Autostrada A4 (Italy)

The Autostrada A4, or Serenissima, is a motorway which connects Turin and Trieste via Milan and Venice. The city of Venice (or rather, Mestre which is the "land" part of Venice) originally formed a bottleneck on the A4, but is now bypassed by the Passante di Mestre (the old route through Mestre was renumbered A57). The A4 passes just north of the city of Milan, where it is toll-free.

A4 Motorway
Autostrada A4
Autostrada Serenissima
Route information
Part of E70
Length	517 km (321 mi)
Existed	1927–present
Major junctions
West end	Turin
East end	Trieste
Location
Regions	Piedmont, Lombardy, Veneto, Friuli Venezia Giulia
Highway system
Autostrade of Italy

Due to the different companies that manage the different parts of the motorway, it is often referred to as formed by five sections: Turin-Milan, Milan-Brescia, Brescia-Padua, Padua-Venice and Venice-Trieste. As it runs through the whole Pianura Padana, which is a densely populated and highly industrialized area, A4 is one of the most trafficked motorways of Italy.

A4 is a dual-carriageway, six-lane motorway for most of its length. The stretch between Milano Est tollgate and Bergamo has been an eight-lane motorway since 30 September 2007. The stretch from Venice to Trieste is instead still a four-lane motorway, but it is planned to upgrade this stretch over motorway to six lanes.