Adaptive Cruise Control: How Does It Work?

Quick Facts About Adaptive Cruise Control

When paired with lane-centering or lane-keep assist, adaptive cruise control is essentially Level 2 autonomy.
Adaptive cruise control allows the driver to relax a bit because it automatically maintains a safe distance from traffic ahead.
Some carmakers have their own unique name for adaptive cruise control, like Nissan’s Intelligent Cruise Control.

When carmakers pitched cruise control to the American public more than half a century ago, they framed it as a way to maintain a safe, consistent speed on the highway and a path to conserving fuel. Although the fuel savings were minimal, both claims were accurate.

Simple to use, all you need to do is turn on the system in your vehicle, reach your desired cruising speed, and set it. The system then assumes control of the accelerator, maintaining the set speed until the driver engages the brake. Easy peasy.

Automotive engineers tweaked around the edges of cruise control for the next 35 years. However, cruise control didn’t evolve much beyond the first system that found its way into the 1958 Chrysler Imperial.

By the early 1990s, Japanese carmakers were adding a form of forward collision warning to their cruise control, but it was still up to the driver to react and apply the brakes. Not until Mercedes-Benz developed its Distronic cruise control did cruise control with self-braking make its first public appearance. Mercedes originally featured it on its 1999 S-Class.

In essence, not only did the 1999 S-Class introduce adaptive cruise control (ACC), but it also set the cornerstone of the foundation for self-driving vehicles.

Standard cruise control is still the more prolific speed control found on cars currently on the highway, but adaptive cruise control has been gaining ground. More and more car models provide it as standard or as an available option. But what exactly is adaptive cruise control, and how does it work? Let’s see.

What Is Adaptive Cruise Control?
Is Adaptive Cruise Control Worth It?
How Does Adaptive Cruise Control Work?
Benefits and Limitations of Adaptive Cruise Control
What Is the Difference Between Adaptive Cruise Control and Self-Driving?
What Carmakers Call Their Adaptive Cruise Control Systems
Can I Add Adaptive Cruise Control to My Car?
Conclusion

What Is Adaptive Cruise Control?

Adaptive cruise control systems vary in sophistication from carmaker to carmaker and sometimes even model to model. They also vary in name. For example, Genesis calls it Smart Cruise Control, while BMW identifies it as Distance Control. In a nutshell, the feature holds a preset speed while maintaining a safe following distance from the traffic in front of it. ACC essentially makes commuting and road trips so much easier.

Depending on the system, here’s what else the feature can do:

Set the distance. Most systems allow you to set the following distance within parameters like one, two, or three cars.
Stop the vehicle in traffic. Some ACC systems will bring the car to a complete stop if the traffic before it stops. However, they won’t self-accelerate when traffic begins moving again.
Stop and start in traffic. Some systems will bring the vehicle to a complete stop and then automatically accelerate as the flow of traffic resumes.
Work at low speeds in city traffic. Other systems use an add-on called traffic-jam assist designed to fully function in low-speed or stop-and-go traffic found on city streets or logjammed highways.
Slow down at curves. Moreover, there are ACC systems capable of working with your vehicle’s GPS mapping to anticipate approaching curves, slowing the car going into the curve if it determines the preset speed is too high.
Adjust to speed-limit variations. Some systems working in conjunction with traffic-sign recognition or GPS will adjust the speed according to speed-limit variations.
Appear in head-up display. The ACC will show up in your view for vehicles equipped with head-up display.

Is Adaptive Cruise Control Worth It?

We say yes. This is particularly true if you do a lot of highway driving. Moreover, the more sophisticated systems with full stop and start or a low-speed traffic-jam feature work great for city driving. However, typically, adaptive cruise control gets included in a trim level or some sort of optional driver-assistance package on new cars. You will rarely find it listed as a stand-alone option. This means, of course, to get adaptive cruise control, you may wind up paying for a lot more than just adaptive cruise control.

For example, the Chevy Trailblazer LT ($25,695 with destination fee) offers its system as an option but makes the buyer pony up for its Driver Confidence Package ($395) to add its optional Adaptive Cruise Control Package with rear cross-traffic alert, blind-spot monitoring, and rear parking sensors for a total outlay of an extra $1,495. Even on the top-of-the-line RS trim ($29,095), adaptive cruise control is lumped into a huge package with an upgraded Bose audio system, wireless phone charging, an auto-dimming rearview mirror, and more for a $2,585 premium.

We’ve picked a few models at random to illustrate the availability and cost of having adaptive cruise control. The trim levels listed represent the lowest trim level on which ACC is standard or optional. The prices include the factory-to-dealer delivery charge.

Make, Model, and Trim	Standard or Optional	Adaptive Cruise Control Extra Cost
Honda Civic LX	Standard	$0
Toyota RAV4 LE	Standard	$0
Kia Sportage SX	Standard	$0
Ford Escape Active	Optional	$4,370
Mercedes C-Class	Optional	$1,950
Subaru Outback	Standard	$0
Hyundai Tucson SE	Standard	$0
Buick Envision Preferred	Standard	$0
Lexus RX 350	Standard	$0
Mazda CX-30 2.5 S	Standard	$0

How Does Adaptive Cruise Control Work?

Think of adaptive cruise control as cruise control with a Ph.D. It can use radar, laser, binocular computer vision systems, a forward-aimed camera, or some combination of these technologies to track the traffic ahead of your vehicle. It senses when that traffic flow slows or stops, reacting to maintain the preset following distance.

As stated earlier, some systems will bring your vehicle to a complete stop to match traffic flow. Even more intelligent systems can then accelerate as the traffic flow resumes. These are called assisting, predictive, and multi-sensor systems.

Benefits and Limitations of Adaptive Cruise Control

Warming up to adaptive cruise control took some time for Kelley Blue Book reviewers. Early systems didn’t allow for presetting the maintained following distance. Consequently, a vehicle six or seven car lengths ahead of you moving into your lane became almost an airbag-deploying event. However, as adaptive cruise control systems evolved and improved, we became more accustomed to them. We now look at regular cruise control as, well, barbaric.

Pros

Reducing driver stress: No question, the number one benefit of adaptive cruise control is allowing the driver to relax a bit. The system assumes the responsibility of slowing and accelerating to adjust to traffic flow. This doesn’t mean the driver gives up control, but the system assumes the workload of keeping pace with the traffic flow.
Stop and go: With more intelligent systems, adaptive cruise control assumes complete control of braking and accelerating. In other words, it can bring the vehicle to a full stop and then accelerate as the flow of traffic resumes. Some systems will disengage after stopping and leave it to the driver to push the “Resume” button or tap the accelerator to get moving again. However, more sophisticated systems will accelerate themselves from a complete stop.
Improved Traffic Flow: Adaptive cruise control allows for a smoother driving experience without abrupt braking and undisciplined acceleration.
Enhanced Safety: Although rarely cited as a benefit of adaptive cruise control, removing the human factor from initiating braking and acceleration in crowded stop-and-go traffic can reduce the rate of fender benders and even fatalities. A recent study out of China in the Journal of Safety Research came to this very conclusion.
Easy to use: For drivers not able (or willing) to read a car manual before setting out on the highway, you can fiddle with the adaptive cruise control system and pick it up with a little practice.

Cons

Not autonomous: Regardless of an adaptive cruise control system’s sophistication, the driver must stay engaged. Adaptive cruise control can’t read the minds of vehicles around it. It only reacts to what other cars do. Anticipating the actions of other drivers remains your responsibility.
No stop and go: Adaptive cruise control systems that don’t offer a full stop will slow the vehicle but require the driver to bring it to a full stop when the flow of traffic stops. Even if an adaptive cruise control system does bring the vehicle to a full stop, it may still require the driver to re-engage the system to get back underway.
No lane change: An adaptive cruise control system itself can’t change lanes automatically to maintain the preset speed. Therefore, if you’re not paying attention as the driver, you may find your vehicle is going several miles an hour below the set speed. This is because your vehicle has gradually pulled up behind a slow-moving car, and you have steadily slowed to its pace. This is another reason you should stay engaged.

What Is the Difference Between Adaptive Cruise Control and Self-Driving?

There continues to be plenty of confusion about self-driving or autonomous systems, what they are, and how they operate. We’ll get to that next. However, the major difference between adaptive cruise control and a self-driving system is that adaptive cruise control is simply a component of a driverless system. That is to say, adaptive cruise control provides automatic braking and acceleration in a self-driving system that also includes steering and sometimes automatic lane changing.

What Is the Difference Between Level 2 and Level 3 Autonomous Driving?

We won’t take you through all levels of driving automation. They begin with no automation and wrap up with full automation, including vehicles without pedals or steering wheels. See the chart above from SAE International.

What we will contrast are Level 2 and Level 3. Spoiler alert: The difference is significant.

Level 2 — To qualify as Level 2, a vehicle must have at least two driver-assistance technologies. This typically includes adaptive cruise control and another technology like lane-centering assist or lane-keeping assist. With these technologies, the vehicle can steer, accelerate, and brake on its own in certain conditions. Level 2 still requires the driver’s hands on the wheel and eyes on the road. Despite much hoopla to the contrary, Level 2 is the current state of automation.

Level 3 — If Level 2 is partial self-driving, Level 3 is conditional full automation. A Level 3 self-driving system uses a wide spectrum of driver-assistance features and artificial intelligence (AI). These technologies collude to react to and make decisions about the vehicle’s ever-changing situations. In a Level 3 vehicle, the driver can completely surrender control of the vehicle’s operation on specific roads. The driver must be prepared to resume control in case of an emergency, but otherwise doesn’t have command of the car. That is, the driver’s hands can be off the steering wheel and their attention elsewhere.

Although the state of autonomous driving today is Level 2, a few carmakers are on the precipice of Level 3. For example, Tesla’s Enhanced Autopilot, Ford’s BlueCruise, and General Motors’ Super Cruise bring the potential for Level 3. A few over-the-air software tweaks will turn the potential into reality. However, like a stood-up date who is all dressed up with nowhere to go, you will not find Level 3-designated highways as of yet.

The Big But

However, one carmaker, Mercedes-Benz, has its Drive Pilot, a Level 3 system approved for a few limited roadways in California and Nevada. Currently, Mercedes only offers Drive Pilot capability on its EQS and S-Class.

What Carmakers Call Their Adaptive Cruise Control Systems

Is anyone surprised that carmakers can’t seem to agree on a single term for adaptive cruise control? How about “adaptive cruise control?” We can sort of forgive Mercedes for its Distronic cruise control. It was first, after all. However, can someone define “distronic?” Anyone, anyone? Nope, because it’s a made-up word. So, why not use adaptive cruise control?

Mercedes isn’t alone. Many carmakers use unique terms for adaptive cruise control. Some call it adaptive cruise control as the root, then tack something onto it based on enhanced capabilities. For example, Audi used Adaptive Cruise Control until its system is mated with traffic-jam assist and lane-centering assist. Then Audi refers to it as Adaptive Cruise Assist.

Here’s a rundown of the terms the various carmakers use for adaptive cruise control, even those that simply call it adaptive cruise control.

Acura — Adaptive Cruise Control with Low-Speed Follow
Alfa Romeo — Intelligent Speed Assist
Aston Martin — Adaptive Cruise Control
Audi — Adaptive Cruise Assist
Bentley — Adaptive Cruise Control
BMW — Distance Control
Buick — Adaptive Cruise Control
Cadillac — Adaptive Cruise Control
Chevrolet — Adaptive Cruise Control
Chrysler — Adaptive Cruise Control with Stop and Go
Dodge — Adaptive Cruise Control
Ford — Adaptive Cruise Control with Stop-and-Go
GMC — Adaptive Cruise Control
Genesis — Smart Cruise Control
Honda — Adaptive Cruise Control
Hyundai — Smart Cruise Control
Infiniti — Intelligent Cruise Control
Jaguar — Adaptive Cruise Control
Jeep — Adaptive Cruise Control
Kia — Smart Cruise Control
Land Rover — Adaptive Cruise Control with Stop and Go
Lexus — Dynamic Radar Cruise Control
Lincoln — Intelligent Adaptive Cruise
Lucid — Adaptive Cruise Control with Speed Limit Assist
Maserati — Adaptive Cruise Control with Stop and Go
Mazda — Mazda Radar Cruise Control with Stop and Go
Mercedes-Benz — Distronic Plus
Mini — Dynamic Cruise Control
Mitsubishi — Adaptive Cruise Control
Nissan — Intelligent Cruise Control
Polestar — Adaptive Cruise Control
Porsche — Adaptive Cruise Control
Ram — Adaptive Cruise Control with Stop, Go and Hold
Rivian — Adaptive Cruise Control
Rolls-Royce — Active Cruise Control
Subaru — Adaptive Cruise Control
Tesla — Traffic-Aware Cruise Control
Toyota — Dynamic Radar Cruise Control
Volkswagen — Adaptive Cruise Control
Volvo — Adaptive Cruise Control

Can I Add Adaptive Cruise Control to My Car?

Yes, you will find aftermarket adaptive cruise control kits available. Depending on the features, they range in cost from $250 to nearly $4,000. That’s just the cost of the kits. The installation will add even more. For most involved electric-system installations, it’s best to get them done by a dealership or certified mechanic. We believe that’s the case with an adaptive cruise control system. Installation cost depends on the sophistication of the system and the vehicle model.

Conclusion

With many carmakers offering adaptive cruise control as standard equipment on their base trim level, nearly every driver who wants it can get it without breaking the bank. We particularly like it for reducing the stress in stop-and-go traffic.
RELATED: Ford Expands BlueCruise Hands-Free Options