Technology & Telematics · Driver Training VideoAdaptive Cruise Control

Adaptive cruise control, or ACC, uses forward-facing radar and camera to hold a set gap behind the vehicle ahead. Set your speed, and the system slows down when traffic ahead slows, then speeds back up when the lane clears. It sounds like an autopilot. It is not one.

ACC is a driver assistance system. It assists. It does not drive the truck. Your hands stay on the wheel, your foot stays near the brake, and your eyes stay on the road the entire time it's engaged.

Here's where drivers get hurt

ACC reads what's directly in front of you through radar and camera, and it struggles with the same things your eyes struggle with — heavy rain, snow, fog, or a dirty, iced-over sensor.

The following-distance rule does not go away because a computer is holding the gap. One second per ten feet of vehicle length, plus one more second above 40 miles per hour, is still the standard, and most ACC systems let you choose a following gap.

Your company standard: ACC stays on for open highway driving in clear conditions, set to the maximum available gap. Turn it off, and physically disengage, on wet or icy pavement, in fog, in work zones, in heavy or stop-and-go traffic, and on any ramp or curve.

Treat this system the way you'd treat a new driver riding with you — helpful, but not something you hand the wheel to. Use it to cut fatigue on long, clear stretches. Do not use it to check out.