Below is a summary of some of the latest research regarding injuries related to low and high speed collisions. This information is re-posted with permission from Dr. Jay Morgan. Some commentary and explanation in red has been added throughout the article.
LOW IMPACT CRASH RESEARCH
Science and statistics say that long term whiplash injuries occur more often in low energy crashes. There is a unique phenomenon that occurs between high and low speed crashes.
High Speed Crashes:
HIGH RISK FOR:
- Abdominal and chest injuries
LOW RISK FOR:
- Cervical and lumbar disc injuries
- Spinal ligament injuries
- Vestibular (related to balance) injuries
-Except for lower extremity fractures, most injuries heal without significant disability. High energy crash fatalities and injuries are decreasing each year.
Low Speed Crashes:
Whiplash is a very common injury in low speed collisions.
HIGH RISK FOR:
- Spine injury
- Ligament injury
LOW RISK FOR:
- Abdominal injury
-Many injuries never heal completely and there is an increased risk for chronic pain and fatigue by 25%. WHY?
NEW VEHICLES ARE DESIGNED TO PROTECT THE OCCUPANT IN HIGH SPEED CRASHES.
-crush zones, safer seatbacks, air bags, improved belt restraints
-all of these create a plastic crash (non-elastic crash in which the energy is transferred to the occupants from the vehicle).
-the more plastic the crash, the longer the ride down
-the longer the ride down, the less the “g” forces
-the lower the “g” forces, the less the risk of injury
NEW VEHICLES ARE DESIGNED TO PROTECT THE VEHICLE IN LOW SPEED CRASHES
-there is no concern for occupant safety
-risk of death is the current goal in auto safety
-low speed crashes have minimal risk of death therefore, occupant safety has not been an issue
MAIN CONCERN IS ZERO VEHICLE DAMAGE
-even though the legal requirements for manufactures are stated as public safety needs, they are only designed to protect the vehicle
-insurance carriers don’t want to pay to fix millions of vehicles involved in low speed crashes every year
-this creates a very elastic crash
-two key factors of an elastic crash: the more elastic,
- the higher the delta V (energy needed to change speeds)
- the less time the crash takes
G-forces similar to the ones shown in this image occur in a split second in rear-end collision and can cause serious damage to soft tissues.
-the less time the crash takes, the less the ride down
-the less the ride down, the higher the “g” forces
-the higher the “g’s” the greater the risk for injuries
VEHICLE DAMAGE AS IT RELATES TO OCCUPANT INJURY
The relationships between the severity of vehicle damage and to occupant injury have been researched many times. They always come to only one conclusion. IT CANNOT BE DONE!! Bailey et al commented that “in a rear end impact, many vehicles will be undamaged at crash severities that are above the range where human volunteers have reported neck and back symptoms.” In other words tests have shown that people riding in the car can suffer significant injuries and the vehicle will show little or no damage.
PARADOXIC RELATIONSHIP: previous attempts to correlate vehicle damage to occupant injury has failed to show a relationship. However due to the elastic nature of low impact collisions, the apparent paradox of the inverse relationship between property damage and injury potential is a real one. Walz and Muser concluded that “the greater the vehicle damage, the less the biomechanical loading, and the inverse.” Outcome studies have also not shown a significant relationship between crash damage and injury severity in rear impact collisions. For example, recently Radanov et al reported finding no differences in outcome between crash severity assessment groups. Often the more damage suffered by the car the less damage to the occupants due to the fact that the car absorbed most of the impact (think of Nascar car where the car is destroyed but the driver gets up and walks away). Conversely, the less damage suffered by the vehicle the more injury to the occupant since the energy was transferred from the car to the person.
Some cars are designed to take the impact, often leaving the occupant with less severe injuries.
While others are designed to transfer the damage away from the vehicle and to the occupant.
CAN YOU TELL IF THE DRIVER WAS INJURED BY THE LOOKS OF THE VEHICLE? CAN YOU EVEN TELL IF A VEHICLE WAS IN A REAR IMPACT CRASH? IF SO HOW MANY TIMES? HOW FAST? OR WHEN? EVEN MORE IMPORTANTLY HOW BAD WAS THE DRIVER INJURED? TO THESE QUESTIONS THE ANWSER IS “NO, YOU CANT!” EXTENSIVE RESEARCH HAS BEEN PERFORMED TO TRY TO CORRELATE VEHICLE DAMAGE TO THE OCCUPANT INJURIES. THE FINAL CONCLUSION IN ALL CASES IS: THERE IS NO CORRELATION. THE SOLUTION IS TO TAKE THE FOCUS OFF THE VEHICLE AND PUT THE FOCUS ON THE PATIENT.