Rome Off The Beaten Path Tips by mccalpin

Via Appia Ancient Rome Review

The Via Appia was the main Roman highway that went south towards Naples. Outside the city limits, Romans buried their dead (as required by law), so the Via Appia collected a lot of tombs.

On Sundays, Romans since ancient times have ridden out the Via Appia for a pleasant drive and a picnic among the tombs - it's not macabre, it's actually very pretty.

The attached photo is of the Via Appia in one of the sections that has been paved over with asphalt. Note that there are sections that still have the original Roman stones.

Much of this area is now a park. See http://www.parcoappiaantica.org/en/default.asp for a great website in English for the park that contains monuments, catacombs, and the Via Appia Antica.

You will see that on Sundays and holidays, that the park is shut down to traffic and becomes a giant pedestrian zone, so I would say that walking on those days is not only safe, but encouraged.