First section of Lot 4 of the SS 223 “Grosseto–Siena” opened to traffic

10 March 2026

March 10, 2026 marks an important milestone for the upgrading program of the SS 223 “Grosseto–Siena” State Road: with the opening to traffic—thanks to the commissioning of the VI05 viaduct and the diversion of circulation onto the new alignment—the first section of Lot 4 is now in operation, where Itinera is working together with Monaco S.p.A.
This infrastructure, a strategic axis connecting the inland area of Siena with the Tyrrhenian coast, thus moves forward toward its final modernization. The opening allows traffic to be routed onto the new road alignment, easing the load on the existing roadway and enabling construction activities to continue on the sections still under development.

The viaduct, 475 meters long, overcomes the planimetric and altimetric constraints of the historic route, ensuring a more regular longitudinal profile and improved visibility conditions for road users. From a structural standpoint, the structure also guarantees high load-bearing capacity, adequate seismic resistance, and reduced maintenance requirements throughout its life cycle.
For its construction, more than 7,000 cubic meters of structural concrete and about 800 tons of reinforcing steel bars were used, in addition to 2,200 tons of self-protecting steel structures—also known as Corten steel—for the beams.

With the activation of the new alignment, construction activities are now effectively separated from traffic, improving operational conditions for completing the remaining works and enhancing user safety.
For the Maremma area and the entire Grosseto corridor, this achievement anticipates the benefits that will come with the full completion of Lot 4.

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