TAMPA — As 5.5 million Americans hit the road this week, gas prices will be the highest for the Thanksgiving holiday in three years though they are starting to dip. The average for regular gasoline in Florida is $2.50, 40 cents more than a year ago, AAA reports. But prices have dropped an average of 3 cents in the last four days and are expected to decline by up to 10 cents through the Thanksgiving weekend."Although gasoline demand will be high this week, it will be cheaper for gas stations to purchase their fuel than a week ago," said Mark Jenkins, an AAA spokesman. "Since retailers profit more off of concessions in their convenience stores than the sale of gasoline, they will be more likely to lower gas prices as a way to attract passing motorists."Florida’s all-time high price for regular gas was $4.07 in July 2008.