Cruise control and adaptive cruise control explained

Cruise control has become a common feature in modern cars, allowing drivers to maintain a steady speed without using the accelerator pedal. Ideal for long motorway drives, traditional cruise control allows you to set a specific speed, giving your right foot a much-needed break. While this tech has been around since the 1960s, the system has evolved in recent decades. The latest adaptive cruise control (ACC) systems use sensors to monitor the traffic ahead, automatically adjusting your car’s speed to maintain a safe following distance.

Different carmakers have their own versions of these systems – Audi’s ‘Adaptive Cruise’, BMW’s ‘Active Cruise Control’, and Volvo’s ‘Pilot Assist’ are just a few examples – and some are more intelligent than others, even changing lanes and steering autonomously. Some cars are also equipped with ‘Traffic Jam Assist’, which can handle stop-and-start traffic, easing the stress of daily commutes.

Speeding fines UK 2024: how much will I have to pay?

From straightforward speed control to sophisticated, traffic-responsive systems, cruise control technology can help to take some of the stress out of long journeys. Read on to explore how these features work and how to use them.

What is cruise control?

Cruise control is a system that maintains the speed of a car automatically. Using controls found on or behind the steering wheel, the driver can set a desired speed that the car will continue to follow without any use of the accelerator pedal. It’s found in cars with an automatic or manual gearbox, although its functions are usually more limited in the latter. Most electric cars also come with cruise control.

It’s designed to be used on long A-road or motorway journeys, when prolonged use of the accelerator pedal could cause cramp or soreness in the driver’s right foot. Once a speed has been set, the driver can relax their foot and focus on controlling the car’s steering. The first cruise control systems held the throttle open mechanically, but modern systems are computer-controlled. Many cruise control systems will only activate above a certain minimum speed, usually around 25 to 30mph.

What is adaptive cruise control?

Adaptive cruise control (often abbreviated to ACC) is a more advanced cruise control system that uses lasers, cameras or radar mounted in the front bumper to track the speed and position of the vehicle in front. Cars fitted with the system can automatically match the speed of the vehicle in front and maintain a safe distance. Many systems allow the driver to set their preferred distance to the vehicle in front.

If the vehicle ahead slows down, the driver’s car will also slow down without the need to use the brake pedal. If the vehicle ahead speeds up, the driver’s car will only speed up until it reaches the limit set by the driver. However, only systems paired with an autonomous emergency braking (AEB) system will automatically perform an emergency stop if the car ahead comes to a sudden halt. In 2024 AEB was made a legal requirement for all new cars sold in the UK and the EU.

Adaptive cruise control is sometimes referred to as ‘dynamic’ cruise control, while other automakers use their own names; Mercedes calls it ‘Distronic Plus’ and Porsche, ‘Porsche Active Safe’. 

Some vehicles even have ‘Traffic Jam Assist’, an extension of adaptive cruise control that can automatically slow the car to a halt as well as accelerate and brake at low speeds in congestion, reducing driver fatigue. It’s worth noting that after coming to a halt for more than a few seconds, safety requirements mean driver intervention is usually required; squeezing the accelerator should allow Traffic Jam Assist to resume.

How do I use cruise control?

Check your car’s handbook for the location of the cruise control buttons as they differ from vehicle to vehicle. They are often found in an easy-to-access location, such as on the steering wheel or column stalk, to make them quick and safe to use.

The system can be overridden at any time by pressing on the brake pedal, so you should keep your foot close to the brake in case of emergencies. There may be differences in controls between different manufacturers, so always read your car’s handbook first. Some typical cruise control buttons include:

• On/off: This activates the system, but probably won’t hold you at your desired speed. Turning it on will almost always be accompanied by a dashboard light.
• Set: Once the system is switched on, pressing the set button should tell the car to hold the current speed. In most cars this will turn the dashboard indicator green.
• Cancel: This pauses the cruise control, so you have complete control again, without turning cruise control fully off. The cruise control should still remember the speed you chose to cruise at.
• Res or resume: Pressing this will see the car accelerate back up to the speed you chose before hitting the cancel button or pressing the brake pedal. You'll still need to change gears in a manual car if necessary. An automatic gearbox will change gears for you.
• Up and down arrows or ‘+’ and ‘-’: With cruise control activated, use these to increase or decrease the car’s speed. Single presses often increase or decrease the speed in small increments, while holding the same button or stalk changes it in increments of 5mph or even 10mph. Of course, this varies from one model to another.

Cruise control is best used on long stretches of motorway and should be used to maintain a safe speed while the driver pays full attention to their surroundings. Drivers should not treat cruise control like an autonomous driving system, and the driver needs to pay as much attention to the road when using cruise control as they do with regular driving.

What is a speed limiter?

Some cars are fitted with a speed limiter, either alongside cruise control or on its own. As with cruise control, you set the maximum speed you’d like to travel at, but unlike cruise control, you're still required to press down the accelerator. This is ideal for busy speed-limit zones, where you may want to maintain complete control of your speed without exceeding the limit. Squeeze the accelerator, and your car will simply reach your chosen speed and stop accelerating. However, pressing the throttle pedal all the way down will override the system –it’s a fail safe designed to let you accelerate out of trouble if needed. 

What about Intelligent Speed Assistance?

Like Autonomous Emergency Braking (AEB), Intelligent Speed Assistance (ISA) is another mandatory safety feature fitted to every new car sold in the UK and the EU from 2024. Unlike a traditional speed limiter above, the ISA system uses your car’s GPS and traffic sign recognition cameras to determine the road’s speed limit. The ISA system then limits your car to this speed, stopping you from breaking the speed limit.

The system can be overridden in certain situations when the driver pushes hard on the accelerator pedal, and it can be turned off entirely. However, the system is automatically reactivated every time you start the car. From July 7th 2024, it is a legal requirement for every new car sold in the UK to come with the technology, including unsold new cars sitting in dealerships that will need to have the system retrofitted.

Car technology made simple…

• What are brake pads and discs?
• What is autonomous emergency braking?
• What is ESP on a car?
• What is traffic jam assist?
• What are blind spot monitoring systems?
• What is cross traffic alert?
• Euro NCAP: how safe is my car?