Wheelchair Accessible Vehicle Restraint Issues
Fearful that you may think you have inadvertently landed on a science and technology website, let’s have a recap of Newton’s Laws of Motion. Most people have probably heard of them, but only a scholastic few can probably quote them all. Fewer still may understand their significance in day to day life and in particular the implications to a wheelchair passenger travelling in a Wheelchair Accessible Vehicle
- First law: The velocity of a body remains constant unless the body is acted upon by an external force.
- Second law: The acceleration ‘a’ of a body is parallel and directly proportional to the net force ‘F’ and inversely proportional to the mass ‘m’ or F = ma.
- Third law: The mutual forces of action and reaction between two bodies are equal, opposite and collinear.
In day to day life this equates to two basic facts:
- If something is moving and an attempt is made to suddenly stop it, it will want to carry on moving
- The heavier the object, the greater the forces involved and under acceleration, objects become heavier
Everyone has heard of fighter pilots and astronauts experiencing the affects of high g manoeuvres. In the case of pilots, their bodies are constantly undergoing the stresses and strains of acceleration throughout the flight envelope. It’s particularly noticeable during turning manoeuvres where in layman’s terms, the centrifugal force in the turn leads to the pilot’s body increasing in weight.
Bizarrely, one does not have to take to the skies to experience the same phenomenon on solid ground, and that is something not everyone appreciates. The circumstances I have in mind initially, is none other than everyday driving. Whereas the forces involved when accelerating, decelerating and turning may not be quite up to a Typhoon ‘fast jet’, they are nevertheless significant. As a consequence, unless the wheelchair is adequately secured within a Wheelchair Accessible Vehicle, there is going to be movement of the chair, which if nothing else is going to result in an uncomfortable ride for its passenger.
But without doubt, the greatest significance of what I have written comes into play should the vehicle have the misfortune of being involved in an impact related accident; something one hopes will never happen, but with the complexities of modern driving, can never be ruled out.
Here the forces and other figures involved are several orders of magnitude greater than even those experienced by the previously mentioned fighter pilot. A collision will result in a change of direction of the motion of the vehicle and in the case of a head-on crash, an extremely rapid deceleration. I do not intend to dwell on the outcome; hopefully, from what I have written earlier it can be seen that unless the wheelchair is adequately restrained within the vehicle, the consequences will be extremely dire.