Have climbing fuel prices got you down? It is safe to say a 10% or 15% reduction in monthly fuel expenses would be worth your time and effort; would it not? You can reduce fuel expenses in four ways: Buy fewer gallons of fuel by reducing engine hours operated, maximize engine efficiency, reduce miles driven, and reduce vehicle rolling resistance. While you may presume that engine hours and miles driven directly correlate and are somewhat redundant, that is frequently not so.