Does Cruise Control Save Gas? What You Need To Know

Cruise control is more than just a feature car reviewers and dealers mention in passing while discussing a vehicle. Invented in the 1940s, this mechanism that locks a car at a set speed started to be adopted widely in the 1970s, although many people didn't know how cruise control works and when to use it. For a time, carmakers highlighted it as a selling point. But today, it comes standard in almost all cars.

People who have driven long distances understand how demanding it is to maintain high speeds on the highway. It requires stepping on the accelerator pedal continuously, which can be strenuous to the foot and other muscles. With cruise control, drivers don't need to worry about maintaining a constant speed while traversing flat highways or gentle slopes. The mechanism keeps the speed steady unless the driver hits the brakes.

Since cruise control eliminates much of the need to use the accelerator, does it also save on fuel? According to the South Korean carmaker Kia, it does cut down on fuel consumption, by an average of 7% to 14%. Meanwhile, a study by Natural Resources Canada found that cars consume 20% more fuel when driven at fluctuating speeds compared to when cruise control is on. 

However, since not all roads are the same and traffic conditions vary, the feature isn't always useful. This could be the reason why it needs to be manually switched on with a button on the steering wheel or dashboard.

Cruise control is most effective on flat, open highways where traffic congestion is minimal. Electronics do better than a human foot at maintaining a consistent speed and avoiding frequent speed-ups and slow-downs that waste fuel. Small changes in momentum require extra energy, as force equals mass times acceleration, ultimately increasing fuel consumption. On steady uphill or downhill roads, cruise control helps maintain fuel efficiency.

However, its effectiveness diminishes on roads with rolling hills or sharp inclines. In such conditions, it's better to deactivate cruise control and manually adjust driving speed. Allowing the vehicle to naturally slow down while climbing and pick up speed during descents can save more gas. Interestingly, for electric vehicles, the story is slightly different. Regenerative braking allows them to recover much of the energy spent climbing hills, making cruise control more viable even in hilly areas.

While cruise control is a valuable tool for improving fuel efficiency, it's important to use it responsibly. It should never be activated in hazardous weather conditions, such as heavy rain or icy roads. On slick surfaces, even slight acceleration can cause the vehicle to lose traction, potentially leading to dangerous understeering or oversteering situations. In these cases, sudden braking to deactivate cruise control can further compromise control and increase the risk of accidents.

An advanced version of the driving feature, adaptive cruise control, comes with more sophisticated components, including sensors and radar, to automatically adjust a car's speed to match that of the vehicle in front of it. Hence, it both saves fuel and doubles as a collision-prevention feature.

On the whole, aside from promoting fuel economy, cruise control reduces wear and tear on the car's drivetrain by minimizing unnecessary acceleration. However, it's imperative to always prioritize safety over fuel savings. Pay close attention to road signs, traffic, and weather conditions, turning off cruise control whenever circumstances demand manual control of the vehicle.