2021 TOYOTA PRIUS Owners Manual (in English)

PRIUS_OM_OM47E09U_(U)
3054-5. Using the driving support systems
4
Driving
• If a vehicle ahead is narrow, such as a personal mobility vehi cle
• If a preceding vehicle has a small rear end, such as an unload ed truck
• If a vehicle ahead is carrying a load which protrudes past its rear bumper
• If a vehicle ahead is irregularly shaped, such as a tractor or side car
• If a vehicle ahead is a child sized bicycle, a bicycle that is carrying a large
load, a bicycle ridden by more than one person, or a uniquely shaped
bicycle (bicycle with a child seat, tandem bicycle, etc.)
• If a pedestrian/or the riding height of a bicyclist ahead is s horter than
approximately 3.2 ft. (1 m) or taller than approximately 6.5 ft. (2 m)
• If a pedestrian/bicyclist is wearing oversized clothing (a rai n coat, long
skirt, etc.), making their silhouette obscure
• If a pedestrian is bending forward or squatting or bicyclist i s bending for-
ward
• If a pedestrian/bicyclist is moving fast
• If a pedestrian is pushing a stroller, wheelchair, bicycle or other vehicle
• When driving in inclement weather such as heavy rain, fog, snow or a
sandstorm
• When driving through steam or smoke
• When the surrounding area is dim, such as at dawn or dusk, or while at
night or in a tunnel, making a detectable object appear to be n early the
same color as its surroundings
• When driving in a place where the surrounding brightness changes sud-
denly, such as at the entrance or exit of a tunnel
• After the hybrid system has started the vehicle has not been d riven for a
certain amount of time
• While making a left/right turn and for a few seconds after mak ing a left/
right turn
• While driving on a curve and for a few seconds after driving o n a curve
• If your vehicle is skidding • If a preceding vehicle has a low rear end, such as a low bed trailer
• If a vehicle ahead has extremely high ground clearance

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PRIUS_OM_OM47E09U_(U)
4-5. Using the driving support systems
• If the wheels are misaligned
• If a wiper blade is blocking the front camera
• The vehicle is being driven at extremely high speeds
• When driving on a hill
• If the radar sensor or front camera is misaligned
● In some situations such as the following, sufficient braking fo rce may not be
obtained, preventing the system from performing properly:
• If the braking functions cannot operate to their full extent, such as when
the brake parts are extremely cold, extremely hot, or wet
• If the vehicle is not properly maintained (brakes or tires are excessively
worn, improper tire inflation pressure, etc.)
• When the vehicle is being driven on a gravel road or other sli ppery sur-
face
■ If VSC is disabled
●If VSC is disabled ( P. 422), the pre-collision brake assist and pre-collision
braking functions are also disabled.
● The PCS warning light will turn on and “VSC Turned Off Pre-Coll ision Brake
System Unavailable” will be displayed on the multi-information display.
• If the front of the vehicle is raised or
lowered

307
PRIUS_OM_OM47E09U_(U)
4-5. Using the driving support systems
4
Driving
LTA (Lane Tracing Assist)
While driving on a road with clear white (yellow) lane lines, t he LTA
system warns the driver if the vehicle may deviate from the cur rent
lane or course
*, and also can slightly operate the steering wheel to
help avoid deviation from the lane or course
*. Also, while the dynamic
radar cruise control with full-s peed range is operating, this s ystem will
operate the steering wheel to ma intain the vehicle’s lane position.
The LTA system recognizes white
(yellow) lane lines or a course
*
using the front camera. Addition-
ally, it detects preceding vehicles
using the front camera and radar.
*: Boundary between asphalt and the side of the road, such as grass, soil,
or a curb
: If equipped
Summary of functions

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PRIUS_OM_OM47E09U_(U)
4-5. Using the driving support systems
WARNING
■Before using LTA system
● Do not rely solely upon the LTA system. The LTA system does not auto-
matically drive the vehicle or reduce the amount of attention that must be
paid to the area in front of the vehicle. The driver must always assume full
responsibility for driving safely by paying careful attention to the surround-
ing conditions and operating the steering wheel to correct the path of the
vehicle. Also, the driver must take adequate breaks when fatigu ed, such
as from driving for a long period of time.
● Failure to perform appropriate driving operations and pay caref ul attention
may lead to an accident, resulting in death or serious injury.
● When not using the LTA system, use the LTA switch to turn the system off.
■ Situations unsuitable for LTA system
In the following situations, use the LTA switch to turn the system off. Failure
to do so may lead to an accident, resulting in death or serious injury.
● Vehicle is driven on a road surface which is slippery due to rainy weather,
fallen snow, freezing, etc.
● Vehicle is driven on a snow-covered road.
● White (yellow) lines are difficult to see due to rain, snow, fo g, dust, etc.
● Vehicle is driven in a temporary lane or restricted lane due to construction
work.
● Vehicle is driven in a construction zone.
● A spare tire, tire chains, etc. are equipped.
● When the tires have been excessively worn, or when the tire inf lation pres-
sure is low.
● During emergency towing.
■ Preventing LTA system malfunctions and operations performed by
mistake
● Do not modify the headlights or place stickers, etc. on the sur face of the
lights.
● Do not modify the suspension etc. If the suspension etc. needs to be
replaced, contact your Toyota dealer.
● Do not install or place anything on the hood or grille. Also, d o not install a
grille guard (bull bars, kangaroo bar, etc.).
● If your windshield needs repairs, contact your Toyota dealer.

PRIUS_OM_OM47E09U_(U)
3094-5. Using the driving support systems
4
Driving
WARNING
■Conditions in which functions may not operate properly
In the following situations, the functions may not operate prop erly and the
vehicle may depart from its lane. Drive safely by always paying careful
attention to your surroundings and operate the steering wheel t o correct the
path of the vehicle without relying solely on the functions.
● When the follow-up cruising display is displayed ( P. 317) and the pre-
ceding vehicle is swaying. (Your vehicle may sway accordingly a nd depart
from the lane.)
● When the follow-up cruising display is displayed ( P. 317) and the pre-
ceding vehicle departs from its lane. (Your vehicle may follow the preced-
ing vehicle and depart from the lane.)
● When the follow-up cruising display is displayed ( P. 317) and the pre-
ceding vehicle is being driven extremely close to the left/righ t lane line.
(Your vehicle may follow the preceding vehicle and depart from the lane.)
● Vehicle is being driven around a sharp curve.
●When the follow-up cruising display is
displayed ( P. 317) and the preceding
vehicle changes lanes. (Your vehicle
may follow the preceding vehicle and
also change lanes.)
● Objects or patterns that could be mis-
taken for white (yellow) lines are pres-
ent on the side of the road (guardrails,
reflective poles, etc.).

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PRIUS_OM_OM47E09U_(U)
4-5. Using the driving support systems
WARNING
●There are shadows on the road that run parallel with, or cover, the white
(yellow) lines.
● The vehicle is driven in an area without white (yellow) lines, such as in
front of a tollgate or checkpoint, or at an intersection, etc.
● The white (yellow) lines are cracked, “Botts’ dots”, “Raised pa vement
marker” or stones are present.
● The white (yellow) lines cannot be seen or are difficult to see due to sand,
etc.
● The vehicle is driven on a road surface that is wet due to rain , puddles,
etc.
● The traffic lines are yellow (which may be more difficult to recognize than
lines that are white).
● The white (yellow) lines cross over a curb, etc.
● The vehicle is driven on a bright surface, such as concrete.
● If the edge of the road is not clear or straight.
● The vehicle is driven on a surface that is bright due to reflec ted light, etc.
●Vehicle is driven where the road
diverges, merges, etc.
● Repair marks of asphalt, white (yellow)
lines, etc. are present due to road
repair.

PRIUS_OM_OM47E09U_(U)
3114-5. Using the driving support systems
4
Driving
WARNING
●The vehicle is driven in an area where the brightness changes suddenly,
such as at the entrances and exits of tunnels, etc.
● Light from the headlights of an oncoming vehicle, the sun, etc. enters the
camera.
● The vehicle is driven on a slope.
● The vehicle is driven on a road which tilts left or right, or a winding road.
● The vehicle is driven on an unpaved or rough road.
● The traffic lane is excessively narrow or wide.
● The vehicle is extremely tilted due to carrying heavy luggage o r having
improper tire pressure.
● The distance to the preceding vehicle is extremely short.
● The vehicle is moving up and down a large amount due to road co nditions
during driving (poor r oads or road seams).
● When driving in a tunnel or at night with the headlights off or when a head-
light is dim due to its lens being dirty or it being misaligned .
● The vehicle is struck by a crosswind.
● The vehicle is affected by wind from a vehicle driven in a near by lane.
● The vehicle has just changed lanes or crossed an intersection.
● Tires which differ by structure, manufacturer, brand or tread p attern are
used.
● When tires of a size other than specified are installed.
● Snow tires, etc. are equipped.
● The vehicle is being driven at extremely high speeds.

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PRIUS_OM_OM47E09U_(U)
4-5. Using the driving support systems
■Lane departure alert function
When the system determines
that the vehicle might depart
from its lane or course
*, a
warning is displayed on the
multi-information display, and a
warning buzzer will sound to
alert the driver.
When the warning buzzer
sounds, check the area around
your vehicle and carefully oper-
ate the steering wheel to move
the vehicle back to the center of
the lane.
*: Boundary between asphalt and the side of the road, such as gra ss, soil, or
a curb
Functions included in LTA system