The emergency flashers are used to warn other drivers when the vehicle has to be stopped in the road due to a breakdown, etc.
Press the switch.
All the turn signal lights will flash.
To turn them off, press the switch once again.

Emergency flashers
If the emergency flashers are used for a long time while the engine is not operating, the battery may discharge.
If your vehicle has to be
stopped in an
emergencyTrailer towing tips
Your vehicle will handle differently when towing a trailer. Help to avoid
an accident, death or serious injury, keep the following in mind when
towing:
speed limits for towing a trailer vary by state or province. Do
not
exceed the posted towing speed limit.
Toyota recommends ...