LDA (Lane Departure Alert with Steering Assist)
Road Sign Assist (RSA) in the Lexus GS (4th generation) provides better orientation and greater safety in road traffic. The system reads relevant road signs such as speed limits and no-passing zones and shows them clearly on the multi-information display. This section provides practical information on the function, limitations in adverse weather conditions and care of the camera sensor. This makes RSA a valuable everyday aid.
Summary of Functions

When driving on motorways or expressways with white (yellow) lines, this function warns the driver if the vehicle may leave its lane and provides assistance by operating the steering wheel to keep the vehicle in its lane.
The LDA system detects visible white (yellow) lines using the camera sensor located in the upper area of the windshield.
LDA System Functions

Lane Departure Warning Function
If the system determines that the vehicle may leave its lane, a warning is displayed on the multi-information display, and either the warning buzzer sounds to alert you or the steering wheel vibrates*.
If 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.
*: If equipped

Steering Control 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.
Except for Israel: If the system determines 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 displayed on the multi-information display and the function is temporarily deactivated.
For Israel: If the system determines 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 displayed on the multi-information display and the warning buzzer sounds.

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.
WARNING
Before Using the LDA System
Do not rely solely on the LDA system. The LDA system neither steers the vehicle automatically nor relieves the driver of the responsibility to watch 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 prevent unintentional LDA system operation
If you do not want to use the LDA system, turn it off with the LDA switch.
Situations for which the Lane Departure Alert (LDA) is not suitable
Do not use the LDA 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.
WARNING
How to prevent malfunctions and unintentional LDA system operation
- 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 LDA system on
Press the LDA switch to turn the LDA system on.
The LDA indicator light comes on and a message is displayed on the multi-information display.
Press the LDA switch again to turn the LDA system off.
When the LDA system is turned on or off, its operating state is retained the next time the engine is started.
GS350/GS200t

GS F

Multi-Information Display Indications

- LDA indicator light.
The indicator light status informs the driver of the operating status of the system.
Lights white: The LDA system is operating.
Lights green: The steering assist of the steering control function is operating.
Flashes orange: The Lane Change Warning function is operating.
- Steering assist operation indicator.
Indicates that the steering assist of the steering control function is operating.
- 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 LDA system is switched 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.- Steering Control 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 set to "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 activated. The TRC or VSC system is not turned off. Except for Israel: No warning is displayed indicating 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.■ Temporary deactivation of the 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.
■ Steering control 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 change 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 due to road conditions, etc. (if equipped).
■ Warning when hands are not on the steering wheel
Except for Israel: When the steering control function is enabled and the system detects that the driver's hands are not on the steering wheel, a warning message is displayed 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.
For Israel: When the lane change monitoring function or lane tracing assist is enabled and the system detects that the driver's hands are not on the steering wheel, a warning message is displayed on the multi-information display and the warning buzzer sounds.
■ White (yellow) lines are present on only one side of the road
The LDA system does not respond on the side where no white (yellow) lines are detected.
■ Conditions under 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.
■ Personal settings
You can change the following settings.

*: If equipped
For how to change the settings, refer to.
The LDA system in the Lexus GS GRL1 combines lane departure warning and steering assist in one advanced safety package. It detects road markings and helps keep the vehicle safely within its lane. Warnings are given visually, audibly, or through steering wheel vibrations.
The combination of comfort and safety makes the Lexus GS 2016–2020 an ideal choice for long journeys and demanding routes.
FAQWhen is the steering assist active?
When the system detects that the vehicle is about to leave its lane and the conditions for intervention are met.
Can the LDA system be turned off?
Yes, the system can be turned on and off with the LDA switch.
Test yourself
A quick Lexus GS quiz: every answer comes with an explanation and a link to the manual page.