I make a habit out of reading the owner's manual of every car I test-drive. It's mostly to learn about the car, and partly to assemble my annual "Auto Funnies" column -- 2007 is here, and 2008 is over here.
These manuals are intended to inform people who don't know anything about their cars. So I could only shake my head when I read this in the Toyota Prius' manual:
Your vehicle must use only unleaded gasoline.Select octane rating 88 (Research Octane Number 92). Use of unleaded gasoline with an octane rating lower than 88 may result in engine knocking. At minimum, the gasoline you use should meet the specifications of ASTM D4814 in the U.S.A. and CGSB3.5-M93 in Canada.
Why, yes, thank you, that's much clearer!