Fiat Abarth 500 2015 Owner's Manual page 63

5. Can the child stay seated like this for the whole trip?
If the answer to any of these questions was "no," then the
child still needs to use a booster seat in this vehicle. If the
child is using the lap/shoulder belt, check seat belt fit
periodically and make sure the seat belt buckle is latched.
A child's squirming or slouching can move the belt out of
position. If the shoulder belt contacts the face or neck,
move the child closer to the center of the vehicle, or use
a booster seat to position the seat belt on the child
correctly.
THINGS TO KNOW BEFORE STARTING YOUR VEHICLE 61
WARNING!
Never allow a child to put the shoulder belt under an
arm or behind their back. In a crash, the shoulder belt
will not protect a child properly, which may result in
serious injury or death. A child must always wear
both the lap and shoulder portions of the seat belt
correctly.
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