Lexus 2003 LS Owner's Manual page 155

However, this threshold velocity will be considerably higher if
the vehicle strikes an object, such as a parked vehicle or sign
pole, which can move or deform on impact, or if the vehicle is
involved in an underride collision (e.g. a collision in which the
front of the vehicle "underrides", or goes under, the bed of a
truck, etc.).
It is possible that in some collisions where the forward
deceleration of the vehicle is very close to the designed
threshold level, the SRS airbags and the seat belt
pretensioners may not activate together.
For the safety of all occupants, always wear your seat belts
properly.
COMFORT ADJUSTMENT
16L615

1 Collision from the side
2 Collision from the rear
3 Vehicle rollover
The front airbags are generally not designed to inflate if
the vehicle is involved in a side or rear collision, if it rolls
over, or if it is involved in a low–speed frontal collision.
But, whenever a collision of any type causes sufficient
forward deceleration of the vehicle, deployment of the
front airbags may occur.
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