Thought I should share the knowledge, having tried something a bit different on this image. Added bonus it was something which actually worked. you may find it useful doing vehicles in motion which can often be a challenge in 3D Art. I used Poser and Photoshop, but the principles are transferable to Daz Studio and any other half decent photo editor. I rendered the whole image and then did a second render pass with only the wheels visible. Literally everything else in the scene was deleted or hidden, even the terrain and backdrop. I then added the second render as a separate a layer in photoshop. I selected each wheel. The easiest way to this being to select the transparent area, invert the selection and deselect the other wheels. I then applied a radial blur and cut away the bits that were behind other objects in the scene. Don't attempt to do all the wheels together as the radial effect will be applied over the image as a whole rather and will look awful. I then added a new layer to create the sand plume (using brushes from Ron's Powder) and gave it a little motion blurring. Finally I flattened the image. It worked rather well and not as tricky as I suspected.