Vehicle Shape is Vital to Over-the-Road Efficiency

When all things are equal, the vehicle shape shows the greatest differences in fuel economy.

Rarely ever is there a constant wind speed or direction in over the road travel, these ever-changing characteristics of aerodynamic resistance make it a complex force to overcome. All things being equal, the average mpg of an over-the-road vehicle will vary plus or minus .50 to 2.00 miles per gallon from day to day primarily due to variances in weather conditions relative to the vehicle's shape.

Maximum, more consistent vehicle efficiency is achieved when the vehicle shape responds to all wind speeds and directions with relative consistency. Allowing for smooth uninterrupted airflow regardless of the wind's angle of approach, aerodynamic shaping provides the greatest possible improvement in fuel economy. See Table 1 for a list of shapes and their drag coefficients.

The nose cone was originally shaped to offer minimum aerodynamic resistance for the forward most section of a rocket. Nose Cone Manufacturing Company adopted its name from this simple principal used by aeronautical engineers; maximize efficiency by minimizing aerodynamic resistance through shaping.