Abstract: In a vehicle with a power source for moving said vehicle and for spreading liquid material on a road surface a material distributing apparatus is provided which includes a hydrostatic transmission and associated control mechanism for automatically maintaining a constant application rate of the material to the road surface in response to changes in the width of the application pattern. The hydrostatic transmission is responsive to the power source for providing a controlled rate of flow of the liquid material from the tank of the distributing apparatus, to a discharge element of the apparatus and onto the road surface so as to maintain a constant rate of application for the material despite changes in the speed of the vehicle. A pattern adjustment mechanism is provided for adjusting the pattern provided by the discharge element.