Different perspectives here guys....if you are bucking on almost every road then to lawrosa's point you need to look at improvements to your set up as was detailed in many posts. On the other hand, JBarca pointed out that some roads are so bad that nothing but slowing down will help. The take-away here is that you can't prevent bucking ALL of the time, but with good equipment and a properly set up hitch you should be able to avoid it MOST of the time.
If you haven't yet followed the proper WD set up procedures detailed here, then it's a mistake to throw up your hands as some have suggested and say that nothing can be done.