(Volvo Cars of North America)

What Is Adaptive Cruise Control?

Cruise control is one of the most successful developments in automotive history. Once considered a luxury feature, now you can hardly find a car on the road without it. But over the 50-plus years since cruise control was introduced to the retail market, it has maintained a singular frustration: You can’t use it in traffic.

You know how it works. You reach your desired speed on the highway, set the cruise, and you think you’re good. Then you come up on some slower traffic, tap the brake pedal, and the cruise needs to be set all over again. Sure, there’s the “resume” feature on most cruise control switches now, and that tells the car to pick up where it left off before the braking, but you’re still having to do it yourself. That’s probably not worth it if traffic is heavy. You’ll find yourself constantly trying to set and re-set the cruise to adapt to the flow of traffic, before finally giving in and going with the original cruise control mechanism: Your foot.

Well, what if your car could use radar to find out how close it was to the cars around it, then automatically adjust the throttle to seamlessly blend into traffic with no input from the driver?

That is adaptive cruise control.

How Does Adaptive Cruise Control Work?

Each manufacturer has a slightly different mechanism for achieving this, but broadly speaking, adaptive cruise control systems use lasers or radar to measure their distance from other vehicles. This means the system is self-contained and doesn’t rely on satellites or information shared by other vehicles to make its calculations. Some radar-based systems incorporate warnings and/or automated braking when the sensor senses an impending collision. For these reasons, adaptive cruise control is considered one of the foundational technologies of autonomous driving, and it has probably been around longer than you think. In cars, the technology traces back to 1992, when Mitsubishi offered a Lidar-based detection system on a vehicle it only sold in Japan, though that system was only a warning and made no inputs on behalf of the driver. 

Shoppers interested in adaptive cruise control systems would do well to learn whether the car they’re considering uses laser or radar for its adaptive cruise control system. Laser systems use exposed sensors placed on the front of the vehicle, commonly on the grille or bumper. These systems won’t work in inclement weather, or if the sensors are dirty or clouded over. Radar systems don’t have that woe. The radar sensor is often hidden behind the grille and is impervious to weather. For this reason, radar systems are more common, but both systems are used widely.

In the most technologically advanced vehicles, adaptive cruise control is one in a series of driver-assist systems that work together to allow the vehicle to drive itself. An adaptive cruise control system can’t do that on its own, but it can save you a lot of aggravation on a long drive.