Guide to Adaptive Cruise Control

How this convenience feature works to reduce your stress on long drives

Illustration of a car safety system Photo Illustration: John Ritter

Adaptive cruise control (ACC) is like traditional cruise control, but smarter. ACC systems allow you to set a desired speed until your vehicle encounters slower-moving traffic. Then it will brake to maintain a set distance from the car ahead. Once the traffic starts moving again or if there is no longer a car in the lane ahead, ACC will accelerate to resume the previous set speed. Although ACC systems may take some getting used to, our survey respondents told us they appreciated the stress relief the feature brings.

“I use the feature mostly on the freeway and in stop-and-go traffic. I find it reduces tension and fatigue,” wrote a 2020 Subaru Outback owner. A 2018 Audi Q5 driver agreed. “It is so nice to just set it and let the car worry about the traffic,” they told CR.

The systems use lasers, radar, cameras, or a combination of those. If traffic slows to a stop, most ACC systems will bring the car to a complete stop, then bring it back up to speed when traffic gets going again. Others work only within certain speeds and/or might not start to accelerate automatically.

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Adaptive cruise control (ACC): Cruise control that also assists with acceleration and/or braking to maintain a driver-selected gap to the vehicle in front. Some systems can come to a stop and continue while others cannot. If the car comes to a full stop, you may have to press the accelerator or a button on the steering wheel to start moving again.

Not all systems work at low speeds, so drivers who plan to use ACC in slow traffic should check the limitations of any system they plan to buy. These particular systems will often have the words “traffic jam” or “stop and go” in their name.

These features are usually activated using a button on the steering wheel with the image of a car next to a speedometer with an arrow pointing at it. A conventional cruise control system does not automatically keep a set distance away from the car in front, and it is indicated by a similar logo without the car next to the speedometer. A tip to know if your car has adaptive cruise control or regular cruise control is to look for the “gap distance” button, which usually shows a symbol of a car with horizontal distance bars in front. This button will determine how much space your car leaves between its front bumper and the rear of the car it is following.

In our most recent survey, we asked CR members to rate their experiences with the advanced safety and driver assistance systems on their model-year 2017 to 2022 cars. Respondents answered questions about their satisfaction with the systems. The survey covered about 47,000 vehicles. Most respondents told us they were “very satisfied” with ACC. Satisfaction was higher for older drivers.

Adaptive Cruise Control (ACC)

OVERALL SATISFACTION

63%

What to Look For in an Adaptive Cruise Control System

Every ACC system works slightly differently, says Kelly Funkhouser, manager for vehicle technology at CR. Some do a better job than others at recognizing merging traffic and automatically apply the brakes, while others wait too long to slow your car, requiring the driver to take control—especially when a vehicle in front of you cuts you off with a close merge.

“Most ACC systems can only be set to speeds above 20 mph but will slow the vehicle to speeds below that in stop-and-go traffic,” she says. “There are a few systems out there that don’t bring the car all the way to a stop but instead just shut off at low speeds. That can be dangerous when you’re traveling behind another slowing vehicle.” She recommends reading the automaker’s website closely and learning about the speed ranges before using ACC while on your test drive.

ACC is meant for convenience, not as a replacement for an alert driver, Funkhouser says. So don’t use adaptive cruise control as an excuse to get distracted. “Just because the car is controlling your speed doesn’t mean that you can check out,” she says. “These systems do not do well at detecting or slowing for vehicles ahead if you approach them at a high rate of speed. The driver should always be monitoring the surrounding traffic and looking ahead for potential hazards.”


Head shot photo of CRO Cars CIA editor Keith Barry

Keith Barry

Despite my love for quirky, old European sedans like the Renault Medallion, it's my passion to help others find a safe, reliable car that still puts a smile on their face—even if they're stuck in traffic. When I'm not behind the wheel or the keyboard, you can find me exploring a new city on foot or planning my next trip.