ADAS Features: Lane Keeping Assist System (LKAS)

Lane veering is a serious issue as thousands of accidents each year in the United States are caused by lane changing or lane departure. Fortunately, engineers have rushed to fix this issue, and Lane Keeping Assist Systems (LKAS) have drastically reduced these crashes.

This blog gives a quick rundown of what LKA systems are, how they function, how they are integrated, and common calibration considerations. \

What is a Lane Keeping Assist System (LKAS) and how does it work?

A Lane Keeping Assist System (LKAS) is an ADAS feature designed to keep the vehicle in its lane. Using front mounted sensors on the windshield or the rear-view mirror, this system can identify lane-markings and determine if the vehicle is unintentionally veering into another lane or off of the road. 

LKAS is engineered to identify the difference between intentional and unintentional lane departure. Typically, LKAS is triggered if a vehicle leaves a lane without use of a turn signal. 

When the system detects an unintentional lane departure, it has the power to gently steer the car back into the center of the lane without user input. Under some manufacturer-specific circumstances, LKAS may also apply the brakes to aid in the recentering guidance maneuver. Typically, LKAS will also alert the driver via visual and audio alerts.

LKAS is specifically designed for highway driving, relying on clear lane markings to function properly. These systems typically only function at speeds of at least 40 mph, and are highly effective at maintaining lane integrity. It’s important to note that this system still requires full attention to the road by the driver, it is not a fully autonomous system. Malfunctions can still happen due to missed or improper calibrations, poor road conditions, or hilly and curved roads, so that text from your ex can wait (or probably better ignored completely). 

Let’s look at how LKAS can vary according to manufacturer and other factors.

Key differences in LKAS among manufacturers

Honda Lane Keeping Assist System

With Honda’s LKAS, you must manually activate it with a button on the steering wheel. The camera sensors are located in the review mirror, and there is progressively stronger steering correction based on how close the vehicle gets to leaving its lane. There are also pre-departure signals to the driver such as vibrations of the steering wheel and a visual warning on the instrument panel

Ford Lane-Keeping System

Ford’s Lane-keeping system has the ability to choose between system warnings and assistance. This system is also powered by a front-facing camera sensor that identifies the lane markings. There are three modes for this LKAS, which is turned on or off with a button on the left side stalk. The driver can choose for Aid and Alert, where the vehicle both alerts that driver and steers the vehicle back to the center, Aid where the vehicle only steers without warning, or Alert where the vehicle warns the driver but doesn’t intervene.

Volkswagen Lane Assist

Volkswagen’s Lane Assist works at speeds higher than 35 mph, and warns the driver with auditory alerts, and can also control steering if necessary. This feature is also powered by a forward-facing camera.

Toyota Lane Departure Alert with Steering Assist

Toyota also integrates its LKAS with Land Departure Warning (LDW) and also with Adaptive Cruise Control (ACC). This LKAS begins functioning at 30 mph and is considered an extension of its LDW, it can also gently steer the car back into the lane. With ACC, the same sensors and systems are used to keep the car centered while in ACC.

While there are many more examples, this highlights that these four large manufacturers have some small but important variation in their LKA systems. It is vital your shop treats each vehicle as unique because every system requires unique care.

How LKAS integrates with other ADAS features

Common among ADAS features is the high level of integration they share with other counterparts. LKAS is no exception to this rule. LKAS shares sensors, information, and functions with many ADAS features, but the most important two to note in terms of critical function are Lane Departure Warning (LDW) and Adaptive Cruise Control (ACC).

Lane Departure Warning (LDW)

LDW systems are very similar to LKAS in their function and purpose, yet there are some differences. This similarity, being the goal to avoid lane veering, allows for very high integration between the two features. This high level of integration between the two is why some argue that LKAS is just a more high-tech version of LDW.

LDW and LKAS use the same front-mounted sensors to function, such as cameras, infrared or LiDAR sensors that identify lane markings. The difference between LDW and LKAS is that LDW merely warns drivers that they are unintentionally leaving their lane via visual, auditory, and tactile warnings. LKAS will physically guide the car back to the center of the lane if the driver does not heed the LDW warnings.

Adaptive Cruise Control (ACC)

Perhaps one of the most impressive ADAS integrations is that between LKAS and Adaptive Cruise Control (ACC). ACC functionally works in a similar fashion to LKAS. Using front-mounted sensors, ACC can control the acceleration and the brakes of a vehicle, just as LKAS can control steering and braking.

The level of integration between these two systems is so high, that some may believe that when both are in use, the car is essentially autonomous. It is important to note that even with both of these features functioning at the same time, they both require the driver to continue paying attention and maintain their hands on the steering wheel. Both systems will disengage and send auditory warnings to the driver if hands are removed for too long.

While these features work hand in hand, using primarily the same sensors, they are distinct and may require unique calibration care.

LKAS vs Lane Centering

The subtle difference between LKAS and Lane Centering features is noteworthy for the sake of addressing systems correcting while calibrating. LKAS activates when its sensors detect that the vehicle has unintentionally left the lane. It then recenters the vehicle in the correct lane. Lane Centering is a feature that ensures the vehicle stays in the exact center of the lane at all times, making small adjustments continuously.

Common calibration scenarios for LKAS

Understanding when your shop needs to calibrate LKA systems and related sensors is vital. You could be held liable for missed or improperly calibrated ADAS features. With the wide variance in LKA systems among makes and models, checking OEM standards for the specific vehicle in your shop is a must.

That being said, there are some triggers that always warrant LKAS calibration, let’s take a look at what those are.

Calibration triggers

LKA systems need unique care that follow specific OEM requirements, but there are some common triggers that often need to be followed by a calibration of the sensors that power LKAS. These triggers include:

• Suspension work - This work changes the ride height of the vehicle and can throw off the readings of LKAS sensors.
• Collisions that affect ride height - Most collisions warrant a check to ensure ADAS features work as intended, in this specific scenario collisions that affect the ride height of the vehicle can trigger necessary calibrations.
• Windshield repair/replacement - Changing or repairing the windshield can either misalign sensors, or obscure their view. Make sure to ensure sensors placed behind or in windshield arrangements are calibrated after this type of service.

While these are common triggers, they are not the only triggers for LKAS calibration. Be sure to check OEM standards for the specific vehicle that you are servicing. 

You must also know how to calibrate these systems. Read on to make sure you are employing the correct calibration method.

Static vs dynamic calibrations

Understanding when and where to employ static and/or dynamic calibration is also vital when servicing LKASs. These are two distinct calibration methods that can be beneficial for different reasons, and in some cases, both may be required.

Static calibration is work done while the vehicle is stationary. This includes aligning sensors with specific heights and angles with a target board. You will likely need to perform this calibration strategy with LKA systems.

Dynamic calibration is the type of calibration done while the vehicle is moving. Often, road and weather conditions need to be perfect, and other factors specified in the OEMs. This type of calibration is necessary for sensors that take in enough data to recalibrate itself, for example, driving ten miles so the LKAS can properly identify lane markings. 

These two distinct methods are different in equipment and spatial needs, but you will likely need to employ both of these when calibrating an LKAS.

The future of LKAS systems

Studies point to a massive uptick in LKAS integration in the near future. One forecast estimates an annual market growth rate of 15.9%, reaching a market size of over $22 billion by 2033. This massive expansion is due in part to the success of LKAS in reducing fatal crashes by 24% in a 2024 study conducted by the National Highway Traffic Safety Administration (NHTSA).

Another reason for this expected growth in the LKAS market is the overall explosion in ADAS integration. Already, over 90% of new vehicles have at least one ADAS feature, and that will soon be 100% with the enforcement of NHTSA’s FMVSS 127 which will mandate all new cars have Automatic Emergency Braking.

All of this evidence points to the absolute necessity in understanding LKA systems and their calibration needs. Your shop will have to perform this type of work so it is vital you know how to do it correctly, or you risk being liable for malfunctions, losing customers, and losing out on profit.

How Revv streamlines your LKAS calibration process

Finding OEM standards for calibrating LKAS or any other ADAS feature can take hours of sifting through databases and is overall a waste of time..

Instead of spending valuable hours searching endlessly for OEM requirements, Revv has already done this research for you. With Revv, you can instantly get:

• Instant identification of required calibrations
• Detailed OEM procedures 
• Comprehensive documentation tools
• Integrations with existing shop systems

Since Revv has already done the heavy lifting, your shop can focus on calibrating with confidence and getting the job done right the first time.

Are you looking to enhance your LKAS calibration process? Set up a call with our team and see how Revv can improve your shop by capturing more revenue and keeping your customers safe.