 Nevertheless, SS4 remains important to many mid-sized towns in Rome's hinterland, such as Settebagni, Monterotondo and Mentana.Passo Corese marks both the point where SS4 enters the Province of Rieti and the point where it diverges from Autostrada A1, receiving from it all traffic to the Adriatic.The road here leaves the Tiber valley and ventures into the more hilly Sabina region, commencing its long, gradual ascent to the Apennines.