Adaptive Cruise Control (ACC) is an advanced driver-assistance feature that automatically adjusts a vehicle’s speed to maintain a safe following distance from the car ahead.

Unlike traditional cruise control, which keeps a constant speed, ACC uses sensors—such as radar and cameras—to detect traffic conditions and slow down or accelerate as needed, making driving smoother and reducing driver workload.

**Adaptive cruise control-Everything you need to know**

Adaptive Cruise Control (ACC):

Adaptive Cruise Control (ACC) is an advanced driver-assistance system (ADAS) that automatically adjusts a vehicle’s speed to maintain a safe distance from the vehicle ahead.

It enhances conventional cruise control by adding intelligent sensing, automatic braking, and speed adjustment features.

ACC improves comfort, safety, and traffic flow, especially during highway driving.

1. What is Adaptive Cruise Control?

Adaptive Cruise Control is a smart system that:

Maintains a driver-set speed
Monitors traffic ahead
Adjusts speed automatically
Maintains a preset following distance
Can brake or accelerate on its own

In modern cars, ACC is often integrated with:

Lane Keeping Assist
Automatic Emergency Braking
Traffic Jam Assist

2. Working Principle of ACC (Step-by-Step)

ACC uses a combination of radar, camera, and sometimes lidar sensors to detect what is happening in front of the vehicle.

Also read: How to set adaptive cruise control in car?

Step 1: Driver sets speed and following distance

Example: 90 km/h with medium gap.

Step 2: Sensors continuously scan the road

ACC identifies:

Vehicle ahead
Distance to the vehicle
Relative speed
Lane markings (via cameras)

Step 3: System calculates required speed

If the road is clear → vehicle maintains the set speed.
If a slower vehicle is ahead → ACC reduces speed.

Step 4: Automatic speed adjustment

ACC slows down using:

Throttle reduction
Gear downshifts
Automatic braking

Step 5: Automatic acceleration

When the lane clears, ACC accelerates back to the preset speed.

Step 6: Safe distance control

ACC keeps a constant gap using dynamic distance measurement algorithms.

3. Sensors Used in Adaptive Cruise Control

A) Radar Sensors (Primary)

Mounted in the front grille or bumper
Detects distance and relative speed
Performs well in low light

B) Camera Sensors

Located near the windshield
Identifies vehicles, lane markers, signs
Works with radar for better accuracy

C) Lidar Sensors

Used in high-end systems
Extremely accurate distance measurement
Sensitive to weather conditions

D) Ultrasonic Sensors

Helpful at low speeds and during stop-and-go traffic

4. Types of Adaptive Cruise Control

1. Basic ACC

Works only at higher speeds
Disengages at low speeds
Suitable for highways

2. Stop-and-Go ACC

Works from 0 km/h
Handles heavy traffic
Can bring the car to a full stop and resume automatically

3. Predictive/Navigation-based ACC

Uses:

GPS data
Map information
Traffic predictions

Can slow down for:

Curves
Tunnels
Speed limits

4. Sensor Fusion ACC

Combines radar + camera + lidar for high accuracy.

5. Features of Adaptive Cruise Control

Automatic braking and acceleration
Maintaining safe following distance
Stop-and-go operation
Traffic jam handling
Smooth acceleration and braking
Collision warnings
Integration with AEB and Lane Assist

6. Advantages of Adaptive Cruise Control

1. Increases Safety

Reduces rear-end collisions
Keeps safe distance automatically

2. Reduces Driver Fatigue

Especially helpful during:

Long highway drives
Stop-and-go traffic

3. Improves Comfort

Smooth speed control and reduced manual braking.

4. Enhances Fuel Efficiency

Maintains steady speeds and avoids sudden braking.

5. Works Well with Other ADAS Systems

Forms a foundation for semi-autonomous driving.

7. Disadvantages of Adaptive Cruise Control

Performance affected in heavy rain, fog, or snow

High repair and calibration costs

sudden disengagement possible

Occasional false braking

Dependent on sensor cleanliness and accuracy

May misinterpret stationary objects

Drivers may become over-reliant

ACC is not a replacement for full driver attention.

8. Limitations of ACC

Difficulty detecting stationary vehicles
Limited performance on sharp curves
Struggles with motorcycles or small objects
Sensor blockage reduces effectiveness
Not ideal for slippery roads without traction control

9. Applications of Adaptive Cruise Control

Highway driving

Smooth and consistent speed.

City traffic (Stop-and-Go ACC)

Handles crawling traffic.

Commercial vehicles

Used in trucks and buses for safety and fuel savings.

Semi-autonomous systems

Forms the basis for:

Lane centering
Traffic Jam Assist
Highway Assist

10. Summary

Adaptive Cruise Control is an advanced system that maintains a set speed and automatically adjusts to traffic using radar/cameras.
It can brake, accelerate, and keep a safe distance.
ACC enhances comfort and safety but has limitations in bad weather and complex traffic scenarios.