We all knew it was coming. All the major metropolitan school systems are back in session, and the usual traffic mayhem has ensued.

But the reality of traffic conditions on the streets may be better than the public's perception of them, at least according to statistics provided by the Georgia Department of Transportation.

The Atlanta Journal-Constitution wanted to get a true picture of how traffic changes after classes start back. So we requested data from 16 traffic counter sites on the interstates and 9 traffic counter sites on arterial roads all around metro Atlanta. The numbers reflected morning rush period conditions during one week in July and one week in August of 2014, so before and after children returned to school.

SECONDARY PHOTO: April 22, 2013 - Stockbridge, Ga: Rush hour traffic travel southbound on I-75 south past a sign reading, "Heavy traffic possible during spring break," as they approach the Jodeco Road exit Monday afternoon in Stockbridge, Ga., April 22, 2013. Georgia is about to construct its first new toll road since Ga. 400 and almost no one is talking about it. In Henry County and a small part of Clayton, I-75 will soon sprout additional lanes, to be tolled electronically, and the project goes out to bid in two months. JASON GETZ / JGETZ@AJC.COM

Credit: Andria Brooks

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Credit: Andria Brooks

The data shows that traffic was about the same at the interstate sites, however there was a great deal of variance from location to location. For example, traffic volume increased by 14 percent at I-75 Southbound at West Paces Ferry Road. But it decreased by 17 percent at I-85 Southbound at Beaver Ruin Road.

Traffic on the selected arterial roads was consistently worse on the whole, with an average volume increase of 12.6 percent.

Interestingly, the total amount of vehicles counted on the selected days only increased by 2.8 percent from July to August. That means that the numbers of people on the road stayed roughly the same from month to month. It's just that when school started back, drivers tended to shift their travel times so that more of them are traveling between 6 a.m. and 9 a.m.

To see the detailed results, visit this link: http://www.myajc.com/news/back-to-school-2015/?icmp=AJC_081015_AJCtoMyAJC_schooltraffic