Adaptive cruise control (ACC) is a type of advanced driver-assistance system for road vehicles that automatically adjusts the vehicle speed to maintain a safe distance from vehicles ahead. As of 2019, it is also called by 20 unique names that describe that basic functionality. This is also known as Dynamic cruise control.[1]
Control is based on sensor information from sensors. Such systems may use a radar, laser sensor or a camera setup allowing the vehicle to brake when it detects the car is approaching another vehicle ahead, then accelerate when traffic allows it to.
ACC technology is regarded as a key component of future generations of intelligent cars. The technology enhances passenger safety and convenience as well as increasing road capacity by maintaining optimal separation between vehicles and reducing driver errors. Vehicles with autonomous cruise control are considered a Level 1 autonomous car, as defined by SAE International.[2] When combined with another driver assist feature such as lane centering, the vehicle is considered a Level 2 autonomous car.
Adaptive cruise control does not provide full autonomy: the system only provides some help to the driver, but does not drive the car by itself.[3] For example, the driver is able to set the cruise control to 55mph, if the car while traveling that speed catches up to another vehicle going only 45mph, the ACC will cause the car to automatically brake and maintain a safe distance behind the vehicle in front, and will maintain that distance until the road opens up again and the car can safely return to the initially set speed of 55mph.
Given the fact that ACC is considered a key component of future generations of intelligent cars, and the fact that it can increase comfort and safety on longer drives, ACC systems cost anywhere between $500 to $2500, depending on the type of ACC, as well as the model of the car.[4]
Laser-based systems work using LIDAR (Light detection and ranging), allowing laser-based ACC to provide the largest detection distance as well as the best accuracy of all ACC systems.[38] However, laser-based systems do not detect and track vehicles as reliably in adverse weather conditions due to the fact that fog, or water particles in the air may absorb and or redirect the light emitted from the laser, through absorbtion, scattering, and reflection.[39] Laser based ACC systems also have a more difficult time tracking dirty (and therefore non-reflective) vehicles. Laser-based sensors must be exposed, the sensor (a fairly large black box) is typically found in the lower grille, offset to one side.
Radar-based sensors work by emitting a radio wave at a frequency of either 24GHz or 77GHz. As these signals are emitted, the car computes how long it takes for the signal to return, thus finding out how far away a vehicle may be in front of it. Due to the widely distributed beam, radar ACC systems allow for a much wider field of view while still being able to provide accurate measurements of 160+ meters (Roughly 525 feet). These radar systems can be hidden behind plastic fascias; however, the fascias may look different from a vehicle without the feature. For example, Mercedes-Benz packages the radar behind the upper grille in the center and behind a solid plastic panel that has painted slats to simulate the look of the rest of the grille.
Single radar systems are the most common. Systems involving multiple sensors use either two similar hardware sensors like the 2010 Audi A8[40] or the 2010 Volkswagen Touareg,[41] or one central long range radar coupled with two short radar sensors placed on the corners of the vehicle like the BMW 5 and 6 series.[42]
A more recent development is the binocular computer vision system, such as that introduced to the US market in model year 2013 by Subaru. These systems have front-facing video cameras mounted on either side of the rearview mirror and use digital processing to extract depth information from the parallax between the two cameras' views. Due to the fact that there are video cameras, this type of ACC is able to reliably determine shape and classification of objects in front of the vehicle, and are also able to specifically detect when a vehicle in front is braking. As of now, this type of ACC is more widely used for lane centering.
Radar-based ACC is often sold together with a precrash system,[43] which warns the driver and/or provides brake support if there is a high risk of a collision. Also in certain cars, it is incorporated with a lane maintaining system which provides a power steering assist to reduce steering input burden on corners when the cruise control system is activated.
Systems with multiple sensors can practice sensor fusion to integrate the data to improve safety and/or driving experience. GPS data can inform the system of geographic features such as a freeway offramp. A camera system could notice driver behavior such as brake lights and/or a turn signal. This could allow the following car to interpret a turn signal by an exit as not requiring the following car to slow down, as the leading car will exit.[44] Multi-sensor systems could also take note of traffic signs/signals and not, e.g., violate a red light while following a vehicle that crossed before the signal changed.
Predictive systems modify vehicle speed based on predictions of other vehicles' behavior. Such systems can make earlier, more moderate adjustments to the predicted behavior, improving safety and passenger comfort. One example is to predict the likelihood of a vehicle in a neighboring lane moving in front of the controlled vehicle. One system predicts a lane change up to five seconds before it occurs.[45]
Adaptive cruise control is regulated by European norm ISO 15622 Intelligent transport systems—Adaptive cruise control systems—Performance requirements and test procedures.[46]
According to this standard, an ACC is partial automation of longitudinal vehicle control to reduce the workload of the driver on roads where non-motorized vehicles and pedestrians are prohibited. It does not deal with stationary objects.[47]
According to this standard, ACC includes two classes of systems: the FSRA (full speed range) and the LSRA (limited speed range).
The three main categories of ACC are:
| Make | Full speed range ACC | Partial cruise control | |||
|---|---|---|---|---|---|
| Models | Notes | Models | Notes | ||
| Aftermarket | Any Vehicle 1990+ | Uses OpenCV with no braking.Motor Authority Review[48] | |||
| Acura | RLX (2014+), MDX (2014+), TLX (2015+) | 2005 RL, MDX, ZDX, 2016 MDX is 0 mph type, 2016 ILX,[49] RDX[50] | |||
| Alfa Romeo | Giulia (2016+) | Adaptive Cruise Control with Stop & Go[51] | |||
| Audi | A8, A7 (2010+), A6 (2011+); A7 (2013+), Q7 (2007+), A3 Prestige (2013+), Q5 (2013+), A5 (2016+), A4 (2016+) | Adaptive Cruise Control with Stop & Go | |||
| Bentley | Continental GT (2009+) | Follow-to-Stop option | |||
| BMW | 3 and 5-series (2007+), 7-series (2009+), X5 (2011+)[53] excl Diesel, i3 (2014+), X3 (2014+) | Active Cruise Control with Stop & Go (BMW Option Code S5DFA) | Series 7, 5, 6, 3 (2000+), Mini (2014+) | Stop & Go/Lane Assist controls steering for up to 30 seconds of hands-off driving. Highway driving only. Available on 3, 5, 6 and 7 models. (BMW Option Code S541A)Active Cruise Control[54] | |
| Buick | Enclave (2018+), Envision (2017+), Regal/Regal Sportback/ Regal TourX (2016+),[55] Lacrosse (2017+) | Lacrosse (2014–2016),[56] Regal (2014–2015) | |||
| Cadillac | XTS, ATS, SRX (2013+), CTS (2014+), ELR, Escalade/Escalade ESV (2015+ Premium trim) | Also includes full power automatic braking under 20mph (GM Option 'RPO' Code KSG) | 2004 XLR, 2005 STS, 2006 DTS (shuts off below 25mph) | ||
| Chevrolet | Impala (2014+), Malibu (2016+), Volt (2017+), Traverse (2018+ High Country trim only), Tahoe/Suburban (2017+ Premier trim), Blazer (2019+), Equinox (2019+),[57] Silverado (2020+ LT, LTZ and High Country trims)[58] | Adaptive Cruise Control - Advanced with Traffic Jam Assist (GM Option 'RPO' Code KSG) | Tahoe/Suburban (2015-2016 LTZ trim), | Adaptive Cruise Control - Camera, Disables when the vehicle slows to under 10mph (GM Option 'RPO' Code K59) | |
| Chrysler | 200c (2015+), 300 (2015+ in S, C, or C Platinum trims), Pacifica & Pacifica Hybrid (2017+ in Touring L Plus or Limited trims) | Active Cruise Control with Stop & Go.[59] | 2007–2014 300C | Laser, for a limited time, now uses a Bosch radar-based system | |
| Citroen | C4 Picasso & Grand C4 Picasso (2013–22), C5 Aircross | Adaptive Cruise Control with Stop & Go | C4 (2004–10), C4 Picasso (2006–13), Berlingo (2018+), C4 Cactus | ||
| Dodge | Charger (2015+), Challenger (2015+) | Radar, by Bosch | |||
| Ford | Everest (2015+, Trend and Titanium models only),[60] Fusion (2017+), F-150 (2018+), Expedition (2018+), Mustang (2015+, Premium models only), Focus (2018+) | Adaptive cruise control with stop-and-go (optional) | 2015-2017 F150[61] 2011+Explorer, 2017+ Fiesta, 2013+ Ford FLEX, 2006 Mondeo, 2013 Kuga, 2013-2016 Fusion, S-Max, Galaxy, 2010+ Taurus, 2011+ Edge, 2017+ Super Duty, 2019+ Ranger | Disables and does not work or brake under 20mph; - Radar[62] Adaptive Cruise Control and Collision Warning with Brake Support | |
| GMC | Acadia (2017+ Denali), Yukon/Yukon XL (2017+ Denali), Terrain (2019+),[63] Sierra (2020+ SLT, AT4 and Denali) | Adaptive Cruise Control - Advanced with Traffic Jam Assist (GM Option 'RPO' Code KSG) | Yukon/Yukon XL (2015-2016 Denali) | Adaptive Cruise Control - Camera, Disables when the vehicle slows to under 10mph (GM Option 'RPO' Code K59) | |
| Honda | Accord (2018+),[64] CRV (2017+), Available with Honda Sensing package (2016+) | Adaptive Cruise Control (ACC) with Low-Speed Follow | 2003 Inspire, 2005 Legend, 2013 Accord (USA), 2007 CR-V series III, 2015 Honda CRV, 2016+ Honda Pilot,[65] 2018 Honda Odyssey | Adaptive Cruise Control and Collision Mitigating Braking System with Honda Sensing[66] | |
| Hyundai | Azera (2016+), Equus (2012+), Genesis (2015+), Sonata (2015+), Santa Fe (2017+), Santa Fe Sport (2017+), Ioniq (2017+), Palisade (2019+), Ioniq 5 (2022+) | Genesis (2010+), Elantra (2017+) | |||
| Infiniti | EX (2010+)*, Q50 (2014+) | Older laser based system* | Shuts off below 3 mph, EX: in North America as an option, shuts off below 40km/h | ||
| Jaguar | XK8 / XKR (X100) (1999–2006), XK / XKR (X150) (2006–2014), S-Type, XJ, XF | ||||
| Jeep | Cherokee (2014+, Limited and TrailHawk Models), Grand Cherokee (2012+), Wrangler (2018+)[67] | Adaptive Cruise Control (ACC) - Stop/Start again option on 2017 models but not prior models. | 2011–2013 Grand Cherokee (Option on Limited & Overland, standard on Summit) | Radar, by Boschdisengages below 15mph[68] | |
| Kia | Cadenza (2014+), Sedona (2015+), K900 (2015+), Optima (2016+), Sorento (2016+), Niro (2017+), Telluride (2019+), EV6 (2022+) | Advanced Smart Cruise Control (ASCC) | |||
| Land Rover | Range Rover (L405) (2013+) | Range Rover Sport (L320) (2005–2013)Range Rover (L322) (2010–2012) | Above 20mph.Later models (~2010-) can add full speed range by (unofficial) software upgrade.[69] Discovery 3 and 4 can retrofit L320 system with custom mounting hardware[70] | ||
| Lincoln | Continental (2017+),[71] MKZ (2017+)[72] | Adaptive cruise control with stop-and-go. | MKS (2009+), MKT (2010+), MKX (2011+), MKZ (2013+), MKC (2015+) | Radar Adaptive Cruise Control and Collision Warning with Brake Support | |
| Lexus | LS 460 (2006+), GS hybrid (2013+), NX (2015+), NX hybrid (2015+), GS non-hybrid (2016+), RX (2016+), RX hybrid (2016+), UX (2019+),[73] ES (2019+)[74] | Dynamic Radar Cruise Control LS 460 full ACC not available in US until 2013 | 2000 LS430/460 (laser and radar), RX (laser and radar), GS, IS, ES 350, and LX 570 (shuts off below 25mph) | ||
| Mazda | CX-5 (2017+), CX-9 (2017+),[75] Mazda3 (2020+), Mazda CX-30 (2020+), Mazda6 (2021+)[76] | Mazda Radar Cruise Control with Stop and Go | Mazda6 (2014+), Mazda3, CX-5 (2016+) | Radar Cruise Control and Forward Obstruction Warning[77] | |
| Mitsubishi | Outlander (2014+) | ||||
| Mercedes-Benz | S (2006+), B, E, CLS, CL (2009+); A, CLA, M, G, GL (2013+) | Distronic Plus | Distronic | ||
| Nissan | Murano (2015+), Maxima (2016+), Altima (2016+), Sentra (2017+), Note (2017+), Leaf (2018+), Titan (2020+) | Stops vehicle but resets after 3 seconds, requiring brake application to sit still and setting cruise speed again. | 1998 Cima, Primera T-Spec Models | Intelligent Cruise Control (ICC) | |
| Peugeot | 3008 and 5008 (2017+), 308 (2017+), 508 (2018+), 208 (2019+), 2008 (2019+) | Adaptive Cruise Control with Stop & Go | 3008 and 5008 (2009–16), Partner (2018+) | ||
| Porsche | Panamera (2010+); Cayenne (2011+), Cayman (2013+), Boxster(2012+) | Porsche Active Safe (PAS), PDK transmission only. | |||
| Ram | 1500/2500/3500 (2019+) | Adaptive Cruise with Stop | |||
| SEAT | León (2012+), Ateca[78] | ||||
| Skoda | Octavia (2013+), Fabia (2014+), Superb (2014+) | ||||
| Subaru | Legacy, Outback (2013+), Forester (2014+), Impreza (2015+), WRX (2016+), Crosstrek (2016+), Ascent (2019+) | 0 mph EyeSight[79] [80] Non-Radar Camera System | |||
| Suzuki | Swift 2017+ | Vitara (2015+), Sx4 Scross (2016+) | Radar | ||
| Tesla | Model S (late 2014+), Model X, Model 3, Model Y | Traffic-Aware Cruise Control (TACC)[81] with Stop-and-Go | |||
| Toyota | Prius + Prius Prime (2016+), Camry (2018+), C-HR (2018+), Avalon (2017+), Land Cruiser (2018+), Rav 4 (2019+), Corolla (only Hatchback) (2019), Corolla Sedan (2017+) Toyota Safety Sense P (TSS-P), Corolla Sedan and Hatchback (2020+) | Toyota Safety Sense (TSS-P) (on 2017+ Land Cruiser, Avalon and Avalon Hybrid, Prius, Corolla, Prius Prime, RAV4 and RAV4 Hybrid, Highlander and Highlander Hybrid), Toyota Safety Sense (TSS) 2.0 on 2019+ RAV4 and 2020+ Corolla has full speed range. | 1997 Celsior, 2004 Sienna (XLE Limited Edition), Avalon, Sequoia (Platinum Edition), Avensis, 2009 Corolla (Japan),[82] 2017+ Corolla,[83] 2010+ Prius, 2013+ Prius v,[84] 2014+ Highlander,[85] 2015+ Camry,[86] 2016+ RAV4[87] | Dynamic Laser Cruise Control (DLCC) on 2009+ Sienna XLE Limited, Avalon Limited and Sequoia Platinum shuts off below 25mph (US)[88] | |
| Vauxhall / Opel | |||||
| Volkswagen | Phaeton (2010+), Passat B8 (2014+), Touareg (2011+), Golf Mk7 (2013+), Polo (2014+), Jetta (2016+ SEL Trim), Tiguan SEL (2018+), ATLAS SEL (2018+) | Tiguan SEL and ATLAS SEL (2018+) ACC stop-and-go | |||
| Volvo | All Volvo models 2015+ Starting in 2008 ACC was available as an option on V40, S60,[89] V60, XC60, V70, XC70 and S80 | ACC also includes automatic braking. Newest models feature full power auto-brake with pedestrian and cyclist detection. | |||
In 1999, Mercedes introduced Distronic, the first radar-assisted adaptive system, on the Mercedes-Benz S-Class (W220)[10] [90] and the CL-Class.[12] Distronic adjusts the vehicle speed automatically to the car in front in order to always maintain a safe distance to other cars on the road.
In 2005, Mercedes refined the system ("Distronic Plus") making the Mercedes-Benz S-Class (W221) the first car to receive the upgraded system. Distronic Plus could now completely halt the car if necessary on most sedans. In an episode of Top Gear, Jeremy Clarkson demonstrated the effectiveness of the system by coming to a complete halt from motorway speeds to a round-about and getting out, without touching the pedals.
In 2016, Mercedes introduced Active Brake Assist 4, the first emergency braking assistant with pedestrian recognition.[91]
One crash caused by Distronic Plus dates to 2005, when German news magazine "Stern" was testing Mercedes' original Distronic system. During the test, the system did not always manage to brake in time.[92] Ulrich Mellinghoff, then Head of Safety, NVH, and Testing at the Mercedes-Benz Technology Centre, stated that some tests failed because the vehicle was tested in a metallic hall, which caused problems with radar. Later iterations received an upgraded radar and other sensors, which are not disrupted by a metallic environment.[93] In 2008, Mercedes conducted a study comparing the crash rates of Distronic Plus vehicles and vehicles without it, and concluded that those equipped with Distronic Plus have an around 20% lower crash rate.[94]
See main article: openpilot.