The risk of sustaining an injury during a specific kind of crash can be calculated from real world accident data. We simply take the number of injured individuals following a crash and divide this by the number of individuals exposed to this kind of crash. The resulting number, expressed as a percentage, is the a […]
It’s common knowledge that a helmet should be replaced after a significant impact. Exposure to extreme heat or chemicals, like gasoline, ammonia and solvents, can also degrade a helmet. But aside from impact, heat or chemical damage, does a helmet need to be replaced just because it is old? Do the impact attenuating properties of […]
Roadside guardrails make our roads safer, but the ends of these guardrails need protection, or end treatments, to prevent them from becoming roadside hazards of their own. Recent court cases involving some end treatments have focused media and public attention on the potential hazards associated with these special features of guardrails. The ends of guardrails […]
A driver who fails to avoid a roadway hazard, such as a pedestrian, cyclist or other car, could have his pre-crash responses closely scrutinized if the crash is investigated. Driver responses are generally scrutinized in three ways: 1) response speed, 2) response choice, and 3) response magnitude. Response Speed The time it takes a driver […]
Drivers predictably encounter the unpredictable. Whether as benign as a newspaper blowing across the road or as serious as a child darting from the curb, drivers must decide what to do when confronted with these situations. In the case of the blowing newspaper, a driver may decide to do nothing, whereas in more serious situations, […]
When an aircraft accident occurs, everyone wants to uncover the underlying causal and contributory factors; in other words, the why. After careful examination of all available information in an aviation accident investigation, a skilled human factors expert can render educated opinions regarding a wide range of issues, from duty of care considerations to external influences […]
Among the pilot’s last words on Air France 447 that crashed in the Atlantic in 2009 were “This can’t be happening”, denying the tragic fact that there is no chance of survival on an aircraft that experiences a catastrophic malfunction at cruise altitude. There is always hope for survival in land and sea accidents, because […]
Of the four consumer products in the figure above, one does not belong. Which one is it? The disposable propane cylinder is made of steel and holds liquid petroleum gas, which is a two-phase mixture of liquid and gaseous propane. At normal indoor temperatures the pressure inside the container, called its internal pressure, is about […]
Like most other injuries, concussions occur in the blink of an eye. Unlike most injuries, however, concussions can occur without leaving a physical mark. Even when a concussion is diagnosed, the question may remain whether the event alleged to have caused the concussion was indeed responsible. From a biomechanical perspective, it is sometimes possible to […]
When a vehicle strikes a pedestrian at night, assessing the driver’s liability may hinge on characterizing the visibility of the pedestrian. Quantifying pedestrian visibility, however, is not simple. Photographs, which can more accurately depict visibility in daylight, have severe limitations depicting visibility at night. Photographic media (films and digital sensors) have different color and light […]