There is a kind of conveyor belt whose cross-section is isosceles trapezoid or approximately isosceles trapezoid. That is the v belt. V belt drive torque. Also the service life of v belt is longer than common conveyor belt. V belt under normal use can reach the length at 4 million to 5 million km.
V belt was first used in the engine radiator fan drive. V belt has gradually been replaced by the ribbed belt. V belt drive pulley with the contact areas are toothed, flat, and the form of composite structure. Now v belt is gradually moving to tooth structure. Tooth structure of the v belt has good flexibility and heat dissipation characteristics. So v belt could be applied in small wheel diameter. V belt usually can not use automatic tensioner, so v belt manually adjust the tightness. That may be a disadvantage of v belt.
However as the conveyor belt industry improving, the v belt also could get more developments.