Lane centering keeps the vehicle centered in the lane and almost always comes with steering assist to help the vehicle take gentle turns at highway speeds.[10] Lane departure warning generates a warning when the vehicle crosses a line, while lane keeping assist helps the vehicle to avoid crossing a line, standardized in ISO 11270:2014.[11]
In farming, "machine autosteer" is a technology which make automated steering and positioning of a machine in a landscape.[12]
Comparing standard systems assisting with lateral control[13]
Name
SAE level
Description
ACSF category
Automotive market name
Emergency steering function - ESF
SAE L0 - no driving automation
“automatically detect a potential collision and automatically activate the vehicle steering system for a limited duration, to steer the vehicle with the purpose of avoiding or mitigating a collision.” Reg 79
Lane departure warning - LDW
SAE L0 - no driving automation
warns “the driver of an unintentional drift of the vehicle out of its travel lane.” Reg 130.
Usually with lane departure avoidance (LDA)
Lane departure avoidance - LDA
SAE L0 - no driving automation
“corrects the steering angle to prevent departure from the chosen lane” although (limited duration). Reg 79
Corrective Steering Function (CSF),
ACSF B1,
Lane Keeping Assistance System (LKA/LKS): ISO 7000-3128
Lane Departure Prevention (LDP)
B1
LKA/LKS
Emergency Lane Keeping System - ELKS
-
combination of LDW and LDA, EU General Safety Regulation [Regulation (EU) 2019/2144] and European Commission Implementing Regulation [Regulation (EU) 2021/64] specification.
Lane guidance
SAE L1 - assisted driving
adaptive application of some steering to reduce the effort required by the driver in keeping their vehicle centered in the lane.
B1
LKA or Lane Centring Assistance (LCA)
Lane keeping
SAE L2 - partially automated driving
keep the vehicle in the center of its current lane, reducing driver input
B1
LKA or LCA
Lane change system
SAE L2 - partially automated driving
after initial command or confirmation by the driver, automatically applies steering to move the vehicle to an adjacent lane
C
Auto Lane Change or (Highway/Active) Lane Change Assist
History
The first commercially available lane centering systems were based on off-the-shelf systems created by Mobileye, such as Tesla Autopilot and Nissan ProPilot,[14] although Tesla switched to an in-house design when Mobileye ended their partnership.[15] A handful of companies like Bosch, Delphi, ZF and Mobileye provide sensors, control units, or algorithms to car makers, who then integrate and refine those systems.[16]
While not directly attributable to lane centering, crash rates on the Tesla Model S and Model X equipped with the Mobileye system were reduced by almost 40% while Tesla Autopilot was in use.[17][18][19]
Operation
Lane detection algorithmAn example implementation of the lane detection algorithm showing Canny edge detection and Hough transform outputs
The lane detection system used by the lane departure warning system uses image processing techniques to detect lane lines from real-time camera images fed from cameras mounted on the automobile. Examples of image processing techniques used include the Hough transform, Canny edge detector, Gabor filter and deep learning. A basic flowchart of how a lane detection algorithm works to produce lane departure warning is shown in the figures.
Limitations
Features that differentiate systems include how well they perform on turns, speed limitations, and whether the system resumes from a stop.[20][21]
Current lane centering systems rely on visible lane markings. They typically cannot decipher faded, missing, incorrect or overlapping lane markings. Markings covered in snow, or obsolete lane markings left visible, can affect the accuracy of the system.[22]
GM's Super Cruise only works on known freeways that have been previously mapped,[23] as it uses a combination of these maps and a precise GNSS position provided by Trimble's RTX GNSS correction service to determine if Super Cruise can be enabled or not.[23] Most vehicles require the driver's hands to remain on the wheel, but GM's Super Cruise monitors the driver's eyes to ensure human attention to the road,[24] and thus allows hands-free driving.
2018 Mobileye EyeQ4
Mobileye claimed in 2018 that 11 automakers would incorporate their EyeQ4 chip that enables L2+ and L3 autonomous systems; this would collectively represent more than 50% of the auto industry.[25] Level 2 automation is also known as "hands off": this system takes full control of the vehicle (accelerating, braking, and steering). Level 3 is also known as "eyes off": the driver can safely turn their attention away from driving, e.g. the driver can text or watch a movie.[26]
In 2018, the average selling price for the EyeQ4 chip to auto makers was about $450 U.S. dollars.[27]
Nissan uses the EyeQ4 chip for their hands-off ProPilot 2.0 system.[28]
Territories such as the European union, Japan, Russia, Turkey, Egypt and the United Kingdom follow UNECE 79 regulation.[30] In those territories following UNECE 79 regulation, automatically commanded steering functions are classified in several categories, for instance:
Category A function helps the driver at speed no greater than 10 km/h for parking maneuvering;
Category B1 function helps the driver to keep the vehicle within the chosen lane;
Category B2 function "keeps the vehicle within its lane by influencing the lateral movement of the vehicle for extended periods without further driver command/confirmation";
Category C and D and E are related to specific manoeuvres such as lane change[31]
While all those functions are related to automated steering, lane centering is a concept close to the concept related to category B2, while LKA is closer to category B1.
Current international regulations require assistance systems to monitor that the driver keeps their hands on the steering wheel, with escalating warnings and eventual disengagement if they fail to do so. In North America, some manufacturers have "hands-off" systems which instead monitor whether the driver is paying attention to the road ahead.[32]
Because all of these vehicles also have adaptive cruise control that can work in tandem with lane centering, they meet the SAE standard for level 2 automation. Adaptive cruise control and lane centering are often only available in more expensive trim levels rather than just the base trim. An example is the Hyundai Kona EV, which only has adaptive cruise control available on the "ultimate" edition.[33]
Nissan ProPilot is based on Mobileye technology[128] and assists with acceleration, steering and braking input under single lane highway driving conditions.[129] ProPilot keeps the car centered in the lane and will deactivate below 31 mph if not tracking a car in front of it.[97] Adaptive cruise control handles stop-and-go traffic if stopped for less than 4 seconds[130] and helps maintain a set vehicle speed and maintain a safe distance between the vehicle ahead. ProPilot, which can follow curves,[131] uses a forward-facing camera, forward-facing radar and other sensors. A traffic sign recognition system provides drivers with the most recent speed limit information detected by a camera on the windshield, in front of the rear-view mirror.
In a review by ExtremeTech, ProPilot worked well in 1,000 miles of testing and only on some twisty sections did it require driver intervention.[132] During Euro NCAP 2018 testing, ProPilot failed some tests as did all other systems tested.[133][134]Consumer Reports indicates that ProPilot is especially helpful in stop and go traffic.[135]
Honda Sensing/AcuraWatch
Honda Sensing and AcuraWatch are a suite of advanced driver assistance features including Lane Keeping Assist System (LKAS) which helps keep the vehicle centered in a lane, by applying mild steering torque if the vehicle is deviating from the center of a detected lane with no turn-signal activation by the driver.[136][137] Mild steering torque means the system will not work on tight turns; additionally, the system does not work at speeds below 45 mph. The Honda Sensing and AcuraWatch packages also include:
We're not ready to say yet which company has the safest implementation of Level 2 driver assistance, but it's important to note that none of these vehicles is capable of driving safely on its own...
The report indicated that only the Tesla Model 3 stayed within the lane on all 18 trials.
Quote from the report:
The evidence for safety benefits of active lane-keeping systems isn't as pronounced as for ACC. Still, the potential to prevent crashes and save lives is large. IIHS research shows that preventing lane-departure crashes could save nearly 8,000 lives in a typical year...
^"The 2019 Nautilus: Lincoln's Cadillac Super Cruise fighter?". Automotive News. September 21, 2018. Retrieved December 28, 2018. ... the Nautilus with semi-autonomous technology that can maneuver the vehicle down the freeway without the need for a driver to touch the brake, gas pedal or steering wheel for short periods.
^"2018 Honda Odyssey Owner's Manual"(PDF). techinfo.honda.com. pp. 581–588. Retrieved November 24, 2018. Provides steering input to help keep the vehicle in the middle of a detected lane
^"Vehicle settings". webmanual.hyundai.com. Retrieved January 26, 2019. [Lane Following Assist]: It supports by automatically operating steering wheel to drive in the center of the lane.
^ abc"Kia's all electric crossover, Niro goes on sale in South Korea". Automotive Purchasing and Supply Chain. July 20, 2018. Retrieved January 26, 2019. Lane Following Assist tracks vehicles in front of the car in traffic, and detects road markings to keep the Niro EV in its lane on the motorway.
