Adaptive Cruise Control—What Is It and How Does It Work?

Cruise control--a type of vehicle function that has been around since the '60s, allows a driver to set the speed that the car will stay in with the push of a button. Once the button is pushed and the speed is set, the driver no longer needs to step on the accelerator pedal. A useful function as it is, but now cruise control has evolved, adding the ability to adjust vehicle speed based on the vehicle in front. This is what's called as adaptive (or active) cruise control.

The basics of adaptive cruise control

Adaptive cruise control (ACC) works similarly to regular cruise control. The 'adaptive' part means that your car will 'adapt' or 'react' to the speed of the car in front of you. If the car in front of you slows down, then your car will slow down as well. If it speeds up, then so do you.

ACC's ability to adjust your vehicle speed is made possible by a radar, lidar, or camera sensing system (depending on the vehicle manufacturer's chosen technology) in the front of the car. The sensor adjusts the speed according to the distance in seconds that you set between you and the other car. Normally, you can set your car to stay two, three, or four seconds behind the car you're following.

ACC is now almost always bundled with other safety systems such as lane keeping, blind spot monitoring, and collision warning that alerts you of a possible impact and then applies the brakes for you to protect you from accidents. These are often marketed as a packaged safety system depending on the manufacturer of the vehicle.

How Useful is ACC?

If you frequently face stop-and-go traffic in your daily commute, then driving a car with ACC can be extremely helpful. In such traffic conditions, vehicle speeds are constantly changing, and can come to a full stop without much warning. If a driver is not paying attention for even a moment, an accident is likely to occur. Fatigue, boredom, and distractions only serve to increase the risk. Having ACC is like having someone driving the car for you. That's why it’s a crucial piece of tech in self-driving cars in the near future.

Do all ACC systems work the same?

No; different ACCs will vary from model to model. Some only work between specific speeds (for instance, between 50 kph and 150 kph), while some will even work at high speeds in excess of 200 kph! Some require the assistance of the accelerator to speed up back to the preset speed.

How reliable is modern ACC technology?

Despite its usefulness, you should never fully rely on an ACC to save you from a possible accident. Adverse weather conditions, as well as other unforeseen issues, can hamper their capabilities. If your car has ACC, it is important to understand its limitations, and make sure you only use it as a secondary aid to your own driving. ACC is far from a set-and-forget tool, and you must remain focused at all times to what's happening on the road.