Down the Roman Road: Part I

I have been thinking about those ancient roads that run through parts of the Roman Forum, the Appian Way, and Pompeii, and have come up with a few questions. I have often walked along or across these roads, paying particular attention not to turn an ankle or fall on my face. All the while I think that the roads must certainly have been more pedestrian-friendly in the ancient world. I have searched for answers by wandering through the tangle of information that is the internet, and I have also been so bold as to post my queries and thoughts on the LatinTeach list and the budding Google+ network. Either it is summer and many who would contribute or comment are lounging at the beach, or more likely my questions interest only me. In any case, I have decided to place my efforts for storage and future consideration.

The Via Sacra in Rome

Question #1: Why are these roads so rough?

While some weathering has certainly occurred over the centuries to round off these stones, I doubt that they could have changed all that much. The roads paved over in large blocks of basalt in the city of Rome are very similar, if not identical, to those which have been unearhted in Pompeii over the past few centuries. I think that it is possible or even probable that sand, gravel, concrete, or other aggregate was certainly added to fill in the gaps betrween the stones, level off the surface, and create a smooth pavement. This filler would certainly have been weathered away on the exposed, paved roads of Rome and the Appian Way. Also, any loose surface material could have been innocently swept away when the streets of Pompeii were being excavated. As archaeologists in Pompeii continue to make their way down a buried street, perhaps they should pause as they get down to the paving stones and see whether something besides ash or volcanic debris can be found on the surface.

My only concern with the use of sand or dirt as a "smoothing agent" is that they would be easily washed away by the rain or waste water which would flow through the thoroughfares.