Frontal Impact Crashworthiness Defects
In 2015, over 35,000 Americans were killed in automobile accidents. Studies estimate that over half of these fatal accidents are frontal and frontal offset impacts. These figures do not include the additional 10s of thousands of serious injuries as well that are the result of frontal impact accidents.
Fortunately, design improvements and advances in medical care are allowing many of the severely injured people to have a greater chance at survival, longer life expectancy, and improved spinal and head injury recoveries. Further design improvements geared towards a vehicles frontal crashworthiness are necessary for these figures to improve more.
One of the basic principles behind frontal impact accidents is the rapid deceleration of a vehicle. During a frontal collision, the vehicle and its occupants are suddenly put under rapid deceleration. It is during these fractions of a second that vehicle design becomes vital for survival. Modern day automobiles are made to be sacrificed during such an event to protect the passengers. A vehicles crashworthiness can be measured by examining how much time the vehicle allows for distribution of the deceleration, how much area does the vehicle allow the forces to be distributed through, and if human distribution is involved, distributing those forces to parts of the body that can withstand greater force.
Crash testing since the end of the 1970’s has helped manufacturers and government agencies like the Department of Transportation determine what areas of the body are more crash worthy. The electronic transmitters provide data for head injuries (HIC), chest injuries (Chest G) and leg injury (femur load).
The lower the numbers are, the better chance of escaping one of these injuries during a frontal impact accident. In properly designed vehicles, the crumpling effect allows a passenger to “ride the crash down” as a human body can normally not tolerate hitting a solid wall at 30mph or greater. Unbelted passengers experience the full effect of frontal impact accidents. During the crash, these unbelted occupants keep moving at the pre-impact speed. As a result, while the vehicle is crushing itself to protect belted occupants, those unbelted fly forward into the steering wheel, windshields, A-pillar, or other parts of the vehicle. This can cause more injury and death than the impact itself.
Though less common now than in previous decades, there are still design defects that enhance the risk of injuries during a frontal impact accident. Some of those defects that have been corrected by manufacturers include no longer using door mounted automatic belts and two point shoulder belts.
Door-mounted automatic belts fail in several ways. In the event a door opens during the accident, the door-mounted belts may fail to retain the occupant in the vehicle. Ejections are some of the most dangerous and injury laden effects of poor design. Crash testing and highway experience has shown that door latches have failed in various impacts and when these door latches fail, the doors open and the belts move away from the passenger. This design fails and frequently leads to partial or complete ejection with catastrophic injury or death. Some vehicles were even worse in that they did not include a lap belt or the user would not use a lap belt due to the “automatic” nature of the shoulder belt causing the occupant to submarine under the shoulder belt. Pelvic restraint is absolutely required to prevent this. Injuries resulting from the submarining are/were frequently spinal cord related. Fortunately, since the late 90’s, vehicles are no longer manufactured using passive belt systems and airbags with 3 point belt systems are now standard across all makes and vehicles.
Although motor vehicle safety has improved by leaps and bounds, the technology to do more to protect occupants during frontal impact accidents is available. Fortunately for both the good of the public and automobile makers business, safety is a top priority for car buyers.