• C275 AQP 1
  • C275 AQP 2
  • C275 AQP 3
  • C275 AQP 4
  • C275 AQP 5
  • C275 AQP 1
  • C275 AQP 2
  • C275 AQP 3
  • C275 AQP 4
  • C275 AQP 5

Sassari Olbia Highway

Client Regione Sardegna – ANAS S.p.A.
Services provided Preliminary design , Environmental Impact Study
Period of execution 2006-2012
Construction cost € 705,837,039.00

74 km of total length
17 interchanges
158 km of secondary roads
Bridges 24 - 11 viaducts and 4 overpass
section type B (DM 05/11/2001), with two lanes in each direction and central reservation


The Sassari-Olbia highway is the main crossing between the east and west coasts in the north of Sardinia and forms part of the ‘fundamental structure’ of the Sardinian Region’s road system. It is strategic for the island’s development and growth prospects since it connects two major towns in the north, two ports (Olbia and Porto Torres) and two airports (Olbia and Alghero). At present the road is a single carriageway with two lanes, with junctions at the same level and consequent low speed. It carries a significant volume of traffic for such a road section and accident rates are high. The project makes provision for a dual carriageway with two lanes each and a central reservation for an overall length of 74km with the adaptation of the SS597 (mostly flanking the existing route), 17 road crossings and a series of bridges and viaducts with a length of up to 300m.


Based on the function of the new highway, the design approach considers the prime objectives of function, development and safety:

  • its function as a new fast motorway-type connection between the two major commercial poles of Sassari-Alghero-Porto Torres, and Olbia-Golfo Aranci
  • providing development prospects not only for either end of the road itself, but also for the surrounding area, thanks to better connections with Sassari and Olbia, while maintaining a capillary local road system needed to encourage tourism
  • safety thanks to the incorporation of all the most recent road and water runoff regulations, this latter factor having become extremely sensitive after recent disasters in the area caused by heavy rainfall

The road layout was defined after a technical-economic analysis of various alternatives, analyzing and comparing practicality, safety, environmental protection and cost. In particular, three alternatives were examined: widening the existing road; building the new road beside the existing track; and selecting an improvement route. A special study was carried out to assess the extremes of the intense rainfall phenomena recorded over the past years, constructing new rainfall probability curves and on that basis assessing areas subject to flooding both before and after the works, with return times of 200 and 500 years, even for small basins. Great care has taken in designing secondary road systems reconnecting the area: over 150 km of reconnection, improvements and upgrading of roads affected and flanking the new highway, always seeking the best compromise between performance and practicality on the one side and safeguarding the environmental, agricultural and social context on the other. The new road is included in an area with an ecosystem including protected fauna, making necessary mitigation works such as underpasses for fauna, etc. An examination of the area’s archaeological assets was carried out with studies of the sources and surveys. The results have been filed in a risk index and have led to project changes (minor changes) and/or design adaptations. The fact that the route frequently runs parallel to the railway line has led to problems of safety for both infrastructures, resolved in agreement with the railway management (RFI) by placing barriers with protective netting along the sides of bridges.


Provided in collaboration with SERV.IN

  • Preliminary design
  • Study of hydraulic compatibility to Hydrogeological Spazial Planning PAI
  • Environmental Impact Study SIA