It's the road vibration because of the speed you're going, and it's also that when kids get comfortable and try to sleep, they have nothing to lean on and thus bend their necks at awkward looking angles when napping (because of being strapped in). I suppose you could try using a travel pillow, but with kids, it won't be around their necks for long (not to mention the helmet that gets in their way).
If you have two kids, it's better because they can lean on each other when sleeping. Never got the opportunity to use a solo trailer; always have used a double. And "smooth pavement" exists... theoretically.
Last edited by spambait11; 10-13-06 at 05:36 PM.