![Strada Provinciale BS 510 Sebina Orientale](https://upload.wikimedia.org/wikipedia/commons/7/76/Strada_Provinciale_BS_510_Sebina_Orientale.jpg)
In road-transport terminology, a lane departure warning system (LDWS) is a mechanism designed to warn the driver when the vehicle begins to move out of its
lane
In road transport, a lane is part of a roadway that is designated to be used by a single line of vehicles to control and guide drivers and reduce traffic conflicts. Most public roads (highways) have at least two lanes, one for traffic in each ...
(unless a
turn signal
The lighting system of a motor vehicle consists of lighting and signalling devices mounted to or integrated into the front, rear, sides, and in some cases the top of a motor vehicle. They illuminate the road ahead for the driver and increase th ...
is on in that direction) on
freeway
A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms ...
s and
arterial road
An arterial road or arterial thoroughfare is a high-capacity urban road that sits below freeways/motorways on the road hierarchy in terms of traffic flow and speed. The primary function of an arterial road is to deliver traffic from collector ro ...
s. These systems are designed to minimize accidents by addressing the main causes of collisions: driver error, distractions and drowsiness. In 2009 the U.S.
National Highway Traffic Safety Administration
The National Highway Traffic Safety Administration (NHTSA ) is an agency of the U.S. federal government, part of the Department of Transportation. It describes its mission as "Save lives, prevent injuries, reduce vehicle-related crashes" rela ...
(NHTSA) began studying whether to mandate lane departure warning systems and
frontal collision warning systems on automobiles.
There are four types of systems:
*Lane departure warning (LDW): Systems which warn the driver if the vehicle is leaving its lane with visual, audible, and/or vibration warnings
*
Lane keeping assist
In road-transport terminology, a lane departure warning system (LDWS) is a mechanism designed to warn the driver when the vehicle begins to move out of its lane (unless a turn signal is on in that direction) on freeways and arterial roads. These ...
(LKA/LKS): Systems which warn the driver and, with no response, automatically take steps to ensure the vehicle stays in its lane
*
Lane centering assist (LCA): Systems which assist in oversteering, keeping the car centered in the lane, and asking the driver to take over in challenging situations
*
Automated lane keeping systems
Automated lane keeping systems (ALKS), also described as traffic jam chauffeur, is an autonomous driving system that doesn't require driver supervision on motorways. ALKS is an international standard set out in UN-ECE regulation 157 and amounts ...
(ALKS)
Another system is the emergency lane keeping (ELK). The emergency lane keeping applies correction to a vehicle which drift beyond a solid lane marking.
[https://cdn.euroncap.com/media/29410/euro-ncap-lss-test-protocol-v20.pdf ]
Rationale
One of the main causes of
single vehicle crashes and
frontal crashes is lane departure. The goal of the lateral support systems (LSS) is to help to avoid such crashes.
Without those LSS systems, lane departure can be unintentional; the car drifts towards and across the edge of the lane. The car then reach a potentially dangerous situation.
This system does not work when the edge of the lane is not marked by a line.
Sensor types
![Lane Guidance Camera PCB](https://upload.wikimedia.org/wikipedia/commons/9/96/Lane_Guidance_Camera_PCB.jpg)
Lane warning/keeping systems are based on:
*Video sensors in the visual domain (mounted behind the windshield, typically integrated beside the rear mirror)
*Laser sensors (mounted on the front of the vehicle)
*Infrared sensors (mounted either behind the windshield or under the vehicle)
Working principle
![Lane_Detection_Example](https://upload.wikimedia.org/wikipedia/commons/3/3f/Lane_Detection_Example.jpg)
A lane detection system used behind the lane departure warning system uses the principle of
Hough transform
The Hough transform is a feature extraction technique used in image analysis, computer vision, and digital image processing. The purpose of the technique is to find imperfect instances of objects within a certain class of shapes by a voting pro ...
and
Canny edge detector to detect lane lines from realtime camera images fed from the front-end camera of the automobile. A basic flowchart of how a lane detection algorithm works to help lane departure warning is shown in the figures.
Lane marking
In Europe, the lane departure warning system should be compatible with a visible lane marking identification standard such as commission regulation EU-351/2012.
History
The concept and a working model of this technology was invented and fitted to a Rover SD1 in England by British inventor Nick Parish in 1988. Patent application No 8911571.1 was made in 1989.
The first production lane departure warning system in Europe was developed by the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
company Iteris for
Mercedes Actros commercial trucks. The system debuted in 2000, and is now available on many new cars, SUVs, and trucks.
In 2002, the Iteris system became available on
Freightliner Trucks
Freightliner Trucks is a US semi truck manufacturer. Founded in 1929 as the truck-manufacturing division of Consolidated Freightways (from which it derives its name), the company was established in 1942 as Freightliner Corporation. Owned by Dai ...
' North American vehicles. In both these systems, the driver is warned of unintentional lane departures by an audible
rumble strip
Rumble strips (also known as sleeper lines or alert strips) are a road safety feature to alert inattentive drivers of potential danger, by causing a tactile vibration and audible rumbling transmitted through the wheels into the vehicle interior. ...
sound generated on the side of the vehicle drifting out of the lane. No warnings are generated if, before crossing the lane, an active turn signal is given by the driver.
2001
Nissan Motors
, trading as Nissan Motor Corporation and often shortened to Nissan, is a Japanese multinational automobile manufacturer headquartered in Nishi-ku, Yokohama, Japan. The company sells its vehicles under the Nissan, Infiniti, and Datsun brands, ...
began offering a lane-keeping support system on the
Cima sold in Japan.
2002
Toyota
is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...
introduced its lane monitoring system on models such as the
Caldina
The is an automobile manufactured by Toyota for the Japanese market from 1992 to 2007. It replaced the Corona and Carina wagons, and was sold at ''Toyota Store'' and ''Toyopet Store'' locations in Japan. While the Caldina has never been official ...
and
Alphard
Alphard , designated Alpha Hydrae (α Hydrae, abbreviated Alpha Hya, α Hya), is the brightest star in the constellation of Hydra. It is a single giant star, cooler than the Sun but larger and more luminous. It is about 177 light-year ...
sold in Japan; this system warns the driver if it appears the vehicle is beginning to drift out of its lane.
2003
Honda
is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan.
Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...
launched its Lane Keep Assist System (LKAS) on the
Inspire
The following is a thematic list of European Union directives:
For a date based list, see the :European Union directives by number
Numbering
From 1 January 1992 to 31 December 2014, numbers assigned by the General Secretariat of the Council ...
. It provides up to 80% of steering torque to keep the car in its lane on the highway. It is also designed to make highway driving less cumbersome, by minimizing the driver's steering input. A camera, mounted at the top of the windshield just above the
rear-view mirror
A rear-view mirror (or rearview mirror) is a flat mirror in automobiles and other vehicles, designed to allow the driver to see rearward through the vehicle's rear window (rear windshield).
In cars, the rear-view mirror is usually affixed to ...
, scans the road ahead in a 40-degree radius, picking up the dotted white lines used to divide lane boundaries on the highway. The computer recognizes that the driver is "locked into" a particular lane, monitors how sharp a curve is, and uses factors such as yaw and vehicle speed to calculate the steering input required.
2004
In 2004, the first passenger-vehicle system available in North America was jointly developed by Iteris and
Valeo
Valeo is a French global automotive supplier headquartered in France, listed on the Paris Stock Exchange ( CAC-40 Index). It supplies a wide range of products to automakers and the aftermarket. The Group employs 113,600 people in 33 countries wo ...
for Nissan on the
Infiniti FX
The Infiniti QX70, formerly called the Infiniti FX until 2013, is a mid-size luxury crossover SUV produced by the Nissan-owned Infiniti luxury vehicle brand between 2002 and 2017. The FX replaced the QX4 as Infiniti's mid-size SUV. It shares the ...
and (in 2005) the
M vehicles. In this system, a camera (mounted in the overhead console above the mirror) monitors the lane markings on a roadway. A warning tone is triggered to alert the driver when the vehicle begins to drift over the markings. Also in 2004, Toyota added a lane keeping assist feature to the
Crown Majesta
The is a full-size luxury sedan from Toyota. It is an upmarket variant of the Crown and serves as Toyota's flagship model in various countries.
The Crown Majesta appeared after the international introduction of the Celsior/Lexus LS in late 1 ...
which can apply a small counter-steering force to aid in keeping the vehicle in its lane.
2005
Citroën
Citroën () is a French automobile brand. The "Automobiles Citroën" manufacturing company was founded in March 1919 by André Citroën. Citroën is owned by Stellantis since 2021 and previously was part of the PSA Group after Peugeot acquired ...
became the first in Europe to offer LDWS on its 2005
C4 and
C5 models, and its
C6. This system uses infrared sensors to monitor lane markings on the road surface, and a vibration mechanism in the seat alerts the driver of deviations.
2006
Lexus
is the luxury vehicle division of the Japanese automaker Toyota. The Lexus brand is marketed in more than 90 countries and territories worldwide and is Japan's largest-selling make of premium cars. It has ranked among the 10 largest Japanese ...
introduced a multi-mode lane keeping assist system on the
LS 460
The is a full-size car, full-size luxury car, luxury sedan (F-segment in Europe) serving as the Core product, flagship model of Lexus, the luxury division (business), division of Toyota. For the first four generations, all LS models featured V8 ...
, which utilizes stereo cameras and more sophisticated object- and pattern-recognition processors. This system can issue an audiovisual warning and also (using the
electric power steering or EPS) steer the vehicle to hold its lane. It also applies counter-steering torque to help ensure the driver does not over-correct or "saw" the steering wheel while attempting to return the vehicle to its proper lane. If the
radar cruise control system is engaged, the Lane Keep function works to help reduce the driver's steering-input burden by providing steering torque; however, the driver must remain active or the system will deactivate.
2007
In 2007,
Audi
Audi AG () is a German automotive manufacturer of luxury vehicles headquartered in Ingolstadt, Bavaria, Germany. As a subsidiary of its parent company, the Volkswagen Group, Audi produces vehicles in nine production facilities worldwide.
Th ...
began offering its Audi lane assist feature for the first time on the
Q7. This system, unlike the Japanese "assist" systems, will not intervene in actual driving; rather, it will vibrate the steering wheel if the vehicle appears to be exiting its lane. The LDW System in Audi is based on a forward-looking video-camera in its visible range, instead of the downward-looking infrared sensors in the Citroën. Also in 2007, Infiniti offered a newer version of its 2004 system, which it called the Lane Departure Prevention (LDP) system. This feature utilizes the vehicle
stability control
Electronic stability control (ESC), also referred to as electronic stability program (ESP) or dynamic stability control (DSC), is a computerized technology that improves a car handling, vehicle's stability by detecting and reducing loss of Tract ...
system to help assist the driver maintain lane position by applying gentle brake pressure on the appropriate wheels.
2008
General Motors
The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and ...
introduced Lane Departure Warning on its 2008 model-year
Cadillac
The Cadillac Motor Car Division () is a division of the American automobile manufacturer General Motors (GM) that designs and builds luxury vehicles. Its major markets are the United States, Canada, and China. Cadillac models are distributed i ...
STS
STS, or sts, may refer to:
Medicine
* Secondary traumatic stress, a condition which leads to a diminished ability to empathize
* Sequence-tagged site, a gene-reference in genomics
* Soft-tissue sarcoma
* Staurosporine, an antibiotic
* STS (gen ...
,
DTS, and
Buick Lucerne models. The General Motors system warns the driver with an audible tone and a warning indicator on the dashboard.
BMW also introduced Lane Departure Warning on the
5 Series (E60) and
6 Series, using a vibrating steering wheel to warn the driver of unintended departures. In late 2013 BMW updated the system with Traffic Jam Assistant appearing first on the redesigned
BMW X5
The BMW X5 is a mid-size luxury SUV produced by BMW. The X5 made its debut in 1999 as the E53 model. It was BMW's first SUV. At launch, it featured all-wheel drive and was available with either a manual or automatic gearbox. The second generatio ...
, this system works below .
Volvo
The Volvo Group ( sv, Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distributio ...
introduced the lane departure warning system and the driver alert control on its 2008 model-year
S80, the
V70, and
XC70 executive car
Executive car is a British term for a large car which is equivalent to the European E-segment and American full-size classifications. Executive cars are larger than compact executive cars (and the non-luxury equivalent mid-size cars), and small ...
s. Volvo's lane departure warning system uses a camera to track road markings and sound an alarm when drivers depart their lane without signaling. The systems used by BMW, Volvo, and General Motors are based on core technology from
Mobileye
Mobileye Global Inc. is a company developing autonomous driving technologies and advanced driver-assistance systems (ADAS) including cameras, computer chips and software. Mobileye was acquired by Intel in 2017 and went public again in 2022. Mobi ...
.
2009
Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartere ...
began offering a Lane Keeping Assist function on the new
E-class. This system warns the driver (with a steering-wheel vibration) if it appears the vehicle is beginning to leave its lane. Another feature will automatically deactivate and reactivate if it ascertains the driver is intentionally leaving his lane (for instance, aggressively cornering). A newer version will use the braking system to assist in maintaining the vehicle's lane.
2010
Kia Motors
Kia Corporation, commonly known as Kia (, ; formerly known as Kyungsung Precision Industry and Kia Motors Corporation), is a South Korean multinational automobile manufacturer headquartered in Seoul, South Korea. It is South Korea's second lar ...
offered the 2011 Cadenza premium sedan with an optional lane departure warning system (LDWS) in limited markets. This system uses a flashing dashboard icon and emits an audible warning when a white lane marking is being crossed, and emits a louder audible warning when a yellow-line marking is crossed. This system is canceled when a turn signal is operating, or by pressing a deactivation switch on the dashboard; it works by using an optical sensor on both sides of the car.
2011
Audi A7
The Audi A7 is an executive luxury four-door coupé produced by Audi since 2010. A five-door liftback (also available as a three-box, four-door saloon in China since 2021), it features a sloping roofline with a steeply raked rear window and inte ...
introduces Audi active lane assist.
2012
Mobileye
Mobileye Global Inc. is a company developing autonomous driving technologies and advanced driver-assistance systems (ADAS) including cameras, computer chips and software. Mobileye was acquired by Intel in 2017 and went public again in 2022. Mobi ...
developed a system that detected
lane markings
In road transport, a lane is part of a roadway that is designated to be used by a single line of vehicles to control and guide drivers and reduce traffic conflicts. Most public roads (highways) have at least two lanes, one for traffic in each ...
, and identified when a vehicle departed from its driving lane without the use of the turn signal.
2013
Mercedes began Distronic Plus with Steering Assist and Stop&Go Pilot on the redesigned S-class in 2013.
2014
Tesla Model S comes with advanced lane assistance systems with their 2014 release. It was also released with a speed assist feature where the front facing camera reads the traffic speed limits using the technology of
computer vision
Computer vision is an interdisciplinary scientific field that deals with how computers can gain high-level understanding from digital images or videos. From the perspective of engineering, it seeks to understand and automate tasks that the hum ...
character recognition system, and then conveys it to the car. On roads where traffic signs are absent, it relies on the GPS data. When the car moves away from a lane at above , the system beeps and the steering wheel vibrate, alerting the driver of an unintended lane change. This happens during speed limit non-compliance as well.
Fiat is launching its lane keep assist feature based on TRW's lane keeping assist system (also known as the haptic lane feedback system). This system integrates the lane-detection camera with TRW's electric power-steering system; when an unintended lane departure is detected (the turn signal is not engaged to indicate the driver's desire to change lanes), the electric power-steering system will introduce a gentle torque that will help guide the driver back toward the center of the lane. Introduced on the Lancia Delta in 2008, this system earned the Italian Automotive Technical Association's Best Automotive Innovation of the Year Award for 2008.
Peugeot
Peugeot (, , ) is a French brand of automobiles owned by Stellantis.
The family business that preceded the current Peugeot companies was founded in 1810, with a steel foundry that soon started making hand tools and kitchen equipment, and the ...
introduced the same system as Citroën in its new
308.
Lane departure warning systems combine prevention with risk reports in the transportation industry. Viewnyx applies video-based technology to assist fleets in lowering their driving liability costs. By providing safety managers with driver- and fleet-risk assessment reports and tools, it facilitates proactive coaching and training to eliminate high-risk behaviors. The Lookout Solution is used by North American fleets, and there is research on implementing a lane departure warning system via a mobile phone.
2017
An Insurance Institute for Highway Safety raised concern that drivers may be less vigilant when relying on automated safety systems or become distracted by dashboard displays that monitor how the systems are performing.
Two separate studies found that lane-keeping systems and blind spot monitoring systems had lower crash rates than the same vehicles without the systems. Police crash data from 25 states between 2009 and 2015 for vehicle models where the systems were sold as optional reduced rates of single-vehicle, sideswipe, and head-on crashes by 11 percent, and injuries in such crashes by 21 percent. The sample size was not large enough to control for demographic and other variables.
Lane keeping and next technologies
Lane keeping assist (LKA) is a feature that, in addition to the lane departure warning system, automatically takes steps to ensure the vehicle stays in its lane. Some vehicles combine
adaptive cruise control
Adaptive cruise control (ACC) is an available cruise control Advanced driver-assistance systems, advanced driver-assistance system for road vehicles that automatically adjusts the vehicle speed to maintain a safe distance from vehicles ahead. As ...
with lane keeping systems to provide additional safety.
While the combination of these features creates a semi-autonomous vehicle, most require the driver to remain in control of the vehicle while it is in use. This is because of the limitations associated with the lane-keeping feature.
[
The lane keeping assist system is being achieved in modern vehicle systems using image processing techniques called ]Hough transform
The Hough transform is a feature extraction technique used in image analysis, computer vision, and digital image processing. The purpose of the technique is to find imperfect instances of objects within a certain class of shapes by a voting pro ...
and Canny edge detection techniques. These advanced image processing techniques derive lane data from forward facing cameras attached to the front of the vehicle. Real-time image processing using powerful computers like Nvidia
Nvidia CorporationOfficially written as NVIDIA and stylized in its logo as VIDIA with the lowercase "n" the same height as the uppercase "VIDIA"; formerly stylized as VIDIA with a large italicized lowercase "n" on products from the mid 1990s to ...
's Drive PX1 are being used by many vehicle OEMs to achieve fully autonomous vehicles in which lane detection algorithm plays a key part. Advanced lane detection algorithms are also being developed using deep learning
Deep learning (also known as deep structured learning) is part of a broader family of machine learning methods based on artificial neural networks with representation learning. Learning can be supervised, semi-supervised or unsupervised.
De ...
and neural network
A neural network is a network or circuit of biological neurons, or, in a modern sense, an artificial neural network, composed of artificial neurons or nodes. Thus, a neural network is either a biological neural network, made up of biological ...
techniques. Nvidia has achieved high accuracy in developing self-driving features including lane keeping using the neural network based training mechanism in which they use a front facing camera in a car and run it through a route and then uses the steering input and camera images of the road fed into the neural network and make it 'learn'. The neural network then will be able to change the steering angle based on the lane change on the road and keep the car in the middle of the lane.
A lane keeping assist mechanism can either reactively turn a vehicle back into the lane if it starts to leave or proactively keep the vehicle in the center of the lane. Vehicle companies often use the term "lane keep(ing) assist" to refer to both reactive lane keep assist (LKA) and proactive lane centering
In road-transport terminology, lane centering, also known as auto steer or autosteer, is an advanced driver-assistance system that keeps a road vehicle centered in the lane, relieving the driver of the task of steering. Lane centering is simil ...
assist (LCA) but the terms are beginning to be differentiated.
Tesla uses the most advanced lane assist system (kind of LKA) combined with their adaptive cruise control system marketed together as 'Autopilot
An autopilot is a system used to control the path of an aircraft, marine craft or spacecraft without requiring constant manual control by a human operator. Autopilots do not replace human operators. Instead, the autopilot assists the operator' ...
'.
In 2020, UNECE released an automated lane keeping system
Automated lane keeping systems (ALKS), also described as traffic jam chauffeur, is an autonomous driving system that doesn't require driver supervision on motorways. ALKS is an international standard set out in UN-ECE regulation 157 and amounts ...
(ALKS) regulation which include features such as lane-keeping and adaptative speed for specific roads up to 60 km/h.
Tesla includes features like lane-keeping assist and also automatic lane changing without driver input. A similar technology to lane assist is used to do autopark feature as well.
Vehicles
Requires driver control while vehicle is in use, but adjusts steering if vehicle detects itself drifting out of lane ((LKA) refers to reactive "lane keep(ing) assist" and (LCA) refers to proactive lane centering):
List shows up to 2015 model year. This feature has become more widespread since then, as seen below.
Allows unassisted driving under limited conditions
Limitations
Lane departure warning systems and lane keeping systems rely on visible lane markings. They typically cannot decipher faded, missing, or incorrect lane markings. Markings covered in snow or old lane markings left visible can hinder the ability of the system.
UNECE regulation 130 does not require LDWS of heavy vehicles to work under 60 km/h or to work in a curve with a radius lower than 250 meters.
Lane departure warning systems also face many legal limitations regarding autonomous driving. As stated previously, this system requires constant driver input. Vehicles with this technology are limited to assisting the driver, not driving the vehicle. Lane departure warning systems biggest limitation is that it is not in complete control of the vehicle. The system does not take into account other vehicles on the road and "cannot replace good driving habits".
Potential danger
American Automobile Association testers found advanced driver assistance systems inconsistent and dangerous. Systems performed 'mostly as expected', but when approaching a simulated disabled vehicle a collision occurred 66 per cent of the time and the average impact speed was 25 mph (40kmh).
See also
*Autonomous car
A self-driving car, also known as an autonomous car, driver-less car, or robotic car (robo-car), is a car that is capable of traveling without human input.Xie, S.; Hu, J.; Bhowmick, P.; Ding, Z.; Arvin, F.,Distributed Motion Planning for S ...
*Adaptive cruise control
Adaptive cruise control (ACC) is an available cruise control Advanced driver-assistance systems, advanced driver-assistance system for road vehicles that automatically adjusts the vehicle speed to maintain a safe distance from vehicles ahead. As ...
* Blind spot monitor
*Intelligent car
Vehicular automation involves the use of mechatronics, artificial intelligence, and multi-agent systems to assist the operator of a vehicle (car, aircraft, watercraft, or otherwise).Hu, J.; Bhowmick, P.; Lanzon, A.,Group Coordinated Control o ...
*Lane centering
In road-transport terminology, lane centering, also known as auto steer or autosteer, is an advanced driver-assistance system that keeps a road vehicle centered in the lane, relieving the driver of the task of steering. Lane centering is simil ...
References
External links
Consumer Reports has an extensive list of current vehicles with different safety systems like lane keep assist
{{Autonomous cars and enabling technologies
Advanced driver assistance systems
Warning systems