I have heard that close to 40% of loss of MPG can be attributed to the resistance loss of pushing our FEH brick through the dead air. I have found from experiments close to this while driving against a wind, drafting behind trucks to vans, and having a tailwind. It is true. So if you can still be safe, why not?

Mike Maline - Sdctcher
2005 Ford Escape Hybrid Owner
California School Teacher