Today is expected to be the busiest travel day of the festive season, with predictions of 18 million cars on the roads.The Highways Agency is suspending roadworks on a number of motorway and major A-road sites in England over the holiday period, although problems still remain on some key routes, including the M1 and M25, for safety reasons.A record 3.5 million Britons are thought to be heading abroad for Christmas. Spain's Canary Islands are high on the list of destinations of those travelling overseas during the festive period, travel association ABTA said.Egypt, Goa and Dubai are also proving popular, while many skiers are heading for the slopes in France, Austria and Italy.Top city-break destinations include Paris, Amsterdam, Dublin and New York.ABTA said the busiest day for overseas travel will be Saturday, followed by December 30 when people head off for New Year's Eve celebrations abroad.Between December 21 and January 2, a total of 1.2 million passengers are expected to leave from Heathrow airport in west London.ABTA president Justin Fleming said: "This is always a peak time for travel as people make the most of the bank holidays and once again there are a record number travelling."Suggestions that milder weather is on the way has prompted bookmakers to lengthen the odds on a White Christmas.Paul Mott, of MeteoGroup, said: "Anyone who's put money on a White Christmas is unlikely to win anything. We're not expecting snow on the day and it's actually likely to be a lot milder than of late."© Independent Television News Limited 2007. All rights reserved.