Advanced Driver Assistance Systems (ADAS) such as adaptive cruise control, anti-lock braking systems, and collision avoidance systems, to name a few, improve driver safety and experience.
The adaptive cruise control is an upgrade to the traditional cruise control as it comes with better features.
But unlike its predecessor, the adaptive cruise control maintains a safer set distance between your car and the lead vehicle.
In fact, it’s very beneficial, especially for long-distance highway driving. But given that gas is a precious commodity that ought to be used efficiently, does adaptive cruise control use more gas?
Driving with adaptive cruise control saves you gas compared to driving manually. A car cruising at a constant speed consumes less gas than one fluctuating in speed, as with manual driving. However, adaptive cruise control is only fuel-efficient in relatively flat grounds.
And since most parts of the country are relatively flat with slight variations in altitudes, it’s safe to conclude that adaptive cruise control saves gas.
Read on to learn how adaptive control saves gas, times when it doesn’t, and how it works with a manual transmission.
How Adaptive Cruise Control Saves Gas
As we’ve seen, adaptive cruise control keeps a vehicle at a constant cruising speed, especially on relatively flat roads. Additionally, adaptive cruise control accelerates or decelerates a car with respect to a car that’s directly ahead.
And unlike manual acceleration, the system changes car speeds in a smooth, incremental way. Aggressive acceleration and deceleration are less fuel-efficient, and you may end up using more fuel than a smooth driver.
Furthermore, even if you’re not an aggressive driver, varying the speed every few seconds while shifting your foot position on the pedal consumes fuel.
The slight acceleration and deceleration as you press on the gas pedal will ultimately sum up to a significant figure that, in the end, lowers your car’s fuel economy.
Moreover, a study by Kia shows that cars with the adaptive cruise control feature use 7-14 percent less fuel than most manually driven cars.
However, drivers’ driving styles vary significantly, with some being smooth on the throttle while others are very aggressive. The smoothest drivers will save more fuel than the aggressive ones in the long run.
When Does Adaptive Cruise Control Consume More Fuel?
Adaptive cruise control may be worse than manual driving when driving in stop-and-go traffic or while on hilly grounds. The extent of fuel consumption will vary depending on your car.
A reason for this is that vehicles are programmed to respond differently to terrain or traffic changes while adaptive cruise control is active.
The US Department of Transportation, through its Intelligent Transportation Systems Joint Program Office, concluded that adaptive cruise control could save fuel by as much as 2.8 percent on the highways. But it doesn’t specify how the system performs on heavy traffic or hilly roads.
Regardless, all vehicles will consume more fuel while going uphill than when going down a slope.
Cars have a narrow range of engine revolutions that deliver optimum power while saving fuel. For example, your automatic car will pick perfect gear when going uphill or downhill to save fuel.
You’ll have to downshift or upshift your gear lever if you’re driving a manual car. The challenge is that depending on the manufacturer, some cars are more aggressive than others and will increase engine revolutions than necessary.
Hence, some cars with adaptive cruise control will consume more fuel than others when you’re driving manually.
When Does Adaptive Cruise Control Consume More Fuel?
For those that prefer manual vehicles, it may be tempting to know how adaptive cruise control works on such a vehicle. How does it decelerate or accelerate to a certain speed if you manually shift the gears?
Manual transmission cars equipped with adaptive cruise control aren’t the best fit if you plan to use them for stop-and-go traffic. The adaptive cruise control will only be effective for speeds close to 20 miles per hour or higher, depending on the car.
Furthermore, it will automatically disengage if you press the clutch pedal for older manual transmission car models.
You’ll need to activate the adaptive cruise control for manual transmission cars every time after downshifting.
If the system detects that the revolutions per minute (RPMs) are either too low or too high for a given gear, it will automatically disengage.
A reason is that very low RPMs will stall your car. The adaptive cruise control doesn’t want that to happen while you’re cruising.
If you’re following a decelerating car, your adaptive cruise control will notify you to take charge and downshift to a lower gear.
It will then deactivate itself to prevent stalling. And, if you’re on hilly ground or winding roads that need a frequent change of gears, it’s better to drive without cruise control.
Does Adaptive Cruise Control on a Manual Car Allow Low-Speed Follow?
A low-speed follow is an adaptive cruise control feature that uses a camera and sensors to gauge the distance between the lead car and your car in low-speed cruising.
You can use it in city stop-and-go traffic if you don’t wish to drive your car manually.
Unlike cars with automatic transmission, manual transmission cars with adaptive cruise control don’t have the low-speed follow feature.
The reason is that with a low-speed follow, you will still need to shift gears to a point where having the feature in a manual car is a waste of money.
And while the low-speed follow feature works well in an automatic transmission vehicle, it’s redundant in manual transmission cars.
It’s pretty standard nowadays that most new cars have the adaptive cruise control feature. And in addition to improving driver safety and comfort, it also enhances a vehicle’s fuel economy.
However, be very cautious while driving on the road while your adaptive cruise control is on. It’s meant to complement your driving, and you’re liable if an accident occurs while you’re cruising in your car.
Furthermore, don’t use adaptive cruise control on winding roads and poor visibility zones like dust storms and fog. Winding roads are especially dangerous on the corners as your car might lose track of the lead car and inadvertently start accelerating.