Switzerland’s most important north-south motorway through the Alps will undergo a major upgrade, the government announced on Friday.
A report by the Federal Roads Office presented by the cabinet recommends closing the key traffic artery for up to two and a half years to carry out the extensive work.
The repairs will not begin before 2020 and will cost as much as SFr752 million ($782 million).
The authorities must decide whether to close the tunnel completely for 30 months, or spread the work out over a longer period in order to keep the road open in the busy summer time.
The motorway under the Gotthard massif is one of the few major roads linking northern Europe to Italy, and is therefore popular with holidaymakers heading south in summer, and is often the scene of long bottlenecks.
The Roads Office said that due to the national and international importance of the tunnel, finding alternative routes for traffic and freight transport would be essential.
The authorities will look into the possibility of transporting cars by train through the existing Gotthard rail tunnel, which will be replaced in 2017 by the 57km Gotthard Base Tunnel.
The government again spoke out against the idea of constructing a second road tunnel under the Gotthard, saying this would cost around SFr2 billion
swissinfo.ch and agencies