 For example, in the southern half of the highway, the "inner ring" is designated as the "Périphérique Ouest" ("Western Ring") as traffic flows westbound whereas the "outer ring" is designated as the "Périphérique Est" ("Eastern Ring") as traffic flows eastbound.In the northern half, these designations are reversed.The structure of the Boulevard Périphérique is similar to most French autoroutes, UK and Commonwealth nation motorways, and American freeways in the following regards