Hi all,
I have some question for you. For my personal interesting, I analyzed
10 years traffic volume data (Twin Cities) on major highways. In
terms of monthly traffic volume, it shows that the traffic volume has
been increased since January to June. AND, suddenly it dropped down
on July and it suddenly
increased on August.
The pattern also appears in another metro areas.
I wish some one knows the reason that traffic is decreased on July in
urban areas. Do you have any idea?

The reasons that I can think as follows.
1. school's out
2. July 4th vacation
3. summer vacation

If you have different idea, please share with me.
Thanks.