Toyota 2015 Prius Owner's Manual page 268

2-2. Instrument cluster
Head-up display
The head-up display can be used to project vehicle speed and other
information onto the windshield.
246
PRIUS_OM_OM47A17U_DVD_(U)
Head-up display
Display brightness will change
automatically according to the
brightness of the surrounding
area.
HUD (Head-up display)
main switch
Turn-by-turn navigation
switch (if equipped)
Display position adjustment
switch
Display brightness adjust-
ment switch
Used to adjust the display
brightness to the desired level.
: If equipped