https://iopscience.iop.org/article/1...4/7/072005/pdf
This study shows that the angled and slopes wheel deflectors work much better than the straight flat ones most cars use. Think XL1 and light year one/zero car or the front deflectors of a Tesla or Porsche taycan.
Also it looks like “ shutter wheel covers” would be a thing of the future. Like auto grill shutters. The wheels would be fully closed but if they need brake cooling, the shutters will open some gaps in the wheels. Very interesting.