Autonomous cruise control (ACC; also called adaptive cruise control, radar cruise control, or traffic-aware cruise control) is an optional cruise control system for road vehicles that automatically adjusts the vehicle speed to maintain a safe distance from vehicles ahead.
Control is based on sensor information from on-board sensors. (No existing system makes use of satellite or roadside infrastructures nor of cooperative support from other vehicles.) Cooperative Adaptive Cruise Control (CACC) further extends the automation of navigation by using information gathered from fixed infrastructure such as satellites and roadside beacons, or mobile infrastructure such as reflectors or transmitters on the back of other vehicles.
They use either a radar or laser sensor setup allowing the vehicle to slow when approaching another vehicle ahead and accelerate when traffic allows.
ACC technology is widely regarded as a key component of any future generations of intelligent cars. They impact driver safety and convenience as well as increasing capacity of roads by maintaining optimal separation between vehicles and reducing driver errors.
Laser- and radar-based systems compete on quality and price.
Laser-based systems do not detect and track vehicles in adverse weather conditions nor do they reliably track 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 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 or the 2010 Volkswagen Touareg, 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.
Radar-based ACC often feature a precrash system, 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 from 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 a 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. 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.
Predict systems modify 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 neighbouring lane moving in front of the controlled vehicle. One system predicts a lane change up to five seconds before it occurs.
1992: Mitsubishi was the first to offer a Lidar-based distance detection system on the Japanese market with its Debonair. Marketed as Distance Warning, this early system warns the driver, without influencing throttle, brakes or gearshifting.
1995: Mitsubishi Diamante introduced laser Preview Distance Control. This early system controlled speed through throttle control and downshifting, not by applying the brakes.
1997: Toyota offered a "laser adaptive cruise control" (lidar) system on the Japanese market Celsior. It controlled speed through throttle control and downshifting, not by applying the brakes.
1998: BMW introduced radar Active Cruise Control in Europe on the BMW 7 Series - E38 (Before makeup)).
1999: Mercedes introduced Distronic, the first radar-assisted ACC, on the Mercedes-Benz S-Class (W220) and the CL-Class.
1999: Jaguar began offering a radar-based Adaptive Cruise Control system on the Jaguar XK (X100).
1999: Nissan introduced laser (lidar) Adaptive Cruise Control on the Japanese market Nissan Cima.
2000: The Lexus division of Toyota was the first to bring laser ACC to the US market in late 2000, with the LS 430's Dynamic Laser Cruise Control system.
2000: Toyota further refined their laser ACC system by adding "brake control", that also applies brakes.
2001: Infiniti introduced laser Intelligent Cruise Control on the 2002 Infiniti Q45 Third generation F50 and 2002 Infiniti QX4.
2001: Renault introduced Adaptive Cruise Control on the Renault Vel Satis (supplied by Bosch)
2002: Lancia introduced radar adaptive cruise control (by Bosch) on the Lancia Thesis
2002: Volkswagen introduced radar ACC, manufactured by Autocruise (now TRW), on the Volkswagen Phaeton.
2002: Audi introduced radar Adaptive cruise control (Autocruise) on the Audi A8 in late 2002
2003: Cadillac introduced radar ACC on the Cadillac XLR.
2003: Toyota shifted from laser (lidar) to radar ACC technology on the Celsior. The first Lexus Dynamic Radar Cruise Control and a radar-guided pre-collision system appeared on the Lexus LS(XF30) US market facelift.
2004: Toyota added "low-speed tracking mode" to the radar ACC on the Crown Majesta. The low-speed speed tracking mode was a second mode that would warn the driver and provide braking if the car ahead stopped; it could stop the car, but would then deactivate.
2005: In the United States, Acura first introduced radar ACC integrated with a Collision avoidance system (Collision Mitigation Braking System (CMBS)) in the model year 2006 Acura RL.
2005: Mercedes-Benz S-Class (W221) refined the Distronic system to completely halt the car if necessary (now called "Distronic Plus" on E-Class and most Mercedes sedans. In an episode of Top Gear, Jeremy Clarkson demonstrated the effectiveness of the cruise control system in the S-class by coming to a complete halt from motorway speeds to a round-about and getting out, without touching the pedals.
2006: Volkswagen Passat B6 introduced ACC. They use radar from Autocruise and TRW, range of speed for ACC 30-210 km/h. Supported additional function AWV1 and AWV2 to prevent collision, it used the brake system.
2006: Audi introduced Full speed range ACC plus on the Audi Q7. It had low-speed mode, warns the driver of a potential collision, and prepare emergency braking as needed. The system supplied by Bosch was available in the 2008 Audi A8, the Audi Q5, 2009 Audi A6 and the new 2010 Audi A8. The Audi A4 was available with an older version of the ACC that did not stop the car completely.
2006: Nissan introduced Intelligent Cruise Control with DISTANCE CONTROL ASSIST on Nissan Fuga. It pushes the gas pedal against the foot when the navigation system observes an unsafe speed. If the Autonomous cruise control system is used, the Distance Control Assistance reduced speed automatically, and warned the driver that with an audible bell sound.
2006: September 2006 Toyota introduced its "all-speed tracking function" for the Lexus LS 460. This radar-assisted system maintained continuous control from speeds of 0 km/h to 100 km/h and is designed to work under stop/go situations such as highway traffic congestion.
2007: BMW introduced full-speed Active Cruise Control Stop-and-Go on the BMW 5 Series (E60).
2008: Lincoln introduced radar adaptive cruise control on the 2009 Lincoln MKS.
2008: SsangYong Motor Company introduced radar Active Cruise Control on the SsangYong Chairman
2008: Volkswagen Passat CC, B6 and Touareg GP. They update current ACC system. Range of speed for ACC 30-210 km/h, but now it support full auto stop (follow to stop). Added Front Assist function to prevent collision and it work separately of ACC. But Front Assist can't brake automaticly, only increases the pressure in the brake system and warns the driver.
2008: Volkswagen Golf 6 introduce ACC with lidar.
2009: Hyundai introduced radar Adaptive cruise control on Hyundai Equus in Korean market.
2009: ACC and CMBS also became available as optional features in the model year the 2010 Acura MDX Mid Model Change (MMC) and the newly introduced model year 2010 Acura ZDX.
2010: Audi world first GPS-guided radar ACC on Audi A8#D4
2010: Volkswagen Passat B7, CC. Next update of ACC and updated Front Assist. Introduced emergency braking, named "City". Car could brake automatically to prevent collision. Speed range for ACC 30-210 km/h with support full auto stop.
2010: Jeep introduced Adaptive Cruise Control on the 2011 Jeep Grand Cherokee
2013: Mercedes introduced DISTRONIC PLUS with Steering Assist (traffic jam assist) on the Mercedes-Benz S-Class (W222)
2013: BMW introduced Active Cruise Control with Traffic Jam Assistant.
2014: Chrysler introduced full speed range radar Adaptive Cruise Control with Stop+ on the 2015 Chrysler 200.
2014: Tesla introduced autopilot feature to Model S cars, enabling semi-autonomous cruise control.
2015: Ford introduced first pickup truck with Adaptive Cruise Control on the 2015 Ford F150
2015: Honda introduced its European CR-V 2015 with predictive cruise control.
The three main categories of ACC are:
Vehicles with Full Speed Range 0MPH are able to bring the car to a full stop to 0 mph and need to be re-activated to continue moving with something like a tap of the gas pedal.
Vehicles with Traffic Jam Assist / Stop & Go auto resume from standstill to creep with stop and go traffic.
Vehicles with Partial cruise control cuts off & turns off below a set minimum speed, requiring driver intervention.
Vehicles with fully automated speed control can respond to traffic signals and non-vehicular on-road activity.
