The Goldhaber Warnings Report: This past weekend as Hurricane Bill brushed past the Eastern Coast Line of the United States, bringing dangerous riptides to our shores, police and lifeguards posted explicit warning signs (reinforced by nonstop media coverage about the dangers of these riptides) closing beaches from North Carolina throughout New Jersey, New York and New England. Despite this barrage of warning and safety information, who can forget the televised images of the hundreds of apparent daredevils, mostly young men, ignoring the warnings and entering the beaches to look at the waves, and even swim or surf in the turbulent waters!
Airbags are credited with reducing numerous injuries and saving many lives during vehicle accidents. However, there have been incidents where they do not function as intended, and have even caused injuries such as explosive powder burns, detached eye retinas, child suffocation and impact deaths.
Persons with no training in engineering are generally unaware of the nature of engineering analysis, and so tend to assume that testing, as a means of determining the causation of accidents, is a dominant tool of the engineer. In the following examples, we shall undertake to explain the nature of engineering analysis, and to show that it is more basic than testing because testing without analysis is meaningless. Further, while analysis is always necessary in accident reconstruction, testing is only sometimes necessary.
Second to automobile accidents, accidents due to falls are the leading cause of injury and death. Of these, accidents due to slipping (not tripping) form a large proportion. Slipping may occur on floors, walkways, and stairs or steps. For Introductory purposes, however, the present discussion will be limited to slipping on flat surfaces such as a floor or sidewalk.
When a person becomes aware of a dangerous situation, a time-interval must elapse before he can take defensive action against it. This time interval, commonly called the reaction time, has been found to be about 0.7 second for all normal persons, regardless of their background and training. This suggests that the reaction time depends on some basic aspect of the human physiology-involving the brain, nervous system, and muscles-which does not vary much from person to person.
A car is stopped for a light when it is unexpectedly rear-ended by a vehicle from behind. It is not a hard impact and there is little or no damage to either vehicle, because the energy absorbing bumpers have protected them. Nevertheless, the passengers of the struck vehicle complain of neck, shoulder and back pain. The next day they allegedly experience even greater pain and visit a medical person who claims that they have been injured. Insurance claim representatives, attorneys, medical, engineering and biomedical experts are then brought in and various conflicting allegations, testimony and opinions are expressed. Do we have a legitimate injury claim on our hands or a situation of fraud?
Accident reconstructionists are often called on to determine the distance that a car, covers while being braked to a stop. Conversely, the reconstructionist may be given information as to the length of the skidmarks left by a car on the roadway, and may be asked to determine how fast the car must have been going at the beginning of the skid. An expert can accomplish this with considerable accuracy, based on a knowledge of the physical principles that are involved, plus available information relating to the friction of tires on various types of road surfaces.
According to the Consumer Products Safety Commission (CPSC), there are approximately 10,000 golf car related injuries requiring emergency room treatment in the US each year. One significant mode of injury in golf car accidents is passenger ejection, which can lead to serious injuries, especially of the head. Based on CPSC statistics, roughly 35% of golf car accidents involve a person falling out of the car. In addition to ejection accidents, at least 10% of golf car accidents involve a rollover and statistics indicate that such accidents are roughly twice as likely to lead to injuries requiring a hospital stay as non-rollover accidents.
According to Consumer Product Safety Commission (CPSC) accident estimates, tens of thousands of stepladder accidents requiring emergency room treatment occurred annually in the United States. Approximately 85-90% of these accidents involve the user falling from the ladder and 8-9% of these injuries are serious enough to require that the victim be admitted to a hospital. In addition to posing a severe health concern, these accidents have significant loss-of-wages and high medical expense implications.