What is cruise control in a car? Meaning and how does it work?

What is cruise control in a car?

It is a system that accurately maintains the speed set by the driver without any external intervention. It automatically controls the speed of a car and only allows the vehicle to hit a speed set by the driver. It does not allow the car to cross that speed limit. This feature has become common among modern cars. You can even find this feature in the top-spec variants of some of the affordable hatchbacks and sedans.

How does the cruise control system work?

Cruise control in a car replicates the inputs of a driver to control the vehicle’s speed. But instead of pressing the accelerator pedal, it uses a different mechanism to maintain a constant cruising speed.

Initially, the system used a cable to control the accelerator (throttle valve). You can find these mechanisms in older cars. It adjusted the vehicle's speed by engaging the throttle with the help of an actuator that is controlled by a cable. The throttle valve is responsible for the power and speed generated by the engine. So, depending on the speed set by the driver, the system automatically adjusted the throttle position.

But with the advent of technology in the automotive industry, the cruise control system in modern cars entirely relies on electronics. Instead of a cable, the system now communicates with the throttle via various sensors connected to a computer (ECU - Electronic Control Unit). So, when you set a speed, the ECU calculates the throttle position and engages the throttle wirelessly.

The system constantly maintains the speed set by you (driver) irrespective of road conditions. For example, if there’s an incline ahead, cruise control adjusts the throttle accordingly to maintain the same speed.

How to use cruise control?

Before engaging the cruise control in a car, remember that the system is not intended to be used in adverse weather conditions. For example, you may refrain from driving the car at cruising speeds when it’s raining heavily. The low visibility and unpredictable road conditions make it unsafe to drive at such speeds. So, always be mindful of the weather condition and your surroundings before engaging the system.

Here are the steps to use cruise control.

Step 1 - Before activating cruise control, build up speed by accelerating the car. However, do not cross the speed limit of that particular road/highway.

Step 2 - Once your car reaches the desired speed, activate cruise control. Generally, the system activation button will be on the steering wheel. However, locating the exact button when the vehicle is parked is better to avoid any distractions while driving.

Step 3 - Next, you can take your foot off the accelerator pedal. If you have set the cruise control correctly, the car should maintain the cruising speed.

Step 4 - Keep your eyes on the road as it is very easy to get distracted when the car is accelerating automatically.

Step 5 - If you wish to accelerate when the cruise control is engaged, you can press the ‘+’ button on the steering wheel to briefly engage the accelerator pedal.

Step 6 - To decelerate, press the ‘-’ button on the steering wheel. You can also tap on the brake pedal. However, as a safety precaution, almost all cars will deactivate the cruise control as soon as you press the brake pedal.

The buttons to activate cruise control or accelerate/decelerate may vary from one car to another. So, do check the owner’s manual before fiddling around with the system. It’s better if you are familiar with the controls before driving the vehicle, as it will avoid unnecessary distractions.

How to install cruise control in a car?

Can you install cruise control in a car? The answer is both yes and no. You may install an aftermarket kit if it’s an old car that does not rely on electronics to control all the engine-related functions. But installing such a kit becomes almost impossible in modern cars due to the complex electronics.

It is a complex process to install the system in new cars as you have to fiddle with electronics, and it also requires the fitment of hardware. So, it can only be done during the time of car manufacturing. Moreover, if you try installing an aftermarket kit, you may void the warranty offered by the OEM (Original Equipment Manufacturer). On top of that, it is not recommended to go for an aftermarket cruise control kit as it may compromise safety.

Newly launched cars are equipped with cruise control except for a few entry-level models. So, instead of investing in retrofitting a system, it's better and safer to spend that money on buying a car with a built-in system.

Adaptive cruise control

The new technology also allows the system to automatically adjust the car's speed depending on the speed of the vehicle ahead. This feature is known as adaptive cruise control. It ensures that the car maintains a safe distance from the vehicle ahead despite the constant change in speed of the vehicle moving ahead. It is instrumental in highways or during rush hour traffic and reduces driver fatigue.

It is also a level 1 autonomous driving system. The system uses radar sensors to calculate the speed and distance of the car ahead. For instance, if the vehicle in front of you slows down/speeds up, a car with adaptive cruise control will reduce speed/accelerate automatically without any external inputs.

You can find this feature in premium cars. But gradually, it is trickling down to not so expensive cars as well. Adaptive cruise control is a part of an advanced driver assistance system.

Pros and cons of cruise control

Cruise control makes driving easy and convenient, and at the same time, it also takes care of safety. But like every other feature, it has its own set of advantages and disadvantages, which are elaborated in the following section.

Below are some of the pros of the cruise control system.

• Reduces driver fatigue: The primary role of cruise control is to maintain a constant speed without you having to step on the accelerator pedal. That means you can rest your right foot and can stay relaxed. It is helpful when you drive long distances on highways where you need to maintain a constant speed for long durations.

• Improves fuel economy: When maintaining a constant speed, the engine will not get stressed as it need not change the intensity of operation. To put it in a simple way, when the engine runs at constant RPMs (Revolutions Per Minute), it consumes less fuel. Hence, when driving long distances on highways, the cruise control system can improve fuel economy.

• Helps to drive within the speed limit: You may drive at normal speed on busy urban roads. But when you hit the wide and smooth highways, you may end up crossing the speed limit. You may not even realise that you have crossed the speed limit until you glance at the speedometer. Cruise control can help you in this regard as you can easily set a speed limit and let the system do the work. The system will not allow the car to go over the speed set by you.

• Increase/decrease speed with a click of a button: Typically, you use the accelerator and brake pedal to increase/decrease the speed of your car. But when the cruise control is engaged, you can even use the buttons to do the job for you. However, ensure that you are familiar with the functions of the buttons, as it may feel unnatural in the beginning. It is best to practice using the buttons in a safe environment before using them on public roads.

• Works well with automatic cars: Cruise control works best with automatic cars as you need not worry about changing gears. The ECU or the onboard computer shifts the gears automatically when there is a change in speed and works well when cruising automatically. It means you only need to focus on steering the vehicle.

As mentioned earlier, cruise control also has some cons, which are listed below.

• Limited use on Indian roads: Cruise control is suited for wide and long highways where drivers follow the rules. Although India has some excellent highways, many drivers may disregard rules which creates an unpredictable environment. Also, cattle, dogs and other animals may venture into public roads and make the situation even more tricky. Hence, it may be challenging to cruise at high-speeds.

• Hampers reaction time: As mentioned above, the roads in India are unpredictable. You may have to perform emergency braking to avoid any obstacles on the road. When driving with manual controls, your right foot will be on the accelerator pedal, and it is easy to move your foot to step on the brake pedal in an emergency. But, when using cruise control, your right foot will be resting on the floor of the car, and it may take a bit more time to reach the brake pedal. This difference in reaction time may be the difference between you avoiding an obstacle or crashing into it.

• Can induce drowsiness: If you use cruise control for long durations, you may end up feeling drowsy. Since the car is accelerating at a constant speed, your alertness level may drop in the long run. Hence, it is recommended that you manually control the vehicle once every 10-15 minutes when using the automatic cruising feature on highways.

• Cannot use at night: Cruise control is of no use during night drives as the visibility is poor. Even with well-lit roads, the visibility is not as good as daylight. So, allowing the car to maintain a constant speed may be a safety concern, even on roads that are familiar to you.

• It does not work well with manual cars: In a manual car, you have to change gears by yourself. The cruise control will handle the acceleration/deceleration, but you still need to shift the gears manually to maintain the optimum RPM. It can be irritating at times when you need to slow down and accelerate immediately. It may not be a dealbreaker, but it kind of refrains you from experiencing the full potential of the automatic cruising system.

Cruise control vs adaptive cruise control: Key differences

The below table highlights the key differences between cruise control and adaptive cruise control.

What is the difference between cruise control and speed limiter?

Sometimes you may get confused between cruise control and speed limiter as both are related to the car's speed. Refer to the table below to understand the difference between both the systems.

List of cruise control cars In India

Cruise control is a feature that we can see in a lot of cars. Gone are the days when this feature was limited to premium vehicles. Even vehicles with affordable price tags are equipped with intelligent features. Here’s the list of popular cars with the automatic cruising system.

List of adaptive cruise control cars in India

Adaptive cruise control is the more advanced version of the standard automatic cruising system. Currently, this system can be seen only in premium cars in India. Below is the list of popular cars with adaptive cruise control.

Frequently asked questions