A unified equation for predicting traction for wheels on sand over a range of braked, towed, and powered operations

•Existing traction equations predict values only for one mode of operation.•A unified traction algorithm is proposed for braked, towed, and powered wheels on dry sand.•The algorithm is developed using DROVE database.•The algorithm employs the ratio of contact pressure to cone index.•The new equation can be implemented in VTI and other off-road mobility models.