accelerations and in each of the three tests occupant accelerations
were greater than vehicle accelerations.
A pattern in the disparity between the head and the chest
emerged in the graphs. With a speed change of 1.25 km/h
(0.78 mph) the accelerations of the head and chest are similar in
both magnitude and form. The head and chest moved in synchrony
to within 0.04g.
When the speed change was increased to 2.26 km/h (1.4 mph)
the head and chest accelerations were still similar in both magnitude
and form. The head and chest moved in synchrony to within
0.29g.
When the speed change was increased to 5.69 km/h (3.54 mph) a
difference between the acceleration of the head and chest became
evident. The accelerations of the head and chest were no longer
similar in magnitude; those of the head exceeded those of the chest
by up to 2.18g.