I don't see much talk about that self-evident fact. Asphalt sucks in so many ways. What would be a better alternative that needs not worry about cars but mostly bicycles?
Pavestone (including Belgian pave just like what was used on Paris-Robaix) and dirt are good only if you have big cushy tires or a suspension fork. Or assuming dirt roads don't get dusty or muddy enough to get you blinded temporarily or splattered or forced to get off and walk through the mud.
Where I am, it's either asphalt or concrete, but how good are they depends on the subcontractor and the quality of materials bought. And of course, I ride a dirt road only if either I don't have much of a choice or I'm feeling sporty than commuting.