The optimum fuel economy speed will be different for every car and vehicle.
When the RAC completed its Record Road Trip in the Audi A6 Ultra, that particular car’s optimum fuel economy speed was 52mph in seventh gear on the flat.
While there is an ideal speed, road conditions and gradients will often mean that road users cannot drive at their optimal speed.
Motorists have to use hypermiling techniques, by improvising and adjusting their driving according to the road ahead.
