Since the 1970s, cruise control has gained widespread use and is a standard part of cars today. The idea is simple but effective and makes long drives on the freeway more enjoyable. As always, these kinds of ideas become more advanced over time, and now we have adaptive cruise control, or ACC.

Using radars mounted on the front of the car, the computer can maintain a set distance behind the vehicles in front of you. This way, if the car ahead starts slowing down without you noticing, the computer can see the change in speed and prevent you from getting too close. These radars are also used for pre-crash systems that help slow the car down in the event of something moving in front of the vehicle suddenly.

What the ACC light means

Adaptive cruise control is still used in the same way as regular cruise control. Once you turn on the cruise control mode and get your vehicle up to a particular speed, the car will maintain that speed for you.

Once engaged, the adaptive cruise control will allow you to choose a set distance from cars ahead of you. If the computer sees the gap closing ahead of you, it will apply the brakes to slow your vehicle down and will warn you with an audible chime, flashing lights, or a combination of the two. The brakes won’t be used at full power so you should be ready to step on the brakes if needed. As long as the difference in speed isn’t too great, the system will slow your vehicle down and bring it back up to speed if the gap starts increasing.

Is it safe to drive when the ACC light on?

This system was made to help drivers maintain a safe distance from vehicles ahead of them. If the vehicle continually adjusts the speed while you’re driving, you should consider turning the cruise control off.

Maintaining the adaptive cruise control is important because it is used alongside other safety systems to keep you out of harm's way. Dirt and debris can prevent the adaptive cruise control sensors from working properly so keep the car clean to avoid experiencing any issues. If your car’s adaptive cruise control isn’t working properly, our certified technicians are always available to help you diagnose any problems with it.

This article originally appeared on YourMechanic.com as What Does the Adaptive Cruise Control Warning Light Mean? and was authored by Spencer Cates.


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