2023 TOYOTA PRIUS PRIME Owners Manual

3055-5. Using the driving support systems
5
Driving
active steering function) tim-
ing will also be changed.
When later is selected, the
emergency steering assist
(excluding the active steering
function) will not operate in most
cases.
 Vehicles with a driver monitor
camera: When the system
determines that the driver is
not facing forward, the pre-
collision warning and emer-
gency steering assist will
operate at the earlier timing,
regardless of the user setting.
 When the dynamic radar
cruise control is operating, the
pre-collision warning will
operate at the earlier timing,
regardless of the user setting.
 Vehicles with Traffic Jam
Assist: When the Traffic Jam
Assist is operating, the pre-
collision warning will operate
at the earlier timing, regard-
less of the user setting. 
When driving on a road with
clear lane lines with the
dynamic radar cruise control
operating, lane lines and pre-
ceding and surrounding vehi-
cles are detected using the
front camera and radar sen-
sor, and the steering wheel is
operated to maintain the vehi-
cle’s lane position.
Use this function only on highways
and expressways.
If the dynamic radar cruise control
is not operating, the function will not
operate.
In situations where the lane lines
are difficult to see or are not visible,
such as when in a traffic jam, sup-
port will be provi ded using the path
of preceding and surrounding vehi-
cles.
If the system determines that the
steering wheel has not been oper-
ated for a certain amount of time or
the steering wheel is not being
firmly gripped, the driver will be
alerted and this function will be
temporarily canceled.
If the steering wheel is firmly
gripped, the f unction will begin
operating again.
LTA (Lane Tracing
Assist)
LTA functions

3065-5. Using the driving support systems
When the function is operat-
ing, if the vehicle is likely to
depart from its lane, the driver
will be alerted via a display
and buzzer.
When the buzzer sounds, check
the area around the vehicle and
carefully operate the steering wheel
to move the vehicle back to the
center of the lane.
WARNING
■Before using the LTA system
●Do not overly rely on the LTA
system. The LTA system is not
a system which provides auto-
mated assistance in driving and
it is not a system which reduces
the amount of attention neces-
sary for safe driv ing. The driver
is solely responsible for paying
attention to their surroundings
and operating the steering
wheel as necessary to ensure
safety. Also, the driver is
responsible for taking adequate
breaks when fatigued, such as
when driving for a long time.
●Failure to perform appropriate
driving operations and pay care-
ful attention may lead to an
accident.
●When not using the LTA sys-
tem, turn it off using the LTA
switch.

3075-5. Using the driving support systems
5
Driving
■Operating conditions of func-
tion
This function is operable when all of
the following conditions are met:
●The LTA system detects lane lines
or the path of preceding or sur-
rounding vehicles.
●The dynamic radar cruise control
is operating.
●The lane width is approximately
10 to 13 ft. (3 to 4 m).
●The turn signal lever is not being
operated.
●The vehicle is not being driven
around a sharp curve.
●The vehicle is not accelerating or
decelerating more than a certain
amount.
●The steering wheel is not being
turned with a large force.
●The hands off steering wheel
warning ( P.307) is not operat-
ing.
●The vehicle is being driven in the
center of a lane.
■Temporary cancelation of func-
tions
●When the operating conditions are
no longer met, a function may be
temporarily canceled. However,
when the operation conditions are
met again, operation of the func-
tion will automatically be restored.
(  P.307)
●If the operating conditions of a
function are no longer met while
the function is operating, a buzzer
may sound to indicate that the
function has been temporarily
canceled.
●The steering assist operation of
the function can be overridden by
the steering wheel operation of
the driver.
■Lane departure warning func-
tion when the LTA is operating
●Even if the LDA warning method is
changed to vibration of the steer-
ing wheel, if the vehicle deviates
from the lane while the LTA is
operating, the warning buzzer will
sound to alert the driver.
●If steering wheel operation equiv-
alent to that necessary for a lane
change is detected, the system
will determine the vehicle is not
deviating from the lane and the
warning will not operate.
■Hands off steering wheel warn-
ing operation
●When the system determines the
driver is not holding the steering
wheel, a message urging the
driver to grip the steering wheel
and the icon show n in the illustra-
tion will be displayed on the multi-
information display to warn the
driver. If the system detects that
the steering wheel is held, the
warning will be canceled. When
using the system, make sure to
grip the steering wheel firmly,
regardless of whether the warn-
ing is operating or not.
●If no operations are detected for a
certain amount of time, the warn-
ing will operate an d the function
will be temporarily canceled. This
warning may also operate if the
driver only operates steering
wheel a small amount continu-
ously.
■Situations in which the hands
off steering wheel warning may
not operate properly
●Depending on the condition of the

3085-5. Using the driving support systems
vehicle, handle control condition
and road surface, the warning
function may not operate.
●Vehicles with LCA: In the following
situations, the system may not be
able to detect when the driver’s
hands are off the steering wheel.
• When a steering wheel cover is
installed
• When the driver is wearing gloves
• When foreign matter is attached to
the steering wheel
• When the driver is gripping the wood trim, seam of the leather,
spokes, or other pa rt of the steer-
ing wheel that does not have sen-
sors
●Vehicles with LCA: In the following
situations, the hands off steering
wheel warning may not operate
and the LTA function may con-
tinue operating even though the
driver’s hands are off the steering
wheel:
• When something other than a
hand is contacting the steering
wheel
• When a wide object or arms are
held across the steering wheel
The LTA will change between
ON/OFF each time the LTA
switch is pressed.
When the LTA is ON, the LTA indi-
cator will illuminate.
Enabling/disabling the
system
WARNING
■Situations in which the func-
tions may not operate prop-
erly
In the following situations, the
functions may not operate prop-
erly and the vehicle may depart
from its lane. Do not overly rely on
these functions. The driver is
solely responsible for paying
attention to their surroundings
and operating the steering wheel
as necessary to ensure safety.
●When a preceding or surround-
ing vehicle changes lanes (Your
vehicle may follow the preced-
ing or surrounding vehicle and
also change lanes)
●When a preceding or surround-
ing vehicle is swaying (Your
vehicle may sway accordingly
and depart from the lane)
●When a preceding or surround-
ing vehicle departs from a lane
(Your vehicle may follow the
preceding or surrounding vehi-
cle and also depart from the
lane)
●When a preceding or surround-
ing vehicle is being driven
extremely close to the left/right
lane line (Your vehicle may fol-
low the preceding or surround-
ing vehicle accordingly and
depart from the lane)

3095-5. Using the driving support systems
5
DrivingThe operating state of the LTA system is indicated.
WARNING
●When there are moving objects
or structures in the surrounding
area (Depending on the position
of the moving object or structure
relative to your vehicle, your
vehicle may sway)
●When the vehicle is struck by a
crosswind or the turbulence of
other nearby vehicles
●Situations in which the sensors
may not operate properly:
P.289
●Situations in which the lane may
not be detected: P.291
●When it is necessary to disable
the system: P.284
Operation display of steering wheel operation support
IndicatorLane displaySteering iconSituation
WhiteGray/WhiteGray
LTA is on standby
GreenGreenGreen
LTA is operating
Yellow
FlashingYellow
FlashingGreen
The vehicle is
departing the lane toward the side which the lane
display is flashing

3105-5. Using the driving support systems
*: If equipped
This function is linked to the LTA
and provides assistance in per-
forming lane changes through
steering wheel operations.
Use the this function only on high-
ways and expressways.
The steering assist operation can
be overridden by the steering wheel
operation of the driver.
The lane change assist function is
not designed to operate when
changing lanes at a junction.
■Operating conditions of func-
tion
This function is operable when all of
the following conditions are met:
●The LTA is operating.
●The lane change assist function is
enabled by a customize setting.
●The vehicle speed is between
approximately 55 and 85 mph (90
and 140 km/h).
●The system detects a broken
white line on the side which the
lane change is to be performed.
●A vehicle is not detected in the
lane toward which the turn signal
is operated.
●The steering wheel is not being
turned with a large force.
LCA (Lane Change
Assist)*
LCA functions
WARNING
■Before using the LCA system
●Do not overly rely on the LCA
system.
The LCA system is not a system
which provides automated assis-
tance in driving and it is not a sys-
tem which reduces the need for
checking an adjacent lane for
other vehicles, approaching vehi-
cles, etc. when changing lanes.
The driver is solely responsible for
paying attention to their surround-
ings and operating the steering
wheel as necessary to ensure
safety.
Also, do not use the LCA to
change lanes into which a lane
change should not be performed
(oncoming lanes, road shoulders,
etc.).
●Failure to perform appropriate
driving operations and pay care-
ful attention may lead to an
accident.

3115-5. Using the driving support systems
5
Driving
●The hands off steering wheel
warning (P.307) is not operat-
ing.
■Cancelation of functions
In the following situations, opera-
tion of the LCA may be canceled
with the display and buzzer:
●When the operating conditions
(  P.307) are no longer met
●When the system can no longer
detect lane lines
●When the turn signal lever is oper-
ated to the second position
( P.311)
●When the turn signal lever is oper-
ated in the opposite direction of
the lane change
●When the system detects opera-
tion of the steering wheel, brake
pedal or accelerator pedal by the
driver
If the system detects that a vehicle
is quickly approaching in the lane
toward which the turn signal is oper-
ated a buzzer will sound and a mes-
sage will be displayed to alert the
driver. At the same time the steering
wheel may be slightly operated to
help keep the vehicle away from the
approaching vehicle.
■Hands off steering wheel warn-
ing operation
When the system de termines the
driver is not holding the steering
wheel, a message urging the driver
to grip the steering wheel and the
icon shown in the illustration will be
displayed on the multi-information
display to warn the driver. If the sys-
tem detects that the steering wheel
is held, the warning will be can-
celed. When using the system,
make sure to grip the steering wheel
firmly, regardless of whether the
warning is operating or not.
■Situations in which the hands
off steering wheel warning may
not operate properly
●Depending on the condition of the
vehicle, handle control condition
and road surface, the warning
function may not operate.
●In the following situations, the sys-
tem may not be able to detect
when the driver’s hands are off
the steering wheel.
• When a steering wheel cover is installed
• When the driver is wearing gloves
• When foreign matter is attached to the steering wheel
• When the driver is gripping the wood trim, seam of the leather,
spokes, or other part of the steer-
ing wheel that does not have sen-
sors
●In the following situations, the
hands off steering wheel warning
may not operate and the LCA
function may continue operating
even though the driver’s hands
are off the steering wheel:
• When something other than a hand is contacting the steering
wheel
• When a wide object or arms are held across the steering wheel
If the turn signal lever is held in
the first position, the lane
change direction will be dis-
played and the function will
operate.
Operating the LCA

3125-5. Using the driving support systems
To change lanes by holding the
turn signal lever in the first posi-
tion without using the LCA, turn
the customize setting of the LCA
off.1
First position: LCA is opera-
tional
2 Second position: LCA is not
operational
LCA can be enabled/disabled
through a customize setting.
( P.626)
The operating state of the LCA system is indicated.
WARNING
■Situations in which the LCA
should not be used
●When driving on a one lane
road
●When there is no broken white
line between the current lane
and the lane to be changed to
Enabling/disabling the
system
Displays and system operation
LCA displaySteering iconCondition
Blue arrow and white lineGreen
LCA is operating
Grey
Approaching vehicle
detected while LCA is operating
Not displayed
Grey
Lane line no longer
detected while LCA is operating