FIGURE 5-2 University of Maryland, streamlined tractor, closed gap, three-quarter trailer skirt, full boat tail. SOURCE: Cooper (2004), p. 15, Fig. 4, Case 8. Reprinted with kind permission of Springer Science and Business Media.

Industry interest was encouraged by the graphic illustrations produced by the National Research Council of Canada, as shown in Figure 5-3.

The introduction of the Kenworth T-600 in 1985 marked the industry’s first serious attempt to incorporate aerodynamic improvements in truck tractors (see Figure 5-4). The T-600 included features such as a streamlined hood and fenders, an aerodynamic faired bumper, fuel tank fairings, and air filters mounted under the hood. These changes resulted in a significant reduction in aerodynamic drag compared to contemporary tractor models.

Continuing development led to additional improvements such as cab extenders to reduce the gap between tractor and trailer, more aerodynamic mirrors, and full-length side fairings. By 1990 all major truck/tractor manufacturers had introduced aerodynamic models, although “traditional” models continue to be available. See Figure 5-5 for identification of the common aerodynamic features.

FIGURE 5-3 National Research Council of Canada: Smoke pictures, cab with deflector (right). SOURCE: Cooper (2004), p. 11, Fig. 2. Reprinted with kind permission of Springer Science and Business Media.