Subaru 2003 Impreza - Manual (Page 293)

IMPREZA(NA) A1850BE-A (ENGLISH)
In case of emergency
9-2
If you park your vehicle in case of an
emergency
The hazard warning flasher should be used in day
or night to warn other drivers when you have to park
your vehicle under emergency conditions.
Avoid stopping on the road. It is best to safely pull
off the road if a problem occurs.
The hazard warning flasher can be activated
regardless of the ignition switch position.
Turn on the hazard warning by pushing the hazard
warning flasher switch. Turn it off by pushing the
switch again.
NOTE
When the hazard warning flasher is on, the turn
signals do not work.