U.S. gasoline prices could fall below $4/gal as soon as Tuesday, CBS reports. AAA said the national average for regular gasoline was $4.0093/gal on Monday, down more than $0.36 MoM and $0.16 WoW. Diesel has fallen only about $0.10 MoM and remains roughly $2.44/gal above year-ago levels, though below its Sept. 22 record high. Seasonal switch to lower-cost winter-blend fuel, weaker driving demand and the winding down of refinery maintenance are set to raise refinery output and add supply.