Bullet vs. Target Vehicles in Auto Accidents

Bullet vs. Target Vehicles in Auto Accidents

I’ve spoken to many friends and family members who have been involved in auto accidents in Baltimore. Some have accidentally caused the collision (the bullet vehicle) while others have been on the receiving end (target vehicle).  Almost universally those causing the crash end up saying “there’s no way that person could be hurt! I barely hit them!” On one hand they are likely concerned about their auto insurance rates rising as a result of a faulted motor vehicle collision, but on the other hand, they really can’t imagine the passenger’s in the other car being injured given the fact that they feel ok after the crash.

Dr. Arthur Croft sheds some light on this phenomenon in his book “Whiplash and Mild Traumatic Brain Injuries: A Guide for Patients and Practitioners.” His institute, the Spine Research Institute of San Diego, was the first to conduct an experiment that examined the difference between the forces experienced in a frontal crash (the bullet vehicle) and a rear-end impact (the target vehicle).

In his research he determined that the forces on the human subject’s necks were up to 4 times higher in the rear-ended vehicle than in the front impact vehicle. He also noted that subjects felt more of an impact when they were in the rear-ended vehicle than if they were in the bullet vehicle.

One major explanation as to why this is the case deals with preparation. The front-end impacted vehicle (bullet vehicle) typically can see the accident unfolding in front of them, allowing for even minor “bracing” in preparation which leads to less injury as compared to the unaware target vehicle’s occupants.

More interestingly the spinal kinematics are different between the striking and struck vehicle. In the bullet vehicle the driver experiences a “monophasic” response, in which he experiences a single forward bending motion as he is restrained by the seat belt and shoulder harness.

The target (rear-ended) vehicle’s occupants actually undergo a “biphasic” response. First, the seat back strikes the occupant from the rear, causing the curves of the spine to flatten. Then the pelvis and torso are accelerated forward by the seat, leaving the head momentarily at rest, causing the head to lag behind slightly before striking the head restraint. Once it strikes the head restraint, the head actually accelerates quicker than the rest of the body forcing it to rebound faster, and accelerate at a greater magnitude than that of the car or the pelvis or the torso. Then in the second phase, the occupants must actively resist forward motion aided by the seat belt by decelerating their forward head and body movement.

Dr. Croft’s mathematical analysis in the rear-ended vehicle is quite striking. He notes that if the rear-ended (target) occupant’s head were to be extended over a table she would feel the acceleration of 1g (earth’s gravity). Given that the average human head weighs 8-10 lbs, with a peak acceleration noted to be around 13g during a rear-end impact, it is the equivalent of a human head effectively effectively weighing between 102-128 lbs in a matter of 2 tenths of a second! Even knowing that a rear-end impact was pending (which most real-life occupants do not know) they CAN NOT under any circumstances actively brace themselves to prevent this level of acceleration in their necks.

Hence, it is clear that rear-ended occupants can and do experience more force in their spines than do the individuals in the car causing the collision in a front-end collision.

If you or anyone you know has been involved in an auto accident in Baltimore or the surrounding areas please contact Mid-Atlantic Spinal Rehab & Chiropractic at (443) 842-5500. Dr. Gulitz is a Baltimore Chiropractor specifically trained in the rehabilitation of auto accidents including whiplash and mild traumatic brain injuries.

More on Car Seats and Head Restraints

In past blog posts I have discussed various topics about whiplash from auto accidents in Baltimore. The last blog post mentioned how head restraint positioning can minimize injury risk if positioned properly prior to a rear-end motor vehicle collision.

Besides just properly positioning head restraints, certain automobile manufacturers have taken additional steps to make their vehicles more “crashworthy” so that occupants can “ride down” the crash and minimize any likelihood of injury. Notably, Saab created the “Saab anti-whiplash head restraint” or “SAHR”. It is a pretty interesting mechanism. When a car gets rear-ended the occupants mid back (torso) flattens out against the car seat, causing a cam to push the head restraint up and forward to “catch” the occupants neck, thereby instantly reducing the occupants likelihood of injury. It is a smart system- the head restraint is out of the way during normal driving and engages suddenly during impact.

Volvo has taken some steps to improve upon the design of car seats and head restraints as well. They created the WHIPS system. It is a bit more complex than the SAHR system. When impacted from the rear the WHIPS system translates rearward horizontally and then rotates rearward simultaneously, allowing an occupant to ride down the crash, thereby reducing injury risk.

Interestingly though these ideas have been proven to reduce injury risk to occupants we do not yet see these safety features in all passenger vehicles. You may be asking “why?”. Its all about money. Each of these designs ads money to the manufacturing of these vehicles and adds weight to the vehicles, thereby reducing fuel efficiency. As such, they are not often seen in most vehicles.

If you are fortunate enough to be driving one of these safer vehicles, congratulations! If not, let me leave you with this safe piece of advice as mentioned in a past blog post. Always adjust your headrest height vertically and minimize the space between your head restraint and the back of your head. If your vehicle comes equipped with a “pinch lock” on the head restraint, make sure it is engaged so that your head will not smash the head restraint down during impact.

Good luck and safe driving out there!

Head Restraint Height Can Impact Neck Injury Likelihood

When was the last time you checked that the height of your head restraint was appropriate to prevent whiplash? If you are like most people, the answer is probably never. Interestingly, it is this one step that, if performed by drivers even one time over the life of car ownership, would drastically reduce the incidence of whiplash in Baltimore and across the globe.

While change in velocities between two impacting vehicles play a part in relatively likelihood of injury following motor vehicle collision, as do human metrics (age, size, bracing for impact, previous injuries, etc), an often overlooked component about relatively likelihood of whiplash is something as simple as head restraint geometry.

The Insurance Institute for Highway Safety has created a static head restraint rating diagram. For proper safety, a head restraint should be positioned at least as high as the head’s center of gravity, which for most people is approximately 9 cm below the apex of the head. This vertical height is referred to as “topset” distance. The other component that they measure is called “backset.” Backset should be as little as possible, with a resting position of the back of the head no more than 8 cm from the head restraint.

For those who don’t want to measure their topset and backset- take one simple step. Move the headrest up as high and as far forward as possible (in vehicles that have adjustable head restraints). Doing so will decrease the likelihood of neck injury following a rear-end impact. This simple step may just save you months of therapy in my office!

If you, or anyone you know has suffered whiplash and is experiencing headaches, neck pain, or back pain associated with an auto accident in Baltimore or the surrounding areas, please contact Mid-Atlantic Spinal Rehab & Chiropractic or call us at (443) 842-5500. We would be happy to help!

Mild Traumatic Brain Injury in the News

Everywhere you look these days the top of concussions and/or mild traumatic brain injuries (MTBIs) is being discussed. The issue came to the national forefront over the summer when famed football player Junior Seau tragically took his own life. An autopsy revealed that Seau’s brain had signs of damage consistent with multiple concussions over his long playing career. Those who knew him well said that he was depressed, isolated, and generally just “not himself” prior to his death.

In addition to seeing signs of MTBI in football players and athletes, we are starting to see signs of MTBI and concussions in veterans. In yesterday’s 60 Minutes there was a news story entitled “Invisible Wounds of War” where the broadcasters looked into the “silent epidemic” of MTBI in our veterans. They determined that it was a severely underdiagnosed condition in our veterans. Just like how athletes are expected to rest and take time away following a concussion, so to are soldiers expected to take a break. Unfortunately they are not given the same opportunity to rest as professional athletes are often given. Concussions and PTSD are frequent conditions seen in our veterans returning from combat.

As a Baltimore Chiropractor that focuses on treating acutely injured clients with whiplash, concussions, mild traumatic brain injuries, along with headaches, neck pain, and back pain, I routinely see patients involved in auto accidents that results in concussions. In most cases the Emergency Room staff have not diagnosed these patients with these injuries. It is important to remember that ER staff are doing their job correctly in the majority of cases- they are ruling out life threatening conditions and releasing these patients when it is safe to do so. Chiropractors such as myself are some of the best resources to be able to diagnose and monitor concussions and MTBI since we see patients frequently following the onset of their symptoms. We are able to pick up on subtle differences day to day in behavior, emotion, cognition, and sleep differences that can be crucial in making an accurate diagnosis. Often the patients themselves do not realize that they are behaving differently and it is with the help of friends, family, and loved ones that help me make an accurate diagnosis.

The good news about concussions is that they are often self limiting and resolve in up to 12 weeks. Research has shown that repeat concussions, such as often seen in patients involved in multiple crashes in a short period of time, can lead to a worsening of symptoms, and in some cases, a problem that never completely resolves. At our office we routinely refer these patients to neurologists for appropriate diagnosis and testing. Don’t be afraid of your concussion- get the help you need!

Low Property Damage Crashes Can Cause Injury to Occupants 

One of my pet peeve’s in clinical practice is when claims adjustors arbitrarily decide not to pay the medical/chiropractic bills of their insureds involved in auto accidents in Baltimore. They like to make the claims that their bumpers “only had a scratch” and that as such, there is no way the occupants of the vehicle could be injured. I typically remark that I am not a mechanic- that is, I don’t care how much property damage a car has sustained…I don’t treat the car, I treat the occupants of the car. They sometimes go on to imply that any individual treating with less than $1,000 in property damage to their vehicle (so called M.I.S.T. “minor impact soft tissue” cases) must be committing fraud and/or embellishing on their complaints.

The idea that a vehicle’s property damage necessarily correlates with a patient’s injury likelihood/severity has not ever been found to exist scientifically. Yet despite this, everyone from claims adjustors to lay people to patients always seem to “know” that there is a relationship. In my nearly 5 years as a Chiropractor I have seen several hundred patients that have sustained injuries in an auto accident. These run the gamut from no/low property damage to complex roll overs with brain trauma where occupants had to be extricated by the jaws of life. I use my experience clinically and my post graduate education to examine and grade an individual’s injury. I do not pay much attention to property damage of a vehicle when assessing an individual’s complaints.

Dr. Arthur Croft in this month’s “Dynamic Chiropractic” wrote an article where he succinctly describes the paradox between occupant injury and property damage in an article entitled “Reimbursement for Treating Crash Victims: Deconstructing the Objections”. If you have about 5-10 minutes give it a read, it is really interesting.  It explains why it is possible to sustain significant injury even in cases of no/low property damage to a bumper. In the article he explains the paradox:

“A general understanding of collision mechanics goes a long way to explain this seeming paradox involving speed and injury. Without delving into too much depth here, the vehicle is relatively stiff in lower-speed ranges: it does not undergo crush or mechanical deformation here. Much of the kinetic energy of the collision is used to accelerate the vehicle and its occupant.

When the speed of the crash is high enough that the bumper energy absorber, bumper reinforcing bar, struts, or even frame elements are damaged, two things happen: (1) the kinetic energy used to deform these structures is no longer available to accelerate the vehicle; and (2) the duration of the collision is increased. And, since acceleration is equal to the change in velocity (delta V) divided by the time of the change in velocity (delta T), a relatively long collision pulse translates into less acceleration.”

I’ve said it before and I’ll say it again. If you have been involved in an auto accident in Baltimore City or Baltimore County and you are injured- get the care you need. A delay in care will only potentially lead to a chronic condition that will lead to the need for more care in the future.  Don’t let an insurance company dictate your care. You know your body. You know when you don’t feel right, and only you know what “normal” is for you.

At Mid-Atlantic Spinal Rehab & Chiropractic Dr. Gulitz, a Baltimore Chiropractor, routinely treats individuals involved in auto accidents with little to no property damage. Many times these clients do not have huge injuries that require a lot of care and that is great. But when they do require a lot of care and coordination with other providers, Dr. Gulitz is happy to help as well.

Regardless of property damage to your vehicle, if you are in pain from an auto accident in Baltimore, call Mid-Atlantic Spinal Rehab & Chiropractic at (443) 842-5500 or email us. We would be glad to help!