Abstract: A vehicle mounted spreader for spreading materials such as sand, salt, or other granular chemicals onto snow and ice covered road surfaces comprises a hopper for containing the material to be spread, a spinner for spreading the material, a conveyor for conveying the material from the hopper to the spinner, a vehicle speed sensor, a load sensor, and a controller programmed with an intended density of material (e.g., pounds per acre) and desired width of coverage; within the controller the vehicle speed sensor measurement and load sensor inputs are processed to generate outputs to control the speed of the conveyor and spinner, to both control the rate of material distribution and the pattern of material distribution to approach the intended density and width.