@Rod kinetic energy?
At low speeds, only a small fraction of the energy burnt is used to propel the vehicle. Most is turned into heat by the internal combustion engine. The shorter the time the car is producing that heat, the lower the energy used. So to improve efficiency you need to travel faster.
Going faster does increase rolling, mechanical and wind resistance but the balance point is around 55mph (vehicle specific).

I’m glad you realise that energy is wasted as cars have to avoid obstacles – can I suggest you campaign to remove the worst offenders, speed bumps?