[wagonman76]

Guess I don't get how it would work in the real world. They are assuming that everybody is going to the same place.

I can get better mpg when taking the old Mackinaw trail instead of the freeway when going downstate. I believe it is mainly due to the wind from the clear-cut freeway, plus driving the minimum speed is not the greatest feeling when everyone else is going considerably over the speed limit.

Plus its not just better mpg. Several times coming home, I filled up at the same station downstate first then came straight home. But when taking old side road, I found that it is 150 miles, and taking the freeway is 155 miles. More fuel saved.