"US citizens drove 9.6 billion fewer miles in May 2008 than in May 2007, or 3.7% less. Yet May usually means an increase in traffic because of Memorial Day vacations and the beginning of summer."
I don't think Memorial Day being in May means May this year has an increase in traffic over May last year, that would've only made sense if they compared April and May
...which says that not only are we seeing a drop compared to last year, but we are also seeing month-by-month drops, which is unusual because May has historically been an "up" month.
Yeah, I coughed when I read this too. The reason a May-over-May comparison is made is to take out the seasonality; Memorial Day is irrelevant to May08/May07 (or, as they would say in finance, 07K-08K).
I don't think Memorial Day being in May means May this year has an increase in traffic over May last year, that would've only made sense if they compared April and May