Does cruise control increase fuel consumption? One of your correspondents mentioned that cruise control increases fuel consumption. Is this true? I have been a keen user of cruise control for many years and it is the only extra I ever have installed on any new car. Yes, because it robs you of the sensitivity of control via your right foot. Motorways are surprisingly undulating. If you leave the tripmeter on "instant consumption" you can see the economy dive on an incline if you maintain speed. But if you lift off a little bit and lose maybe 5mph, you might maintain reasonable economy. On a descent the opposite happens. When you could increase speed without burning extra fuel, the cruise control slows the car and economy suffers.