Actually if you drive faster on a wash boarded road it will smooth the ride out. I do it all the time in the outback.
Are your bumps 10-25 feet deep?
Does your vehicle have springs and shock absorbers?
How fast are you actually going in your car without springs and shock absorbers as you traverse 15 foot deep pot holes while performing complex tasks that you and others lives depend on for hours on end?
How well do you sleep while driving down that “wash board” road?