The city chambers said the “first phase of the works are going to last three months and only in the period between 22:00 and 06:00 -, so as to ensure traffic flow during the day".

This first phase of the works is between the end of the A1 motorway from Porti and Avenida de Berlim, which runs from the airport down to the Oriente train station.

Once these works are finished, a much bigger job is going to start on the remaining 10 kilometres of this major urban freeway between the airport and the far end of the ‘Segunda Circular’ lasting another eight months.

The works are going to include planting bout 500 beech trees, widening the central separator, new signs and crash barriers.

The ‘Segunda Circular’ was first built in the 1960s and this is the first major up-grade in over 50 years, the city chambers said.