The next time you hit the road on business, make sure to calculate your millage using multiple online map services. For business road trips you are reimbursed for the number of miles driven, not gas bought. Differences in online map services means a variation of an average of 2 miles.
So if you use Google Maps and compare to MapQuest, you might be able to squeeze out a few extra bucks. At 48.5 cents per mile, and a few road trips per year, it adds up.
To maximize the efficiency of your gas millage avoid traffic, find out the weather forecast along the way, or take public transportation.