Roads & Motorways

A1 motorway: Florence North-South

Widening to three lanes
Owner/client SPEA Ingegneria Europea S.p.A.
Type of service Detailed Design
Location Florence
Period 1999 - 2003
Cost € 392.300.000

The project concerned upgrading the stretch of the A1 motorway between the Florence North and Florence South junctions.

The measure consists in widening the infrastructure from two to three lanes per driving direction in the stretch of the A1 'autostrada del Sole' included between the junctions of Florence North and Florence South, implemented by means of (symmetric and asymmetric) widening of the existing motorway or very close to it.

In particular, the upgrading consists in: widening from two to three lanes of the current motorway, in the stretches not covered by the existing tunnels; creation of a new three-lane carriageway in south direction, in the stretches covered by the existing tunnels, between Certosa and Florence South; upgrading of the two existing carriageways, which shall both be opened to traffic in north direction, where the alternative routes originate, in the stretch covered by the existing tunnels between Florence South and Certosa.

Intervention length

About 22 km

South carriageway

2 natural tunnels ('Melarancio', 1096 meters long; 'Pozzolatico', 2420 meters long

Certosa junction

3 natural tunnels ('Le Romite', 264 meters long; 'Poggio Secco', 1231 meters long; 'Del Colle', 667 meters long)

Along the stretches where the new southbound carriageway (Rome direction) follows a different route to the existing one, two important underground natural excavation works were entailed (Melarancio tunnel, L=1096 and Pozzolatico tunnel, L=2420 m); it should be noted that, when designing the underground structures and altering the size of the roadbed, great attention was paid to aspects linked to the safety of users in emergencies (special equipment and structures, such as an underground escape passage for pedestrians under the roadbed).

Besides increasing the width of the motorway roadbed, the upgrading entailed several connection and interchange works with the infrastructures and services found in the area. In particular, the connection between the new road (at the Certosa junction), Certosa station and the clearway for Siena is provided by a new stretch of direct link road which runs through three natural tunnels (Le Romite tunnel, L=264 , Poggio Secco Tunnel, L=1231 m and Del Colle Tunnel L=667 m).

Furthermore the project included several design and technological solutions to improve the quality of the environment surrounding the new stretch of motorway in order to fit the structures into the landscape and mitigate the environmental impact its use will inevitably have. The project not only reduces current levels of pollution, but also includes additional works, such as rationalization operations on the local road network and park and ride car parks, which contribute towards a more functional development of transport in general and make it easier to upgrade public transport.

The mitigation of impacts on the surrounding environment has focused on the control of noise and air pollution and the recovery of a proper balance, through the construction of works of "environmental insertion" between the freeway and inhabited areas, among which we highlight the 'Casellina' artificial tunnel.