Drafting for economy

[yaris-me]

I've read about drafting behind big rigs and using the truck to reduce air drag. I bought a PLX Kiwi a few weeks ago and lately been using the MPG bar gauge. I return home late at night and the freeway is empty and at 80mph the current MPG gauge shows ~54MPG. Tonight I was behind a 70's Cadillac and decided to move up and draft. At about 40 to 60 feet behind at 80mph it was showing 60 to 70MPG. It's a short distance to get home about 6 or 7 miles and the trip gauge usually shows 34MPG. Tonight it was 36MPG. Not scientific, but certainly something to think about.