InsideClimate: California is replacing oil with cleaner-burning fuels in cars and trucks, thanks to a landmark low-carbon fuel rule, according to a recent report. But the rule's fate is uncertain amid legal chaos and a shortfall in the production of clean biofuels. The report, conducted by researchers at the Institute of Transportation Studies at the University of California, Davis, said California drivers saved more than two billion gallons of gasoline in the two years since the launch of the ruleabout as much...