Motoring organisations VAB and Touring expect very heavy holiday traffic on European roads on Saturday, with the busiest conditions in France, Germany, Italy, Austria and Switzerland.
Touring has issued a red traffic alert for people setting off on holiday to those countries. Both organisations expect conditions to ease on Sunday.
France remains the most popular holiday destination and transit country, adding to congestion on motorways heading south. VAB expects major delays on Saturday towards the Mediterranean, the Atlantic coast, Normandy and the Alps.
VAB has also warned travellers about wildfires in France. Because of a fire in Fontainebleau, south-east of Paris, the A6 motorway between Paris and Dijon was closed in both directions in recent days.
The motorway has been partially reopened since Thursday evening, but restrictions remain in place. VAB is also warning of severe thunderstorms, mainly in the Alps and the Pyrenees.
Heavy traffic is also expected in Germany. The main trouble spots are the A3, A5, A7, A8 and A9, where roadworks could cause extra delays.
In southern Germany, including Bavaria and the Black Forest, thunderstorms are possible, especially towards the Alps.
In Austria, VAB expects heavy traffic on all north-south routes, particularly on Saturday. Key pressure points include the Brenner motorway towards Italy, the Fern Pass route and the Tauern motorway towards Slovenia.
Weekend exit bans are in force in Tyrol along the Inntal motorway, or A12, to stop rat-running. There is also a high risk of thunderstorms in the Alps.
In Switzerland, traffic is expected to build around Zurich, the Gotthard Tunnel and San Bernardino. Saturday is likely to be especially busy on routes towards Italy.
The Alpine region could also see heavy rain, thunderstorms and strong gusts of wind. Because of the increased risk of severe weather, VAB is urging travellers to check their insurance cover before departure.
