Subaru 2005 Legacy Owner's Manual page 109

Seat, seatbelt and SRS airbags
activated when the vehicle sustains a hard impact in
the undercarriage area from the road surface (such as
when the vehicle plunges into a deep ditch, is severely
bumped or knocked hard against an obstacle on the
road such as a curb).
1-78
" Examples of the types of accidents in which de-
ployment of the driver's/driver's and front pas-
senger's SRS frontal airbag(s) is unlikely to de-
ploy.
There are many types of collisions which might not