Lane Keeping Assist (LKA)

The Lane Departure Alert (LDA) system in the Lexus GS (L10) actively helps the driver prevent unintentional departure from the driving lane. The system combines visual warnings, steering wheel vibrations and, depending on the model, gentle steering interventions to correct the course. This section explains operation and provides tips for optimal use at night or in rain. Information on system limitations, such as poorly visible road markings, makes this section an important safety guide.

Summary of Functions

When driving on motorways or expressways with white or yellow lines, this function warns the driver if the vehicle may drift out of its lane and provides assistance by operating the steering wheel to keep the vehicle in its lane. In addition, the system also provides steering assistance when Dynamic Radar Cruise Control with Follow-up Distance Control is operating across the entire speed range, to keep the vehicle in its lane.

The LKA system detects visible white or yellow lines using the camera sensor located in the upper area of the windshield.

LKA System Functions

Lane Departure Warning Function

If the system determines that the vehicle may drift out of its lane, a warning is shown on the multi-information display and either the warning buzzer sounds to alert you or the steering wheel vibrates.

When the warning buzzer sounds or the steering wheel vibrates, check the traffic situation and carefully steer the vehicle back to the center between the white (yellow) lines.

Lane Change Monitoring Function

If the system determines that the vehicle may drift out of its lane, it provides assistance when needed by operating the steering wheel in small steps for a short time to keep the vehicle in its lane.

If the system detects that the steering wheel has not been operated for a set period of time, or that the steering wheel is not being held firmly, a warning is shown on the multi-information display and the function is temporarily deactivated.

Vehicle Swerving Warning

If the vehicle swerves, or if it appears that it may repeatedly drift out of its lane, the warning buzzer sounds and a message is shown on the multi-information display to alert the driver.

Lane Centering Assist

This function is linked to Radar Cruise Control and provides the necessary assistance by operating the steering wheel to keep the vehicle in its current driving lane.

If Radar Cruise Control is deactivated, Lane Centering Assist does not operate.

If the system detects that the steering wheel has not been operated for a set period of time, or that the steering wheel is not being held firmly, a warning is shown on the multi-information display and the function is temporarily deactivated.

WARNING

Before Using the LKA System

Do not rely solely on the LKA system. The LKA system does not steer the vehicle automatically, and it does not relieve the driver of the responsibility to pay attention to the area ahead of the vehicle. You alone are fully responsible for safe driving. You must always monitor the surrounding conditions and keep the vehicle in its lane with your steering inputs.

Also make sure to take regular breaks, for example on long trips when you notice signs of fatigue.

Improper driving and lack of attention may cause an accident resulting in death or serious injury.

How to Avoid Unintentional Operation of the LKA System

If you do not want to use the LKA system, turn it off with the LKA switch.

WARNING

Situations in Which the Lane Keeping Assist (LKA) Is Not Suitable

Do not use the LKA system in the following situations.

The system may not function properly, which may cause an accident resulting in death or serious injury.

• When a spare tire, snow chains, etc. are installed.
• When the tires are heavily worn or when tire pressure is low.
• When tires are used whose construction, manufacturer, brand or tread pattern are not identical.
• When there are objects or patterns at the roadside that could be mistaken for white (yellow) lines (guardrails, curbs and reflective posts).
• When driving on a road covered with snow.
• When the white (yellow) lines are difficult to see due to rain, snow, fog, dust, etc.
• When there are construction markings, white (yellow) lane markings, etc. on the asphalt due to road work.
• When driving on a temporary or narrowed lane in a construction area.
• When driving on a slippery road surface due to rain, snowfall, frost, etc.
• When driving on lanes of roads that are not motorways or expressways.
• When the vehicle is driven through a construction zone.
• When the vehicle is towing a trailer or towing another vehicle.

How to prevent malfunctions and unintended intervention of the LKA system

• Do not modify the headlights, and do not attach stickers, etc. to the lamp surfaces.
• Do not modify the suspension, etc. If the suspension, etc. needs to be replaced, contact a Lexus dealer or authorized repairer, or another qualified and properly equipped repair shop.
• Do not attach any objects to the hood or grille. Do not attach a front bumper guard (bull bar, etc.) either.
• If the windshield needs to be repaired, contact a Lexus dealer or authorized repairer, or another qualified and properly equipped repair shop.

Turning the LKA System On

Press the LKA switch to turn the LKA system on.

The LKA indicator light comes on and a message is shown on the multi-information display.

Press the LKA switch again to turn the LKA system off.

When the LKA system is turned on or off, the LKA system operation will resume in the same state the next time the engine is started.

Multi-Information Display Indications

1. 1
   LKA indicator light

   The indicator light status informs the driver of the operating status of the system.

   Lights white: The LKA system is operating.

   Lights green: The steering assist of the Lane Change Monitor function or the Lane Centering function is operating.

   Flashes orange: The Lane Change Warning function is operating.

2. 2
   Steering assist operation indicator.

   Indicates that the steering assist of the Lane Change Monitor function or the Lane Centering function is operating.

3. 3
   Lane Change Warning function indicator.

   Displayed when the multi-information display is switched to the driving support systems information screen.

The inside of the displayed white lines is white

Indicates that the system is detecting white (yellow) lines. If the vehicle deviates from the lane, the white line on the side the vehicle is deviating toward flashes orange.

The inside of the displayed white lines is black

Indicates that the system cannot detect white (yellow) lines or is temporarily deactivated.

Operating Conditions of Each Function

• Lane Departure Warning Function

This function is ready to operate when all of the following conditions are met.

The LKA system is on. The vehicle speed is at least approx. 50 km/h. The system detects white (yellow) lines. The driving lane is at least approx. 3 m wide. The turn signal lever is not operated. The vehicle is driving on a straight road or through a gentle curve with a radius of more than approx. 150 m. No system malfunctions are detected

• Lane Change Monitoring Function

This function is ready to operate when all of the following conditions are met in addition to the operating conditions for the Lane Change Warning function.

The "Steering Assist" setting under on the multi-information display is "On". The vehicle is not accelerated or decelerated by a certain amount or more. The steering wheel is not operated with the force required for a lane change. ABS, VSC, TRC, and PCS (Pre-Collision System) are not operating. The TRC or VSC system is not turned off. No warning is displayed that the hands are not on the steering wheel.

• Vehicle Swerving Warning

This function is ready to operate when all of the following conditions are met.

The "Sway Warning" setting under on the multi-information display is "On". The vehicle speed is at least approx. 50 km/h. The driving lane is at least approx. 3 m wide. No system malfunctions are detected.

• Lane Centering Assist

This function is ready to operate when all of the following conditions are met.

The LKA system is switched on. The setting for "Steering Assist" and "Lane Centering" under on the multi-information display is "On". The system detects white (yellow) lines. Dynamic Radar Cruise Control with Follow-up Distance Control is operating across the entire speed range. The driving lane is approx. 2.5 to 4.1 m wide. The turn signal lever is not operated. The vehicle is traveling on a straight road or through a gentle curve with a radius of more than approx. 200 m. No system malfunctions are detected. The vehicle is not accelerated or decelerated by a specific amount or more. The steering wheel is not operated with the force required for a lane change. ABS, VSC, TRC and PCS (Pre-Collision System) are not intervening. TRC or VSC is not turned off. The warning for hands off the steering wheel is not displayed. The lane change monitoring function is not operating.

Temporary Deactivation of Functions

If the operating conditions are no longer met, a function may be temporarily deactivated. However, once the operating conditions are met again, the function will automatically resume operation.

Lane Change Monitor Function/Lane Centering Function

Depending on the vehicle speed, the circumstances of the lane departure, the road surface condition, etc., the operation of the functions may not be detected or the functions may not operate.

Lane Departure Warning Function

The warning buzzer may be difficult to hear due to outside noise, audio playback, etc. In addition, the steering wheel vibrations may be difficult to feel depending on road surface conditions, etc.

Warning when hands are not on the steering wheel

When the system detects that the driver's hands are not on the steering wheel while the Lane Change Monitor function or the Lane Centering function is activated, a warning message is shown on the multi-information display.

If the driver does not grip the steering wheel in response, the warning buzzer sounds, a warning message is shown, and the function is temporarily deactivated. The same warning is given if the steering wheel is only loosely held while driving. However, depending on road surface conditions, etc., the function may not be deactivated.

White (yellow) lines are present on only one side of the road

The LKA system does not respond on the side where no white (yellow) lines are detected.

Conditions in Which the Functions May Not Operate Properly

In the following situations, the camera sensor may not detect white (yellow) lines, and various functions may not operate properly.

• Shadows on the road run parallel to the white (yellow) lines or obscure them.
• The vehicle is driving in an area without white (yellow) lines, such as before a toll station or checkpoint, or at an intersection, etc.
• The white (yellow) lines are interrupted, or there are road stud markers or stones present.
• The white (yellow) lines are difficult or impossible to see due to sand, etc.
• The vehicle is driving on a road surface that is wet due to rain, puddles of water, etc.
• The lane markings are yellow (and may therefore be harder to detect than white lines).
• The white (yellow) lines run over a curb, etc.
• The vehicle is driving on a light-colored road surface, e.g. concrete.
• The vehicle is driving on a road surface that appears bright due to reflected light, etc.
• The vehicle is driving in an area where the brightness changes abruptly, such as at a tunnel entrance or exit, etc.
• Light from the headlights of an oncoming vehicle, the sun, etc. shines directly onto the camera.
• The vehicle is driving through a junction, merging lane, etc.
• The vehicle is driving on a slope.
• The vehicle is driving on a road that slopes to the left or right, or on a winding road.
• The vehicle is driving on an unpaved or poor-quality road.
• The vehicle is driving through a sharp bend.
• The driving lane is extremely narrow or wide.
• The vehicle leans significantly due to a heavy cargo load or incorrect tire pressure.
• The distance to the vehicle ahead is extremely short.
• The vehicle moves up and down while driving due to road conditions (poor roads or coarse asphalt joints).
• The headlight lenses are dirty and provide weak illumination at night, or the headlight aiming is out of adjustment.
• The vehicle is affected by crosswind.
• The vehicle has just changed lanes or crossed an intersection.
• Winter tires, etc. are installed.

Warning message

Warning messages indicate a system malfunction or advise the driver that special caution is required while driving.

Customization

You can change the following settings.

For how to change the settings, refer to.

The Lane Departure Alert with Steering Assist (LDA) in the Lexus GS GRL1 2016–2020 helps keep the vehicle in its lane and warns when the vehicle unintentionally leaves the lane. The system actively supports the driver and enhances safety, especially on motorways and expressways.

Thanks to precise camera technology, the Lexus GS 4th generation reliably detects lane markings and adjusts steering assistance to the driving situation. This makes the sports sedan a benchmark in driver assistance.