Lane departure warning systems are not optional. They are required by law on commercial buses longer than 9 meters and trucks weighing more than 20 metric tons, and failure to install them results in a fine. However, in practice, this requirement is more confusing than one might think. Questions arise, such as whether older vehicles need to be retrofitted even though new ones come equipped with the system, why dump trucks are exempt, and what criteria to use when selecting a new device—all because the regulations and device information are scattered across various sources.
So I’ve compiled everything into this single article. The first part covers whether your company’s vehicles are subject to the requirement (scope, exceptions, fines), while the second part explains which devices to install (operating principles and differences by type).
First, here’s the bottom line:
Let’s take a look at each one.
Most people search for “lane departure warning system,” but the official legal term is “lane departure warning system.” In English, it is written as LDWS (Lane Departure Warning System). All three terms refer to the same device.
Of these, the warning system (LDWS)is the one required by law. The importance of this distinction will become clear in the “Comparison of Systems” section below.
Let’s start with a specific scenario.
Mr. Kim, the safety manager at a freight transport company. One Monday morning, while organizing paperwork for a newly contracted leased truck, he suddenly pauses. The 25-metric-ton cargo truck acquired last year came equipped with a warning system right off the assembly line, but he hadn’t checked whether the 2016 model used tractor-trailer that just arrived had one. A colleague sitting next to him chimes in. “I heard you get a fine if it’s not installed. But I think dump trucks are an exception, right?”
This exchange encapsulates the crux of the issue. Mandatory installation depends on the vehicle’s model year and type; while new vehicles come equipped by default , companies must ensure older vehicles in service have the device installed themselves. With exceptions to the rules complicating matters, surprisingly few managers know exactly whether “our vehicles are subject to this requirement.” I’ve summarized the details in the table below.
The requirement for Lane Departure Warning Systems is established by two different laws. If you try to understand these two together, it becomes confusing to determine whether “our car is subject to the requirement.”
| Category | Legal Basis | Scope | Meaning |
|---|---|---|---|
| ① New Vehicle Manufacturing Standards | Article 14-3 of the Rules on the Performance and Standards of Motor Vehicles and Motor Vehicle Parts | Passenger vehicles (excluding subcompact models) and cargo and special-purpose vehicles with a gross vehicle weight exceeding 3.5 metric tons | Installed by the manufacturer at the time of delivery — This is why it comes standard on new large vehicles released recently |
| ② Retrofitting Requirement for Vehicles in Operation | Article 55-2 of the Traffic Safety Act | Commercial passenger vehicles 9 meters or longer, and freight and special-purpose vehicles with a gross vehicle weight exceeding 20 metric tons (expanded as of January 2019 to include freight vehicles with four or more axles, special-purpose freight vehicles, and rescue and special-operation special-purpose vehicles) | Vehicles already in operation must also be retrofitted — this is the responsibility of transportation companies. Fines have been in effect since January 2020 |
To summarize, new large passenger and freight vehicles of recent model years already come equipped with these devices; the issue lies with vehicles that were delivered before the manufacturing standards took effect and are still in operation today. If a vehicle is used for commercial purposes and is either a bus 9 meters or longer or a freight or special-purpose vehicle exceeding 20 metric tons, it is subject to the installation requirement regardless of its age.
In the early stages of the mandate (2017), the focus was on general-purpose freight vehicles with three or fewer axles (cargo trucks and vans), and among special-purpose vehicles, tow trucks (tractors). However, following the amendment to the Enforcement Rules of the Traffic Safety Act in January 2019, the scope was expanded by vehicle type and purpose, and these regulations remain in effect today. Since it is difficult to determine whether your vehicle is subject to the requirement based solely on legal terms such as “four or more axles” or “special-purpose vehicle,” here is a breakdown by specific vehicle type:
| Category | Previous Scope | Expanded Scope (Including Previous Categories) | Actual Vehicle Types That Qualify |
|---|---|---|---|
| Freight trucks | 3 axles or fewer | 4 or more axles | 4 or more axles — including variable axles |
| Standard (cargo truck/van) | Special-purpose | Wing-body, refrigerated trucks, crane trucks, hydraulic loading trucks, live fish transport vehicles | |
| Special-purpose vehicles | 3 axles or fewer | 4 or more axles | 4 or more axles — including variable axles |
| Towing type (tractor) | Rescue Vehicles | Tow truck | |
| Special-purpose vehicles | Moving trucks, ladder trucks, aerial work platforms |
There are two key points to pay special attention to in practice. First, adjustable axles are included in the axle count. Even if there are axles that are normally raised and retracted, the vehicle is still counted as having four axles; therefore, you must check the number of axles on the registration certificate before assuming it is “excluded because it has three axles.” Second, wing-body trucks and refrigerated trucks fall under the “special-purpose” category. While they don’t look much different from standard cargo trucks and are easy to overlook, these are precisely the vehicle types most commonly operated by logistics and food transportation companies—and they are included in the expanded scope.
The following vehicles are exempt from the installation requirement.
Here’s one point for practitioners to note: The statement “dump trucks are exempt” does not mean “dump trucks never have lane departure accidents.” While the law does not mandate installation, the risk of lane departure for dump trucks and trailers traveling on highways remains unchanged. In fact, for vehicles classified as exceptions, it is even more necessary for companies to devise separate safety management measures.
If you are required to install the device but fail to do so, an administrative fine will be imposed. The fine increases with each violation: 500,000 won for the first offense → 1,000,000 won for the second offense → 1,500,000 won for the third offense. This structure is the same as the fines for failing to install a Driving Time Recorder (DTG). You can find details on DTG compliance requirements in the DTG Mandatory Installation Guide.
Many people are still searching for “Lane Departure Warning System Subsidies,” but to put it simply, the government and local government subsidy program for installation costs (covering 80% of installation costs, capped at 400,000 won, and requiring a forward collision warning feature) was a temporary initiative during the early stages of the mandate and has already ended. If you install one now, you’ll generally have to cover the full cost yourself. Occasionally, local governments may launch separate subsidy programs for safety devices, so you can check announcements from your local government.
Lane departure warning systems are manufactured in accordance with international standards (UN R130). Understanding these standards reveals both the capabilities and limitations of the device.
These standards make one thing clear: what the lane departure warning system detects is the “result of the vehicle leaving the lane,” not the “cause of the driver dozing off.” The warning sounds at the final stage—when drowsiness sets in, the head drops, the vehicle drifts, and the vehicle crosses the lane markings.
The background behind making this device mandatory lies in the nature of accidents involving large vehicles.
According to statistics from the National Police Agency’s Traffic Accident Analysis System (TAAS), approximately 98% of traffic accidents are caused by driver factors, with the top single cause being failure to fulfill safety obligations (56.1%), and drowsy driving accounting for the largest share within that category (47.8%). According to statistics from the Korea Road Traffic Authority, the fatality rate for drowsy driving accidents is approximately twice that of general accidents, and according to data from the Korea Expressway Corporation, 71.5% of fatal accidents on expressways result from drowsy driving or inattentiveness. Furthermore, the most common way in which drowsiness and inattention lead to accidents is **lane departure (crossing the center line or rear-ending another vehicle after veering out of the lane)**.
In other words, lane departure warning systems were introduced as “devices that provide one final wake-up call at the very last moment, just before drowsiness or inattention leads to an accident.” The reason these systems are mandatory for buses longer than 9 meters and trucks weighing over 20 metric tons is that accidents involving these vehicles causing a lane departure result in the greatest scale of damage. The overall structure of accident cause statistics was covered in detail in the analysis of accident cause statistics in the transportation industry.
Now it’s time to choose a device. If you search for “lane departure warning system price,” you’ll find a wide range of options—from alarms costing tens of thousands of won to camera-integrated systems costing hundreds of thousands of won. However, before comparing prices, you should first understand that the search results mix devices from three different tiers with varying detection ranges.
| Classification | ① Standalone Warning Device (LDWS) | ② Lane Keeping Assist System (LKAS) | ③ AI Camera-Integrated System |
|---|---|---|---|
| What to Look For | Lane | Lane |
Lane + Vehicles and Pedestrians Ahead + Driver Status (Drowsiness, Failure to Look Ahead, etc.) |
| Actions | Warning | Warning + Steering Assistance | Real-time warnings by hazard type + data logging |
| Detection Point | The moment the vehicle crosses the lane (result) | The moment the vehicle crosses the lane (consequence) | From the moment drowsiness or inattention begins (cause) |
| Compliance with Legal Requirements | Compliance is met if the product meets performance standards | Focused on new car options | Need to verify certification status for each product |
| If compliant | When the goal is to fulfill legal obligations | When purchasing a new car | When the goal is to reduce accidents and ensure safety |
The key difference lies in the timing of intervention. Options ① and ② activate after the “result”—departure from the lane—has already occurred. Option ③ first detects the “cause” of that result—the driver’s eyes closing, nodding off, or failing to look ahead. In fact, a pilot project conducted by the Korea Transportation Safety Authority on route buses (involving 13 transportation companies, 500 buses, 1,615 drivers, and a total operating distance of 1,000 km) found that applying a system that issues real-time warnings regarding the driver’s condition resulted in a 99.7% reductionin drowsy driving, 93.4% in failure to monitor the road ahead, and 46.9% in center line violations. These figures demonstrate that intervening at the root cause stage of lane departure reduces the number of departures themselves.
Regarding the distinction at the system level, we have provided a more in-depth explanation of the differences between ADAS and AI-based safe driving solutions.
These are the items that operational staff should verify before proceeding with installation.
| Questions | Answer |
|---|---|
| Who Must Install It | Commercial buses 9 meters or longer, and freight and special-purpose vehicles with a gross vehicle weight exceeding 20 metric tons (expanded to include freight vehicles with four or more axles, etc.). New vehicles—including all passenger vehicles and freight vehicles exceeding 3.5 metric tons—must be equipped at the manufacturing stage |
| Consequences of Non-Compliance | Fines: 500,000 won for the first offense → 1,000,000 won for the second offense → 1,500,000 won for the third offense |
| Exceptions include | Dump trucks, towed vehicles, and vehicles with standing room |
| Subsidies | Discontinued (a temporary program during the initial mandatory implementation period) |
| When choosing a device, | Focus on detection range over price—does the device only monitor lanes, or does it also identify the cause (driver condition)? |
A lane departure warning is the “final warning” just before an accident. If you want to manage the situation from the very moment drowsiness and inattention begin—long before that warning sounds—an AI-based safe driving solution that includes driver condition detection covers that area. A.I.MATICS’ Roadscope is the system validated in the Korea Transportation Safety Authority pilot project; details can be found in the Driver Monitoring System (DMS) guide.
Based on your fleet inventory, we’ll advise you on which vehicles are subject to the installation requirement and recommend the appropriate configuration to ensure compliance while reducing accidents.
A. You only need to check three items on the vehicle registration certificate: ① whether the vehicle is for commercial use in the “Vehicle Type/Purpose” section; ② length (9 meters or more for passenger vans) or gross vehicle weight (over 20 metric tons for cargo or special-purpose vehicles); and ③ number of axles (subject to the regulation if there are four or more, including variable axles). This also includes special-purpose vehicles such as wing-body trucks, refrigerated trucks, and crane trucks, as well as tow trucks (rescue vehicles), ladder trucks, and aerial work platforms (special-operation vehicles). Conversely, dump trucks, towed trailers, and vehicles with standing room are exempt regardless of the figures listed on the registration certificate. If you own a large number of vehicles, the quickest approach is to create a list categorizing them into the three groups—subject to the requirement, exempt, and already equipped—based on the registration certificate.
A. Administrative fines are imposed cumulatively based on the number of violations: 500,000 won for the first offense, 1 million won for the second, and 1.5 million won for the third. This regulation has been in effect since January 2020. A greater risk than the fines themselves arises after an accident. If a lane departure accident occurs while the mandatory device is not installed, the fact that the company failed to comply with statutory safety measures will remain on record and could work against the company in compensation and administrative penalty proceedings.
A. It is true that dump trucks and trailers are exempt from this legal requirement. However, there is an important distinction to note. The tractor unit pulling the trailer is subject to the requirement, so if you simply assume that “since it’s a trailer, it’s exempt,” you may overlook the obligation for the tractor unit itself. Furthermore, the exemption means that “installation is not mandated,” not that there is no risk; therefore, if you frequently drive on highways, it is worth considering installing the system voluntarily.
A. It’s unlikely. The government program that previously covered 80% of installation costs (up to 400,000 won) was a temporary initiative during the early stages of mandatory implementation (2018–2019) and has since ended; currently, installation is generally at your own expense. However, local governments occasionally launch their own subsidy programs for safety devices in commercial vehicles, so it’s practical to check announcements from your local government and relevant mutual aid associations before installing the device.
A. Yes, it generally does. This is because LKAS is a broader concept that includes the Lane Departure Warning System (LDWS) function. The difference between the two systems is whether it only provides a warning (LDWS) or also assists with steering to help the vehicle return to its lane (LKAS). However, regardless of which system is used, what they detect is the “result of veering out of the lane,” and the causes of that result—drowsiness or failure to monitor the road ahead—fall within the scope of driver monitoring (DMS) systems.
A. It is due to limitations in the system’s operating conditions and detection range. This system activates at speeds of 60 km/h or higher, only when the vehicle has already strayed into another lane. In other words, it does not function at low speeds, and even at high speeds, it cannot intervene during the few seconds after drowsiness sets in and the vehicle begins to drift. There are also cases where the driver fails to react if they are deeply asleep when the warning sounds. Therefore, it is accurate to view this system as a “last line of defense,” and if the goal is to reduce accidents, it is most effective to use it in conjunction with systems that detect the root cause (the driver’s condition).
The legal provisions in this article are based on the Traffic Safety Act, the Rules on the Performance and Standards of Automobiles and Automotive Parts, and press releases from the Ministry of Land, Infrastructure and Transport. The statistics are based on data from the National Police Agency’s Traffic Accident Analysis System (TAAS), the Korea Road Traffic Authority, the Korea Expressway Corporation, and the results of pilot projects conducted by the Korea Transportation Safety Authority. Please check both the specifications listed on your vehicle registration certificate and the latest laws and regulations to determine whether installation is mandatory for your specific vehicle.