Aerodynamic design improved the mileage figures for U-HAUL's largest fleet truck. Rounded front corners enable the establishment of laminar air flow over the van body top and sides. These corners of 150 mm (6 inch) radius, developed six years prior and currently produced on several smaller trucks and trailers, provided a comparable mileage improvement with all designs tested. From test data analysis it was determined that, in the U-HAUL environment, aggressive streamlining, to the extent of current technology, provides little practical advantage over the rounded corners. Various other fuel saving devices were investigated; of those explored, none exhibited a significant mileage gain.