GMC 2003 Safari Owner's Manual page 50

People should never hold a baby in their arms
while riding in a vehicle. A baby doesn't weigh
much
-
until a crash. During a crash a baby
will become so heavy
it
is not possible to
hold
it.
For example, in a crash at only
25 mph (40 km/h), a 12-lb. (5.5 kg) baby will
suddenly become a 240-lb. (1 10 kg) force on
a person's arms.
1-43