Crossbars with curved profile
Curved
— profile designed to reduce air resistance.The specific design of such crossbars may be different. Nowadays, the most common oval (symmetrical or almost symmetrical) and teardrop-shaped (elongated and narrowed towards the back) profile shape; the first is easier to manufacture, the second is somewhat more efficient. However, anyway, the aerodynamic shape of the rails reduces air resistance, and, accordingly, the noise level and fuel consumption. The reverse side of these advantages is a rather high cost compared to a rectangular profile.