I added references to research I've been involved on this topic and made some other changes to the page. Since then these references have been removed. I'm going to revert the changes. If you object or have comments on why these references shouldn't be there let's discuss.
Frost heaving is completely different effect to washboard road caused by freeze thaw cycles. Jim McElwaine (talk) 18:35, 11 January 2009 (UTC)
Well, your own website is a self published source. I think  would be a better link and establish this as a reliable source. Beeblebrox (talk) 21:15, 11 January 2009 (UTC)
And I took out the sentence about the contrasting points of view being in the references, as it is generally assumed that any information in the article is supported by the references. I also added a see also link for frost heaving as it is similar from the driver's perspective, even if the underlying causes are different. Beeblebrox (talk) 21:19, 11 January 2009 (UTC)
This page states that the "ripples will slowly grow and move in the direction of the vehicles," but there is no source for this claim. This page shows how the moguls on ski runs move uphill (against the direction of skier travel) and I would think that this would hold true for washboarding on roads as well. Dan Hickstein (talk) 18:47, 29 September 2010 (UTC)
Yes I'm familiar with this very nice work. Probably if the mogul skiers went fast enough the moguls would go downhill :-) This is a good point. There is little real observation from the actual roads. In lab experiments the ripples can go either way. I will update the page accordingly. Jim McElwaine (talk) 11:40, 1 May 2011 (UTC)