What even is the point of cruise control?!

Cruise control has long been celebrated for enhancing driver comfort during extended journeys. If you've ever driven from Melbourne to Lakes Entrance, for example, you will know what I mean. Beyond reducing fatigue, many drivers are curious about its impact on fuel efficiency. Does utilising cruise control lead to noticeable fuel savings? The answer isn't straightforward; it depends on various factors, including driving conditions, terrain, and the specific vehicle in use.

Understanding Cruise Control

Essentially, cruise control is a system that automatically maintains a vehicle's speed without continuous driver input on the accelerator pedal. Early versions mechanically locked the throttle at a set position, but modern systems are electronic and more sophisticated. Advanced variations, known as Adaptive Cruise Control (ACC), can adjust speed based on traffic conditions, maintaining a safe following distance from the vehicle ahead.

Cruise Control and Fuel Efficiency

The primary advantage of cruise control in terms of fuel efficiency lies in its ability to maintain a constant speed, thereby reducing unnecessary acceleration and deceleration. On flat terrains and open highways, this steadiness can lead to fuel savings. According to a study by Natural Resources Canada, setting cruise control at 80 km/h resulted in up to 20% fuel savings compared to fluctuating speeds between 75 and 85 km/h.

Kia

That said, however, the benefits of cruise control are not universal across all driving conditions. In hilly or mountainous terrains, cruise control may strive to maintain a set speed uphill, causing the engine to work harder and consume more fuel, not to mention the annoying noise this makes. Conversely, it might not adequately utilise engine braking downhill, leading to potential safety concerns and inefficient fuel use. In such scenarios, manual control allows the driver to anticipate changes in terrain and adjust throttle input more judiciously, optimizing fuel consumption.

Adaptive Cruise Control (ACC) and Fuel Consumption

Adaptive Cruise Control represents a significant advancement over traditional systems by incorporating sensors to monitor traffic and adjust speed accordingly. While ACC enhances safety and convenience, its impact on fuel efficiency is nuanced. Research from Argonne National Laboratory indicates that current ACC systems may be approximately 2% less energy-efficient than skilled human drivers, particularly during steady cruising conditions.

VMS Taps

This slight inefficiency arises because ACC systems react to the behaviour of preceding vehicles rather than anticipating traffic flow, leading to minor but frequent adjustments in speed. Human drivers, especially those practicing eco-driving techniques, can often predict traffic patterns and adjust their driving more smoothly, conserving fuel.

Factors Influencing Fuel Efficiency with Cruise Control

1. Terrain: As previously mentioned, flat terrains are ideal for cruise control to maximize fuel efficiency. In contrast, hilly terrains may negate its benefits.

2. Traffic Conditions: In heavy traffic, constant speed adjustments are necessary, making cruise control less effective. It's best utilised in light traffic conditions where steady speeds are attainable.

3. Driving Habits: Drivers who naturally maintain a steady speed may see less dramatic fuel savings from cruise control compared to those with variable speed tendencies.

4. Vehicle Type and Technology: Modern vehicles equipped with advanced cruise control systems and fuel-efficient technologies may experience different impacts on fuel consumption compared to older models.

Best Practices for Using Cruise Control

• Optimal Use: Engage cruise control on highways with minimal traffic and flat terrains to maximize fuel efficiency.

• Stay Attentive: Always remain vigilant. While cruise control manages speed, the driver is responsible for steering and monitoring road conditions. And if your cruise control sounds as if it's straining or stuck in between gears, that's a good indicator human pedal control is a better option.

• Adapt to Conditions: In adverse weather or on slippery roads, it's advisable to disengage cruise control to maintain full control over the vehicle.

• Understand Your Vehicle: Familiarise yourself with your vehicle's cruise control features and limitations by consulting the owner's manual.

Conclusion

Cruise control can contribute to fuel efficiency, particularly during steady-speed driving on flat highways. However, its effectiveness is influenced by terrain, traffic conditions, and individual driving habits. While it offers comfort and can reduce driver fatigue, it's essential to use cruise control judiciously and remain attentive to driving conditions. For personalised advice on optimising your vehicle's fuel efficiency or addressing cruise control issues, consult with our mechanical automotive professionals here at BM Tech.