We could recover the energy. mgh = 0.5mvv Cancel out the mass, round g to 10 m/s/s, assume a velocity of 30 m/s, and solve for h: h = 45 We thus need a rota

We could recover the energy. mgh = 0.5mvv Cancel out the mass, round g to 10 m/s/s, assume a velocity of 30 m/s, and solve for h: h = 45 We thus need a rotary that is elevated 45 meters above the road. That is about 150 feet. This could work for a highway, especially if it is in a road cut.