I just picked up my 2020 RAM 3500 in the rain, and by the time I got home the running boards and the sides of the truck and back tailgate were covered in dirt. The next day I got a break in the rain long enough to install the mud flaps before the next round of rain. What difference the mud flaps made, running boards, sides and tailgate had very little dirt, and we have been down some dirt roads.
Mud flaps were easy to install, very pleased with performance.