Crash Test Analysis

When reconstructing vehicle to vehicle collisions, it is often necessary to perform a damage energy analysis. This damage energy analysis is performed by using validated engineering techniques and various computer programs to compare the damage seen on an accident vehicle to that seen on a crash tested vehicle. This comparison to the known crash test data allows a detailed and accurate determination of crash severity and therefore reconstructed speed. KEVA Engineering has a library of thousands of US Government compliance crash tests. Our extensive crash test library covers front, rear, side impact, and rollover crash tests with vehicles from 1950 up through the 2000 model year.

Narrow Object Impacts

Narrow object impacts present special challenges to the accident reconstructionist. Energy absorption characteristics of vehicles struck by narrow objects differ from conventional car to car and barrier collisions. KEVA Engineering has analyzed numerous narrow object impacts and have also published original research into accident reconstruction methodologies when faced with these unique collisions.

Rollover Analysis

Rollover accident reconstruction requires a careful analysis of the vehicle damage, scratch directions, roll distance and pre-trip vehicle dynamics. Roll distance assists with vehicle speed determination. Scratch directions and vehicle deformation patterns allows the determination of roll over dynamics. Pre-trip vehicle dynamics allows the determination of the causal factors that led to the rollover. Rollover dynamics can be very important to understand vehicle and restraint system performance and injury potential.

Heavy Truck Collisions

Heavy vehicle rollover collisions present special cases that often involve allegations of mechanical failure leading to rollover. In this specific case shown, the front axle u-bolt was alleged to have failed, causing the rollover. However, careful examination of the scene and vehicle evidence indicates that the failure was a result of the rollover and was not the cause. Rather, the cause was due to excessive speed on the part of the driver. Photos show the pavement gouges made by the right front wheel after rollover and the sharp deviation caused when the u-bolt fractured. Photos also show the fractured u-bolt which indicates a single point overload failure with zero evidence of slow crack propagation or fatigue.

Minor Impact Analysis

The reconstruction and analysis of low impact collisions requires a careful analysis of the vehicle damage, the bumper capability, and the impact alignment between the two vehicles. With the specific case of a vehicle equipped with isolators, small energy absorbing struts to which the bumper is mounted, examination of these struts will usually yield evidence of stroking as small scratches and abrasions on the isolator tube. This isolator stroking evidence is visible even though there may be no external visible damage to the vehicle. Measurements of the scratches allows comparison to be made with staged collision testing and the impact to be reconstructed very accurately.

Minor Impact Analysis - Pickups and Sport Utilities

Pickups, vans, and sport utility vehicles (MPV's) are not required to meet the requirements in U.S. Government bumper standard, Part 581 of the Federal Motor Vehicle Safety Standards (FMVSS). Subsequently, MPV's, therefore, have bumper systems that are mounted directly to the vehicle frame with metal bracketry. This metal bracketry bends and permanently deforms to absorb energy. This bending can often be seen as a slight downward rotation to the rear bumper of a pickup truck. Generally, this bending and deformation occurs at much lower impact severity than passenger cars that must meet the Federal bumper standard. Subsequently, we often see significant damage to MPV's at quite low impact severity.

Bulb Filament Analysis

The examination and analysis of headlight and taillight filaments can often provide valuable information regarding the causal factors that led to a collision. Filament examination involves careful inspection and photography of the filaments found in the bulbs. When a filament is on, it is at an extremely high temperature and becomes malleable. Subsequently, when an impact of sufficient force occurs, the hot metal filament stretches. This stretched filament is then observed after an impact as evidence that the bulb was on during the impact. The reader should also keep in mind that while a filament that exhibits "hot stretch" was most likely on during the collision event, a lack of hot stretch does not automatically indicate the bulb was off. Rather, the bulb may not have been exposed to sufficient acceleration to cause "hot stretch" even though it was on during the impact. Additionally, a filament may demonstrate a cold break that indicates at the time the filament fractures, the filament was not hot. Cold breaks also do not occur in every instance. KEVA Engineering personnel have conducted numerous collision experiments with bulbs on and off and have performed detailed study into this methodology. The photograph shown is from an accident vehicle. The bulb examination demonstrates hot stretch from the low beam filament and no hot stretch from the high beam filament. The high beam filament also does not exhibit a "cold break."