Lexus ES-300 2001 Manual page 172

COMFORT ADJUSTMENT
" SRS side airbags
In response to a severe side impact, the SRS side
airbags work together with the seat belts to help
reduce injury by inflating. The SRS side airbags help
to reduce injuries mainly to the driver's or front
passenger's chest.
The SRS side airbag on the passenger seat is activated
even with no passenger in the front seat.
Be sure to wear your seat belt properly.
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