A4 autoroute

The A4 Autoroute, also known as autoroute de l'Est (English: Motorway of the East), is a French autoroute that travels 482 km (300 mi) between the cities of Paris and Strasbourg. It forms parts of European routes E17, E25, E46 and E50. It is France's second longest after the A10 autoroute.

Its construction began in the 1970s near Paris. The first section between Porte de Bercy, in the south part of Paris and Joinville-le-Pont opened in 1974 with a single carriageway. A second carriageway was added in 1975, and the following sections between Joinville and Metz were opened in 1975 and 1976. Former autoroutes A320 and A34 were integrated into the A4 in 1982. The A32 was renamed to A320 in 1996.

From Paris, the autoroute passes the new town of Marne-la-Vallée and Disneyland Paris. It continues on to some of the major cities of France's northeast, including Rheims and Metz, before terminating in Strasbourg. Local roads provide a connection to southern Germany.

Its westernmost part between the Périphérique and the A86 ring road in Paris is reputed to be one of the busiest sections of road in Europe, with 257,000 vehicles a day recorded in 2002.