Fun RV Living Fact of Life: How are Washboard Roads Formed?
We’ve all encountered them, and those of us who love to boondock on BLM land and National Forests drive on them a lot. Those ridged, bumpy, wall rattling, dish-clanking, drive shaft clunking, dirt or sand roads that are annoying as hell to drive on. So where do they come from? How do those ridges get created?
I finally looked up what causes dirt roads to washboard and ripple!
I figured you might be curious about this too!
There have actually been laboratory studies done and articles published in science journals about the phenomenon. And from what I’ve read, the science seems to be inconclusive.
Most road and physics experts believed washboarding (also called corrugation) is caused by a lot of traffic traveling on loose dirt, sand or gravel roads at speeds greater than 5 mph. An automobile’s suspension causes the tires to bounce, putting pressure on certain parts of the road, pushing up the sand or gravel, thereby causing ripples.
However, laboratory studies have shown that even when “springy suspension of the car and the rolling shape of the wheel are eliminated”, washboarding occurs (source: Science Daily article “Physics of Bumpy Roads: What Makes Roads Ripple Like a Washboard?”)
So, while heavy traffic and suspension may be part of the problem, it seems there may be other (currently unidentifiable) factors at play.
How to drive on washboard roads
The next question is: how the heck do we drive on those annoying washboard roads safely and efficiently? Is it better to slow down or speed up?
I went to one of my favorite sources for this answer: MythBusters.
According to MythBusters and their field test, with a 1970 Cutlass Supreme, driving at 5mmph and then at 70 mph, they found that yes, indeed, at 70,mph, it is a smoother ride and the “high-speed camera footage revealed that the faster-moving wheels literally move across bumps in the road” (MythBusters, “Bumpy Ride“).
So, at higher speeds a vehicle can literally glide over the bumps whereas at 5 mph you feel every single one – and it prolongs the agony, right?
However, their test was with a Cutlass Supreme, not a 29′ Class C RV with all kinds of stuff to rattle around and make noise. I’ll stick with 5 mph!
How about you? Do you prefer to fly over them or take it slow?