Effect of Driving Without The Seat Belt

It is a good driving habit of utmost importance to fasten the seat belt and shoulder harness.

If a car should collide with any exterior object, a second collision occurs inside the car between the vehicle and its occupants.  It is this second collision that does the damage.
To illustrate the principle of second collision:  when you walk into a door in the dark, the probability is that you bump your head or get a black eye, yet it’s only at walking speed ─ a mere two to three miles per hour.  Even at the lowest speed,  a sudden, violent stop can be both painful and dangerous, more so if the impact is felt due to sudden collision at the speed of 20 or 30 or 60 miles per hour.
By law, all American cars today are equipped with a safety harness, but  many people do not use it and take it for granted.   Research prove that such restraints reduce the possibility of serious injury in an accident by 35 to 50%.  Minor collisions can occur anywhere, anytime, even on your own street, not just in the fast highways.
An expert driver systematically buckles his belt not only for safety but also an aid to comfortable driving.  With belt fastened, he does not sway from side to side on turns or lunge fore and aft in starts and stops.  His body remains firmly anchored at all times, maintaining the correct posture so important to control.  The lessened effect of road bumps and vibrations eliminates a major cause of fatigue on long trips.
Just like adjusting the seat and the mirrors, fastening the seat belt while the engine warms up is no hardship, anyway, so do it without fail.