Key to victory? A car key, perhaps. Michael Arno, whose company is spearheading the drive to qualify Molly Munger's tax measure for the November ballot, plans to give away a car each week in a drawing involving his top signature gatherers. The weekly winner can choose a favorite vehicle in the $15,000 price range, said Arno, whose firm must gather 504,760 valid voter signatures. County elections officials must confirm voter signatures by June 28, so the secretary of state has suggested that campaigns submit their petitions to local government by April 20. Clearly, it's pedal-to-the-metal time for initiative drives.