The state?s gas allocation system is explained by James Ikehoff of the Civil Defense Office. Mandatory gas allocations affect how much gas suppliers have to sell. Gas stations could run short. The federal energy office has predicted a national gasoline shortage of 20 percent by summer. Right now the office handles more than 200 calls each day. Dixie Diehl says most callers are concerned with inadequate gas supplies. To compensate filling stations pump only two or three gallons of gas per customer to stay open.