Page 203 of 600

2034-5. Using the driving support systems
4
Driving
IS350/300/200t_U (OM53D18U)
This mode employs a radar sensor to detect the presence of vehicles up to
approximately 400 ft. (120 m) ahead, determines the current vehicle-to-vehicle
following distance, and operates to maintain a suitable following distance from
the vehicle ahead.
Note that vehicle-to-vehicle distance will close in when traveling on long downhill
slopes.
Example of constant speed cruising
When there are no vehicles ahead
The vehicle travels at the speed set by the driver. The desired vehicle-to-vehicle dis-
tance can also be set by operating the vehicle-to-vehicle distance control.
Example of deceleration cruising
When the vehicle ahead is driving slower than the set speed
When a vehicle is detected running ahead of you, the system automatically deceler-
ates your vehicle. When a greater reduction in vehicle speed is necessary, the system
applies the brakes. A warning tone warns yo u when the system cannot decelerate suf-
ficiently to prevent your vehicle from closing in on the vehicle ahead.
Example of follow-up cruising
When following a vehicle driving slower than the set speed
The system continues follow-up cruising wh ile adjusting for changes in the speed of
the vehicle ahead in order to maintain the vehicle-to-vehicle distance set by the driver.
Example of acceleration
When there are no longer any vehicles ahead driving slower than the set
speed
The system accelerates until the set speed is reached. The system then returns to con-
stant speed cruising.
Driving in vehicle-to-vehicle distance control mode
1
2
3
4
Page 209 of 600

2094-5. Using the driving support systems
4
Driving
IS350/300/200t_U (OM53D18U)
■Dynamic radar cruise control can be set when
●The shift lever is in D.
●Range 4 or higher of D has been selected by using the paddle shift switch.
●Vehicle speed is above approximately 30 mph (50 km/h).
■Accelerating after setting the vehicle speed
The vehicle can accelerate by operating the accelerator pedal. After accelerating, the
set speed resumes. However, during vehicle-to-vehicle distance control mode, the vehi-
cle speed may decrease below the set speed in order to maintain the distance to the pre-
ceding vehicle.
■Automatic cancelation of vehicle- to-vehicle distance control mode
Vehicle-to-vehicle distance control driving is automatically canceled in the following situ-
ations:
●Actual vehicle speed falls below approximately 25 mph (40 km/h).
●VSC is activated.
●TRAC is activated for a period of time.
●When the VSC or TRAC system is turned off by pressing the VSC OFF switch.
●The sensor cannot detect correctly because it is covered in some way.
●The windshield wipers are operating at high speed (when the wipers are in AUTO
mode or the high speed wiper operation).
●When snow mode is set.
●Pre-collision braking is activated.
If vehicle-to-vehicle distance control mode is automatically canceled for any other rea-
son, there may be a malfunction in the system. Contact your Lexus dealer.
■Automatic cancelation of constant speed control mode
The cruise control will stop maintaining the vehicle speed in the following situations:
●Actual vehicle speed is more than approximately 10 mph (16 km/h) below the set vehi-
cle speed.
●Actual vehicle speed falls below approximately 25 mph (40 km/h).
●VSC is activated.
●TRAC is activated for a period of time.
●When the VSC or TRAC system is turned off by pressing the VSC OFF switch.
●Pre-collision braking is activated.
Page 210 of 600
2104-5. Using the driving support systems
IS350/300/200t_U (OM53D18U)
■Radar sensor and grille cover
Always keep the sensor and grille cover clean to ensure that the vehicle-to-vehicle dis-
tance control mode operates properly. (Some obstructions, such as snow, ice and plastic
objects, cannot be detected by the obstruction sensor.)
Dynamic radar cruise control is cancel ed if an obstruction is detected.
■Operation guide display
When the dynamic radar cruise control switch is operated, a guidance display is shown
on the meters for a few seconds as to how to operate the dynamic radar cruise control
switch or distance switch. ( P. 8 9 )
■Warning messages and buzzers for dynamic radar cruise control
Warning messages and buzzers are used to indicate a system malfunction or to inform
the driver of the need fo r caution while driving. (P. 4 8 6 )
Grille cover
Radar sensor
1
2
Page 213 of 600
2134-5. Using the driving support systems
4
Driving
IS350/300/200t_U (OM53D18U)
CAUTION
■Situations unsuitable for dynamic radar cruise control
Do not use dynamic radar cruise control in any of the following situations.
Doing so may result in inappropriate speed control and could cause an accident result-
ing in death or serious injury.
●Roads where there are pedestrians, cyclers, etc.
●In heavy traffic
●On roads with sharp bends
●On winding roads
●On slippery roads, such as thos e covered with rain, ice or snow
●On steep downhills, or where there are sudden changes between sharp up and down
gradients
Vehicle speed may exceed the set speed when driving down a steep hill.
●At entrances to freeways and highways
●When weather conditions are bad enough that they may prevent the sensors from
detecting correctly (fog, snow, sandstorm, heavy rain, etc.)
●When an approach warning buzzer is heard often
●During emergency towing
Page 214 of 600
2144-5. Using the driving support systems
IS350/300/200t_U (OM53D18U)
CAUTION
■When the sensor may not be correctly detecting the vehicle ahead
In the case of the following and depending on the conditions, operate the brake pedal
when deceleration of the system is insuff icient or operate the accelerator pedal when
acceleration is required.
As the sensor may not be able to correctly detect these types of vehicles, the approach
warning ( P. 207) will not be activated, which may lead to an accident resulting in
death or serious injury.
●Vehicles with small rear ends (traile rs with no load on board, etc.)
●Vehicles that cut in suddenly
●Vehicles traveling at low speeds
●Vehicles that are not moving in the same lane
●Motorcycles traveling in the same lane
Page 215 of 600
2154-5. Using the driving support systems
4
Driving
IS350/300/200t_U (OM53D18U)
CAUTION
■Conditions under which the vehicle-to-vehicle distance control mode may not func-
tion correctly
Operate the brake pedal (or accelerator pe dal operation depending on the situation)
as necessary in the following conditions as the radar sensor may not be able to cor-
rectly detect vehicles ahead, which may lead to an accident resulting in death or seri-
ous injury.
●When water or snow thrown up by the surrounding vehicles hinders the detecting of
the sensor
●When your vehicle is pointing upwards
(caused by a heavy load in the trunk, etc.)
●When the road curves or when the lanes are
narrow
●When steering wheel operation or your posi-
tion in the lane is unstable
●When the vehicle ahead of you decelerates
suddenly
Accelerate Accelerate Decelerate
Page 216 of 600
2164-5. Using the driving support systems
IS350/300/200t_U (OM53D18U)
CAUTION
■Handling the radar sensor
Observe the following to ensure the cruise control system can function effectively.
Otherwise, the system may not detect correctly and could result in an accident.
●Keep the sensor and grille cover clean at all times.
Clean the sensor and grille cover with a soft cloth so you do not mark or damage
them.
●Do not subject the sensor or surr ounding area to a strong impact.
If the sensor moves even slightly off posi tion, the system may not work normally or
malfunction. If the sensor or surrounding area is subject to a strong impact, always
have the area inspected and adjusted by your Lexus dealer.
●Do not disassemble the sensor.
●Do not attach accessories or stickers to the sensor, grille cover or surrounding area.
●Do not modify or paint the sensor and grille cover.
●If the radar sensor needs to be replaced, contact your Lexus dealer.
Page 217 of 600
2174-5. Using the driving support systems
4
Driving
IS350/300/200t_U (OM53D18U)
While driving on a road that has lane markers, this system recognizes the lane
markers using a camera as a sensor to alert the driver when the vehicle deviates
from its lane.
If the system judges that the vehicle has deviated from its lane, it alerts the driver
using a buzzer and indications on the multi-information display.
Camera sensor
LDA (Lane Departure Alert)
: If equipped
Summary of function