Along Via Flaminia, towards the valley of the Nera River in Narni, there is one of the most impressive works of the whole road, the Augustus Bridge. Here there is a fork, with one rectilinear road that continues to Carsulae and Bevagna, and one that crosses Terni and Spoleto, then rejoining the first section near Forum Flaminii.

The presence of two different roads is due to the different tasks of the road, that on the western side goes through a large rectilinear road, and on the eastern side crosses a strongly urbanised road, which has a higher economic and commercial interest.

Along the western side, on the Calamone Bridge and the Caldano Bridge, Via Flaminia goes up to the present Sangemini and immediately afterwards crosses Carsulae, a city founded precisely because of the road. In the city of Acquasparta there is the important sostruction of a Bridge, Valle Petrosa, built as a polygonal work, whose construction technique, different compared to any other structure of the road, probably relates to the original architectural style of the 3rd century b.C., the period in which Via Flaminia was outlined.

The Fonnaia Bridge, erected more northwards, marks the border with the city of Massa Martana: the structure is imposing, apparently excessive compared to the limited size of the watercourse that it crosses.

In Spoleto, outside of the northern gate, there are the ruins of the Ponte Sanguinario, erected at the times of the Augustan revision. .