In Milwaukee, gas prices shot above $4 a gallon at many stations, up from $3.75 Thursday.
Tony SanFelippo, who manages a downtown Milwaukee Citgo station, said drivers like to blame gas station owners when prices rise but they're at the mercy of suppliers. He said that, like a lot of people, he's changed his driving habits.
"My wife says to me, 'We sit on the patio a lot lately.'" Then he smiled and offered this advice: "Learn to walk again. Exercise the legs."
Associated Press writers John Flesher in Traverse City, Mich., David Mercer in Savoy, Ill., and Roger Schneider in Milwaukee contributed to this report.
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