Many of these fuel efficient vehicles do not deliver near their optimum fuel economy since driver variables and operational conditions may change a vehicle's inherent fuel economy. Small operational changes and poor vehicle maintenance account for the widely varying average MPG delivery for similar vehicles. These two measures may improve a typical vehicle's MPG by 0.1. Rapid acceleration and procrastinating applying the brake for the upcoming stop sign or red signal light may reduce MPG from one to two tenths mile per gallon to one MPG or more. Many drivers fail to plan their daily trips.
Proper planning can save fuel dollars.
Heavy traffic and long turning delays increase idle time. By driving above the posted maximum speed limit, the vehicle not only uses more fuel, but the driver is more likely to brake more frequently. Each time the brakes are applied, the laws of physics tell us that the vehicle's energy is being burned up. The more rapid the stop, the more quickly energy is being wasted. Gradual acceleration, driving at a moderate speed, and smooth stopping can help a vehicle deliver its optimum fuel economy.