I really think you are overestimating college students' impact on fuel consumption. If you think January fuel consumption goes down partly due to colleges being on break, you have to factor that decrease in the summer months as well, making the summer month jumps even higher than they appear. There are other statistics that when considered along with fuel consumption would paint a better picture of the summer driving season. For example, you may have to look at non-weather related accidents, citations, etc... I'm also sure that someone in the DOT does traffic counts on highways that shows that there is an increase in traffic in the summer months. Looking at fuel consumption alone isn't going to tell you the whole story because you have to consider gas prices, fuel efficiency, and such as well. Edit: Here is a link to 2014 traffic counts in Wisconsin Counties A-Kewaunee. For each site, I looked at the MADT (Monthly Average Daily Traffic) column, and at nearly every site where data was collected, traffic in the summer months was higher, in some instances significantly higher, than in the winter months. http://wisconsindot.gov/Documents/projects/data-plan/traf-counts/cont2014-a-k.pdf Here's a link to all of the data the WIDOT collects...http://wisconsindot.gov/Pages/projects/data-plan/traf-counts/default.aspx