Adaptive cruise control (ACC) maintains a set speed like normal cruise control, but uses radar, lidar or cameras to keep a safe following distance from the vehicle ahead — slowing down, and in modern systems stopping and restarting, automatically. It appeared in the mid-1990s in Japan, and Mercedes-Benz introduced one of the first radar-based systems, Distronic, on the 1998 S-Class. Today ACC is common even on affordable cars and underpins more advanced driver-assistance systems.

Timeline

Year Milestone
1958 Conventional cruise control (Chrysler)
1995 Laser-based distance control (Mitsubishi, Japan)
1998 Radar-based Distronic (Mercedes-Benz S-Class)
2000s Radar ACC spreads across luxury brands
2005–06 Stop-and-go ACC
2010s ACC combined with lane centering

How it works

A forward-facing sensor measures the distance and closing speed of the vehicle ahead. If traffic slows, the system reduces throttle and applies the brakes; when the road clears, it accelerates back to the set speed. Drivers choose a following gap.

Stop-and-go

Newer systems can bring the car to a complete stop in traffic and resume automatically after a short stop — valuable on congested roads like the Long Island Expressway or the approaches to the Lincoln Tunnel.

Combined with lane centering

When ACC is combined with steering assistance, the car can maintain speed, distance and lane position — the basis of Level 2 systems like Super Cruise and BlueCruise. Read Super Cruise vs Autopilot vs BlueCruise.

Limitations

ACC may not detect stationary vehicles in all situations, can be affected by heavy rain or snow, and requires the driver to remain attentive. Read the history of cruise control.

In professional hands

For chauffeurs, ACC reduces fatigue on long highway runs, and smooth following distances make the ride calmer for passengers — but the chauffeur remains fully in control. Read how chauffeurs plan routes.