Sean Carroll can keep driving his anti-fossil-fuel message through Rhode Island and beyond, after all. Carroll, of Scituate, ran afoul of the state Division of Motor Vehicles last year because of his vanity license plate, which reads “FKGAS.” The DMV initially saw no problem with the plate and gave it to Carroll, but when the agency realized the plate could suggest a four-letter word popular in rush-hour traffic, the DMV ordered Carroll to turn in his plate or have his registration canceled. But Carroll fought for his message. And he won. Carroll's victory was sealed Friday when U.S. District Court Judge Mary McElroy signed a consent judgment declaring a state law unconstitutional. That law gave the DMV's administrator authority to deny vanity license plates if they “might carry connotations offensive to good taste and decency," according to the Rhode Island ACLU, which took up Carroll's cause.