What Is Adaptive Cruise Control?

Cruise control is one of the original driver assistance systems. Early versions of it—which held the throttle in a fixed position—date back to the early 1900s. Cruise control as we know it today got its real start commercially in 1958 with Chrysler’s “dial-a-speed” feature called Auto-Pilot. (There was literally a knob on the dashboard.) Cadillac took that idea, gave it a more familiar format (with buttons similar to the ones we have today), and coined the term that we still use.

That original form of cruise control was primarily about reducing driver fatigue: Drivers wanted to take a break from keeping their foot on the gas pedal for long stretches. Cruise control made those extended drives a bit less physically taxing.

Adaptive cruise control (ACC), which was initially developed in the 1990s, was a major advance. Rather than setting a speed and sticking with it, adaptive cruise control gauges the distance between your car and the one you’re following and adjusts your speed to maintain a safe distance. ACC is now commonplace. According to one market analysis, installation rates tripled from 2017 to 2023; more than 60% of 2023 model-year vehicles have it.

How does adaptive cruise control work?

While it may sound sophisticated, adaptive cruise control isn’t that complex technologically. Today’s ACC relies on sensory devices at the front of the vehicle, including basic radar sensors, video cameras, and lasers, depending on the system. An onboard computer uses data from those sensors to calculate the distance to the car ahead and its speed relative to yours. When your car gets closer than the system deems safe, ACC decelerates (by slowing down the engine or engaging the brakes) until you match the speed of the car ahead.

This simplicity means adaptive cruise control can be adopted broadly in a wide range of vehicles. Soon, adaptive cruise control is likely to be available in most new cars, at least as an option, says Greg Brannon, director of automotive engineering for AAA. That’s in large part because adaptive cruise control uses the same sensors as automatic emergency braking (AEB) systems, which have been widely adopted in cars produced since 2022. (Starting in 2029, all passenger cars and light trucks sold in the United States will be required to have AEB standard.) “Since manufacturers are including AEB for free, they figure they might as well include ACC that they can charge for,” Brannon says.

What are the pros and cons of adaptive cruise control?

“Adaptive cruise control is one of the most effective driver assistance technologies we have,” says Brannon. “I do think it’s changing driving habits.”

One study found that vehicles equipped with both AEB and forward collision warning had a nearly 50% reduction in rear-end collisions compared to those without these features. While ACC on its own may not offer that big of a safety benefit, Brannon believes it probably has the additional benefit of causing drivers to brake and change lanes less frequently. “It definitely takes some of the stress, anxiety, and even anger out of driving,” he says.

But while ACC can assist drivers, it can’t drive the car for them. And its reliance on radar and cameras saddles it with some unavoidable limitations. ACC can be dangerous to use in poor visibility caused by rain, snow, or fog, which can interfere with sensors. That’s one reason AAA specifically suggests avoiding cruise control when conditions are wet.

ACC also doesn’t work well on sharp curves. Many drivers find that their adaptive cruise control systems often get confused when the car they’re following pulls to one side to turn. The combination of ACC and adaptive lane keeping systems may also blindly follow the driver in front, even if they’re driving badly, Brannon says.

While logic suggests that ACC should improve traffic conditions, some studies have found that it can actually do the opposite: It may cause unnecessary traffic jams if multiple cars using the technology on the same stretch of road hit the brakes at the same time.

What’s next for cruise control?

Brannon notes that few advanced driver assistance technologies are as well-tested and as reliable as adaptive cruise control. The one change he foresees in the near future is that ACC will likely be increasingly combined with related technologies, such as lane-keeping assistance and traffic jam assistance.

Until then, Brannon’s best advice for getting the most out of the technology is simply to use it in situations where you feel comfortable with it, such as moderate traffic conditions at highway speeds. “The more you use it, the more comfortable you will likely get,” he says. “But remember that the driver is always responsible for maintaining control of the vehicle.”