Many drivers assume that using cruise control will always lead to fuel savings, but experts caution that this is not the case in all situations. Cruise control is particularly beneficial on flat, open stretches of road, such as motorways, where it can maintain a consistent speed and reduce unnecessary acceleration. This can lead to measurable fuel savings over longer journeys. However, on hilly terrain, the situation changes. According to a motoring expert from Interfuels, cruise control often fails to account for gradient changes, which can result in wasted momentum. For instance, when driving downhill, a driver can ease off the accelerator to utilize the vehicle's momentum, whereas cruise control may apply brakes to maintain speed, leading to increased fuel consumption. The expert emphasizes that studies demonstrating fuel efficiency with cruise control are primarily conducted under ideal conditions on flat roads. Consequently, experienced drivers who can read the road ahead may achieve better fuel efficiency than the cruise control system, which lacks the ability to anticipate upcoming changes in terrain.