For washboard roads there is only one way to drive on them. There is one speed that is optimum. You have to go fast enough not to jar your molars, but not too fast that you fishtail and lose control. It’s a balancing act that is a lot of fun (like a demolition derby) unless you have a nice car and not a truck. Usually you have to go fast enough that the dust cloud doesn’t overtake you. LOL !