oftentimes there is no, or little, measurable crush to the mishap vehicles.