How does speed affect the rebound effect in car travel? Conceptual issues explored in case study of 900 Formula 1 Grand Prix speed trials

The "rebound effect" occurs when reductions in energy consumption following energy efficiency increases are lower than engineering estimates. In cars this happens when drivers increase their distance travelled or average speed, as a behavioural response to cheaper travel. Rebound effects due to increased distance travelled have been extensively studied, but only one existing study attempts to quantify rebound effects due to increased average speed. This paper builds on that study, using a much larger empirical base and offering more generalised and more widely applicable mathematical modelling. It uses data from 30 Formula 1 Grand Prix time trial sessions of 10 vehicles doing 3 trials each, in 2014 and 2015. The heavily regulated Formula 1 regime, with its precisely measured data, provides a highly controlled framework for developing mathematics of average speed rebounds. The study thereby shows how speed and distance rebounds can be coherently combined in road vehicle travel to produce total rebound figures. It then shows how even small increases in average speed can nullify all the energy savings that are expected from energy efficiency increases. It also raises critical questions on the adequacy of proposed new road vehicle fuel efficiency testing procedures. - Highlights: • Rebound effects in car travel have been well studied for distance but not speed. • But speed rebound effects reduce fuel savings from energy efficiency upgrades. • A mathematical model is developed for dealing with average speed rebounds. • This model is tested with precise data from 900 Formula 1 Grand Prix time trials. • It is shown how speed and distance rebounds can be combined in everyday car travel.