Upon arrival, initial responders should be sent towards the wreckage and perform an Inner Circle Survey of the incident. This is a total 360-degree walk around the incident, looking towards the wreckage, to help obtain some vital information about the incident. Take note of issues like the number of victims, doors locked or jammed, vehicles still running, leaking fluids or fuels, involved utilities (electric/gas), and potential victim access. Be sure to take the time to “Read the Wreckage” for impact-related injuries. Reading the wreckage takes into consideration the kinetic energy (the force of energy in motion) that led to the potential traumatic injuries caused as energy is transferred through the vehicle (see Photo 5). The sudden stop from the accident will transform this energy into damage to the vehicles. Those forces are also transmitted through the occupants as well, and can be compounded by vehicles that are moving in opposite directions (head-on impact). Consider the magnitude of the impact at the scene: first, the vehicle collides with an object, and then the victim collides with the vehicle. Finally, the victim’s internal organs collide with one another. The final collision is the one that can do the most damage to the victim. Identifying these impact signatures will help identify potential mechanisms of injury that crews can expect to encounter in victims on-scene.
For example, frontal collisions result in more fatalities than any other point of impact. During frontal collisions, both vehicles are moving at approximately the same speed, meaning that they possess similar kinetic energy. At the moment they undergo a collision, their energy is added together. So, if both vehicles were traveling at 35 miles per hour, their force of impact would be similar to hitting a stationary object at 70 miles per hour. Rear-end collisions can contribute to injury and stresses to the neck, back, and spine. Side-impact collisions can result in serious head and neck injuries, considering these are small spaces with thin crumple zones, and limited protection, at best. Rollovers result in many ejection fatalities, with unrestrained victims being thrown through openings from broken glass.
Additionally, identifying the type of vehicle involved in the extrication will help identify types of methods that will be used during operations, based on strong points of the vehicles for stabilization and disentanglement. Vehicles will range in size, horsepower rating, amenities, safety features, and construction techniques. Three of these construction types include Full Frame, Unibody, and Space Frame vehicles.
Full Frame vehicles incorporate frame rails that run from the front of the vehicle, underneath the passenger compartment, to the rear of the vehicle. These rails provide mounting support for passenger compartments, powertrains, and other vehicular components.
Unibody vehicles have short frame rails that terminate underneath the vehicle, at the front of the passenger compartment or firewall area. This type of construction utilizes the passenger compartment for integrity and stability.
Space Frame utilizes a steel cage-like structure that carries the vehicle’s loads and stresses, and holds the vehicle together.
These types of construction will be found in all types of vehicles, ranging from subcompacts, compacts, full size, sport-utility vehicles, limousines, pick-up trucks, and minivans. The best way to tell on-scene is to look underneath the vehicle to check for frame rails, and to see where they terminate. If there are no full-length frame rails, then expect Unibody or Space Frame construction.
New car technology has made some significant strides in the last decade, but some have led to problematic issues on the rescue scene:
- Reinforced wheel and engine deflection systems allow the wheels and engine components to deflect under the vehicle and away from the passengers.
- Crumple zones in engine compartments have been designed to absorb more energy.
- Impact bars constructed of boron or micro-alloy steel can add to problems when crews are trying to remove or open the door of a vehicle.
- Air bags and seat belt pre-tensioners can now be found almost anywhere inside the vehicle (see Photos 6 and 7). These mechanisms have been the cause of many rescuer injuries.
- New technology of glass is designed to keep the unrestrained passenger inside the vehicle during impact; it can also make gaining access for rescuers much more difficult.
- Batteries are now located anywhere throughout the vehicle, creating an energizing issue for much of the wreckage.
- Front and rear bumpers can become “loaded” after impact, resulting in the bumper assembly becoming a projectile during the extrication.
- Various fuel types, including hybrid-powered vehicles, can add high voltage and explosive concerns to the operation.
The key to success with these advancements is to identify them early on in the operation, so adequate safety precautions can be taken. There are many case histories of rescuers being hurt and severely injured due to some of these “safety” devices.